Outline "brief information about explosives, their classification, safety rules when handling them." · use of equipment designed for explosion pressure

Topic No. 1: Explosives and charges. Lesson #1: General information about explosives and charges. Study questions. 1. General information about explosives. Explosive charges. 2. Storage, accounting and transportation of explosives and explosives. 3. Requirements for working with explosives and explosives. Responsibility of military personnel for the theft of explosives and military equipment.

1. General information about explosives. Explosive charges. Explosives are called chemical compounds or mixtures that, under the influence of certain external influences, are capable of self-propagating chemical transformation with the formation of highly heated and high-pressure gases, which, when expanding, produce mechanical work.

An explosion is characterized by the following factors: the speed of the process of chemical transformation of substances, which is the most important characteristic of an explosion and is measured by a time interval from 0.01 to 0.000001 fractions of a second; the release of a large amount of heat, which allows the transformation process that has begun to develop rapidly; the formation of a large amount of gaseous products, which, due to high temperature, expand greatly, create high pressure and produce mechanical work, expressed in throwing, splitting or crushing surrounding objects. In the absence of at least one of these factors, there will be not an explosion, but combustion.

An explosion is an extremely rapid chemical (explosive) transformation of a substance, accompanied by the release of heat (energy) and the formation of compressed gases capable of producing mechanical work. The external influence necessary to initiate an explosion, an explosive, is called the initial impulse. The process of igniting an explosive explosion using an initial impulse is called initiation. The initial impulse for the initiation of explosives are various forms of energy, namely: - mechanical (impact, puncture, friction); - thermal (spark, flame, heating); - electrical (spark discharge); - explosion energy of another explosive (explosion of a detonator capsule or detonation at a distance); - chemical (reaction with large heat release).

Tasks performed with the help of explosives are called blasting. Blasting operations are used: 1. When constructing engineering barriers in order to delay the enemy’s advance. 2. For the rapid destruction of objects with military significance, in order to prevent the enemy from using these objects to his advantage. 3. When creating passages in engineering obstacles, rubble, etc. 4. When destroying unexploded ammunition. 5. When developing soils and rocks in order to speed up and facilitate defensive and construction work. 6. For the construction of lanes when equipping crossings in winter conditions. 7. When carrying out work to protect bridges and hydraulic structures during ice drift. 8. When performing other engineering support tasks. In addition, explosives are used for loading engineering ammunition, making standard demolition charges, artillery ammunition, aerial bombs, sea mines and torpedoes.

According to practical application, all explosives are divided into three main groups: I. Initiating. II. Blasting. III. Throwing. The group of high explosives, in turn, is divided into three subgroups: 1. High-power explosives. 2. Explosives of normal power. 3. Reduced power explosives

I. Initiating explosives (mercury fulminate, lead azide, TNPC) are highly sensitive to impact, friction, and fire. The detonation of these explosives is used to detonate a charge consisting of explosives less sensitive to shock, friction and flame. Initiating explosives are used to equip detonator caps, igniter caps, and electric detonators. II. High explosives differ from initiating explosives by being significantly less sensitive to various external influences. Detonation is usually initiated in them using initiation means (detonator capsule). Their relatively low sensitivity to impact and, therefore, sufficient safety in handling ensure the success of their practical application.

High explosives are divided into: - High power explosives. These include: PETN, hexogen, tetryl. They are used for the manufacture of intermediate detonators, detonating cords and for equipping certain types of ammunition. Explosives of normal power. These include: TNT (Tol), picric acid, plastic 4. They are used for all types of blasting (for blasting metal, stone, brick, concrete, reinforced concrete, wood, soil and structures made from them), for equipping mines and constructing landmines . TNT (tol, trinitrotoluene, TNT) is the main high explosive of normal power. It is a crystalline substance from light yellow to light brown, bitter in taste, practically insoluble in water, highly soluble in gasoline, acetone, ether, and boiling alcohol. Burns in the open air without explosion. Combustion in a confined space can lead to detonation. TNT is little sensitive to external influences and does not interact with metals. TNT is commercially produced in 4 types: powdered, pressed (explodes from the detonator capsule KD No. 8), fused, flake (explodes from an intermediate detonator made of pressed TNT).

The intermediate detonator is used to load engineering and other types of ammunition and serves to reliably transfer detonation from the detonator capsule to the main explosive charge. For the manufacture of intermediate detonators, tetryl, PETN, and pressed TNT are used. For blasting operations, TNT is usually used in the form of pressed blasting blocks: large - measuring 50 X 100 mm and weighing 400 g; small - dimensions 25 X 50 X 100 mm and weight 200 g; - drilling (cylindrical) - 70 mm long, 30 mm in diameter and weighing 75 g.

Reduced power explosives. These include: ammonium nitrate explosives, ammonium nitrate. They are used mainly for charges placed inside a destructible environment, as well as for constructing landmines, loading mines and exploding metal, stone, and wood. Compared to explosives of normal power, charges from high-power explosives are taken at half the weight, and charges from low-power explosives are one and a half to two times heavier.

Propellant explosives (gunpowder). They are used as charges in cartridges for various types firearms and for the manufacture of fire cord (OSH) – black powder. The main form of their explosive transformation is rapid combustion caused by the action of fire or spark on them. Representatives of this explosive are black and smokeless powder. Black powder - black - 75% potassium nitrate, 15% coal, 10% sulfur. Smokeless powder– gray yellow color until brown. Nitrocellulose with the addition of an alcohol-ether mixture or nitroglycerin + stabilizers for storage stability.

Industrially manufactured charges Elongated - can be manufactured by the military or come from industry in finished form, and have the shape of elongated parallelipipeds or cylinders, the length of which is more than 5 times greater than their smallest transverse dimensions. The height of the ultrasound should not be greater than its width; the best case is that the height and width are equal. Ultrasounds are used to make explosive passages in PT, PP, minefields enemy. Ultrasounds of industrial production are produced in the form of metal, plastic pipes filled with pressed TNT or in fabric casings

Figured charges. They are used to demolish various shaped structural elements, have a variety of shapes and are composed so that a larger amount of explosives falls against the thick parts of the element being undermined. TNT blocks or plastid-4 are used in these charges.

Shaped charges. They are used to pierce large thicknesses, armored, concrete, reinforced concrete defensive structures, interrupt (cut) thick metal sheets, etc. When shaped charges explode, a sharply directed narrow jet of blast wave is formed with a high concentration of energy, providing a piercing or cutting effect for a significant depth. Factory-produced shaped charges are produced various shapes in metal cases and with metal lining cumulative cavities, which further enhances the piercing (cutting) effect of the jet

SZ-1 It is a sealed metal box filled with an explosive. On one end side it has a carrying handle, on the opposite side there is a threaded socket for an EDPr electric detonator. Conventional incendiary tubes, standard incendiary tubes ZTP-50, ZTP-150, ZTP-300, detonating cord with detonator cap KD No. 8 a, electric detonators EDP and EDPr, fuses MD-2 and MD-5 with special fuses. The charge is painted dark green. Has no markings Specifications charge SZ-1: Mass. . . 1. 4 kg. Mass of explosive (TG-50). . . 1 kg. Dimensions. . . . 65 x116 x126 mm. In a box weighing 30 kg. 16 charges are packed.

SZ-3: It is a sealed metal box filled with an explosive. On one end it has a carrying handle, on the opposite and on one of the sides there is a threaded socket for an EDPr electric detonator. Conventional incendiary tubes, standard incendiary tubes ZTP-50, ZTP-150, ZTP-300, detonating cord with detonator cap KD No. 8 a, electric detonators EDP and EDPr, fuses MD-2 and MD-5 with special fuses. The charge is painted dark green. Has no markings. Technical characteristics of the SZ-3 charge: Weight. . . . 3. 7 kg. Mass of explosive (TG-50). . . . . 3 kg. Dimensions. . . . . 65 x171 x337 mm. In a box weighing 33 kg. 6 charges are packed.

SZ-6: It is a sealed metal box filled with an explosive. It has a carrying handle on one side. In addition, on the body there are four metal rings and two rubber bands with carbines 100 (150) cm long. , which allows you to quickly attach a charge to the object being undermined. On one of the end sides there is a threaded socket for an EDPr electric detonator. On the opposite end side it has a socket for a special fuse for the purpose of using the charge as a special mine. Conventional incendiary tubes, standard incendiary tubes ZTP-50, ZTP-150, ZTP-300, a detonating cord with a detonator cap KD No. 8 a, electric detonators EDP and EDPr, fuses MD-2 and MD-5 with special fuses can be used as means of explosion. , special fuses. The charge is painted in spherical (wild grey) color. The markings are standard. The charge can be used underwater at depths of up to 100 m. Technical characteristics of the SZ-3 a charge: In a box weighing 48 kg. 5 charges are packed. Weight. . . 7. 3 kg. Mass of explosive (TG-50). . . 5. 9 kg. Dimensions. . . . 98 x142 x395 mm.

KZU This charge is designed for punching oblong holes in steel (metal) plates, armored closures, reinforced concrete and concrete slabs, walls, breaking complex metal beams of T-, I-beam, and truss sections. The KZU charge consists of a metal case with a threaded socket for standard detonator caps KD No. 8, electric detonators EDP, EDP-r, a metal carrying handle, and four brackets for fastening elements. Technical characteristics of the charger: Weight. . . 18 kg. Mass of explosive (TG-50). . . . . 12 kg. Max. body diameter. . . 11. 2 cm. Installation depth in water. . . . up to 10 m. The charge penetrates: - armor. . . . . up to 12 cm - reinforced concrete. . . up to 100 cm - soil. . . . . up to 160 cm.

KZ-6 Designed for breaking through protective layers of armor and holes in soils and rocks, breaking through steel and reinforced concrete beams, columns, sheets, as well as for destroying ammunition, weapons and equipment. diameter – 112 mm; - height – 292 mm; - explosive mass – 1.8 kg; - charge weight – 3 kg; - mass of charge with weighting agent – ​​4.8 kg. Penetration capacity: - armor – 215 mm (diameter 20 mm), - reinforced concrete – 550 mm, - soil (brick) – 800 mm (diameter 80 mm). The number of charges in the box is 8;

KZK This charge is designed to break steel (metal) pipes, rods, and cables. The KZK charge consists of two half-charges connected to each other on one side by a hinged, easily disconnected connection, and on the other side by a spring latch. Metal plates are inserted between the charge halves. On both halves of the charge there are sockets for standard detonator caps KD No. 8, electric detonators EDP, EDP-r. In the middle part of each half-charge there is a spring in the tube. (FOR CENTERING) The cumulative recess is filled with a foam liner (shown in greenish-blue in the picture). Technical characteristics of the KZK charge: Weight. . . . . 1 kg. Mass of explosive (TG-50). . . . 0.4 kg. Charge thickness…. . . . 5. 2 cm charge length. . . 20 cm. Charge width. . . . . 16 cm. Installation depth in water up to 10 m. The charge is interrupted by: - ​​steel rod with diameter. . . up to 70 mm. - steel cable diameter. . . up to 65 mm. The half-charge is interrupted by: - ​​a steel rod in diameter. . up to 30 mm. - steel cable diameter. . . up to 30 mm.

2. Storage, accounting and transportation of explosives and explosives. The procedure and rules for drawing up documents for receiving, spending and writing off explosives, explosives and demolition charges. Explosive materials and explosives are received from the warehouse by the head of blasting operations with the permission of the unit commander. The following documentation is submitted to the unit headquarters: Calculation-application for receiving explosives and SV (see Appendix No. 1) List of personnel familiarized with precautionary measures and passed the tests (with signatures and received grades). Then a part-by-part order is issued to carry out blasting operations. Based on an extract from the order, as well as a calculation-application signed by the unit commander and stamped, an invoice for the issuance of explosives and SV is issued, signed by the head of the service and the deputy commander for armaments. According to the invoice, the warehouse manager issues explosives and CBs in the prescribed manner. The work manager signs for receipt of explosives and explosives. At the blasting site, explosives and explosives are issued from the field consumable warehouse, as a rule, according to the written Requirements of the work manager (see Appendix No. 2). The warehouse manager keeps records of issued explosives and explosives according to the statement and saves all the work manager’s requirements for their issuance. After the completion of the blasting work, an Act is drawn up for the write-off of spent explosives and explosives (see Appendix No. 3), which is signed by the chairman of the commission (the head of the blasting work) and the members of the commission (from the demolition team). After this, the Act is approved by the unit commander and handed over to the deputy commander for weapons (in the technical unit).

Rules for transporting and carrying explosives and explosives. Loading standards for vehicles. After receiving explosives and SV from the warehouse of a military unit, their delivery to the field consumable warehouse is carried out by car in compliance with following rules: Explosives and explosives must be tightly packed and secured in the car body. The installation height must be such that top row boxes rose above the side by no more than 1/3 of the height of the box. There should be no foreign or flammable objects in the body; transportation must be provided with armed guards; significant quantities of explosives and explosives are transported separately. Small quantities, with the permission of the unit commander, can be transported on one vehicle (explosive - no more than 200 kg; CD, EDP - no more than 400 pieces). The distance between the explosive and the CB must be at least 1.5 m; the car must have a fire extinguisher (or a box of sand), a tarpaulin to cover the cargo, a red flag on the left front corner of the body; driving speed should not exceed 25 km/h; smoking in the car is prohibited; big cities on the path of movement must be bypassed. If a detour is not possible, travel on the outskirts of cities is allowed; during a thunderstorm, it is forbidden to stop a car with explosives and explosives in the forest, under individual trees and near tall buildings; stops along the route are allowed only outside populated areas and no closer than 200 m from residential buildings.

The issuance of explosives and explosives at the field consumable warehouse is carried out by the warehouse manager, as a rule, according to the written Requirements of the work manager. Accounting is carried out according to the Sheet of Issue of Explosives and SVs (see Appendix No. 4). Explosive and explosive charges are transported to the places of installation (laying) in factory capping or in serviceable bags that prevent explosives and explosives from falling out. In this case, explosives and explosives must be transported separately. When carrying explosives and explosives together, a demolitionist can carry no more than 12 kg of explosives. When carried in bags or sacks without CB, the norm can be increased to 20 kg. CDs are carried in wooden cases, EDPs are carried in cardboard boxes. It is prohibited to carry explosive and explosive charges in pockets. One person is allowed to carry one LSh bay and up to five OSh bays along with explosives. If the quantity is larger, these cords are carried separately from the explosives. Persons carrying explosives and explosives to work sites must move in a column one at a time at a distance of at least 5 m.

3. Safety requirements when working with explosives and explosives. Responsibility of military personnel for the theft of explosives and military equipment. During blasting operations, the following requirements apply: during blasting operations, strict order and precise implementation of instructions and instructions from senior superiors is necessary; a commander or senior person responsible for the success of the explosion and the correct conduct of the work is assigned to each blasting operation; all persons assigned to carry out work must know explosives, explosives, their properties and rules for handling them, the order and sequence of work; the beginning and termination of work, all actions during the work are carried out according to the commands and signals of the commander: commands and signals must be sharply different from one another and all personnel involved in blasting operations must know them well; the explosion site should be cordoned off with posts that should be removed to a safe distance. The cordon is set up and removed by the guard, subordinate to the work manager (senior); signals are given by radio, voice, rockets, sirens in the following order: a) the first signal is “Get ready”; b) the second signal – “Fire”; c) the third signal – “Move away”; d) fourth signal – “All clear”. persons not directly involved in these works, as well as unauthorized persons, are not allowed into the work site;

- Explosive explosive charges are located in the field consumable warehouse and are guarded by a sentry. Detonator capsules, incendiary tubes, electric detonators are stored separately from explosives and are issued only by order of the work manager (senior); CD and ED are inserted into external charges after strengthening the charges on the elements (objects) to be exploded and after the withdrawal of personnel, immediately before the explosion, when exploding certain structural elements with external charges, they should retreat to a safe distance. When carrying out an explosion in tunnels (shafts, pits, etc.), you can enter them only after thorough ventilation or forced ventilation; no more than one person should approach failed (not exploded) charges, but not earlier than after 15 minutes; When leaving the blasting site, all unspent explosives and explosives must be handed over to the field consumable warehouse, and those unsuitable for further use must be destroyed at the work site.

Responsibility of military personnel for the theft of explosives and military equipment. Article 226 of the Criminal Code of the Russian Federation provides for liability for the theft or extortion of firearms, their components, ammunition, explosives or explosive devices, nuclear, chemical, biological or other types of weapons of mass destruction, as well as materials and equipment that can be used in the creation weapons of mass destruction, including by a person using his official position, with the use of violence, etc. The theft of weapons and other objects of crime should be understood as the unlawful taking of them by any means with the intention of the perpetrator to appropriate the stolen property or transfer it to another person, as well as to dispose of it in his own way discretion in another way (for example, destroy). Criminal liability for the theft of weapons and ammunition occurs in the event of their theft both from public, private or other enterprises or organizations, and from individual citizens who owned them lawfully or illegally. A person who has committed theft or extortion of weapons, ammunition and other items using his official position should be understood as both a person to whom weapons and other items were personally issued for a certain period of time for official use, and a person to whom these items were entrusted for protection (for example , theft of weapons from a warehouse or from another place by a person performing security guard functions; official and financial responsible person, in whose possession weapons and other items were due to his official position).

Theft of firearms, ammunition and explosives. Theft of firearms (except for smooth-bore hunting weapons), ammunition and explosives is punishable by imprisonment for up to 7 years. The same act, committed repeatedly or by prior conspiracy by a group of persons, or committed by a person to whom firearms, ammunition or explosives were issued for official use or entrusted under guard, is punishable by imprisonment for a term of up to 10 years. Theft of firearms, ammunition or explosives, committed by robbery or by a dangerous repeat offender, is punishable by imprisonment for a term of 6 to 15 years.

"APPROVED" Commander of military unit 18590, Lieutenant Colonel __________Ivanov "____" ________ 200__ CALCULATION - APPLICATION for receiving explosives and SV from the warehouse for conducting training with personnel in explosives. No. Number of trainees Naimenov Unit. change CV and SV TOTAL: _____________ LESSON LEADER Major ______ Petrov "________200__. Required quantity Total for one student. Note.

REQUIREMENT No. ______ for the issuance of explosives and blasting means Issue _______________________ the following quantity of explosives and explosives: No. Name p Unit. change Quantity 1 TNT in checkers of 200 g. 2 Detonator caps KD No. 8-A 3 Fire cord kg pcs. 1 5 m 5 TOTAL: _____________ WORK MANAGER Major ______ Petrov "________200__ Note

"APPROVED" Commander of military unit 18590, Lieutenant Colonel __________Ivanov "____" ________ 200__ ACT "___" _______ 20__ Kamensk-Shakhtinsky The commission consisting of: _______________________ drew up this act in that "___" ________ 20__. according to invoice No. _______ dated "___" ________ 20__. The following quantities of explosives and explosives were received from the unit's warehouse and completely consumed during blasting operations during training with personnel: 1. TNT in checkers 200–400 g. ___________ 2. Detonator capsules No. 8-A ___________ 3. ZTP- 50 ___________ 4. ZTP- 150 ___________ 5. OSHP fire cord ___________ 6. DSh detonating cord ___________ There were no failures during the explosions. After the end of classes, the blasting site was inspected. No remaining or unexploded explosives or explosives were found. The act was drawn up for the purpose of writing off the above-mentioned explosives and explosives from the accounting unit. BLASTING MANAGER _______________________ Members of the commission: 1. ________________ 2. ________________ 3. ________________

RECEIPT for issuing explosives and explosives "____" ________ 200__g. 1 Explosive means Issued in accordance with Requirement No. 1 Remaining 3 Issued in accordance with Request No. 2 Remaining 4 Issued in accordance with Requirement No. 3 Remaining 5 Issued in accordance with Request No. 4 Remaining 6 Issued in accordance with Requirement No. 5 Remaining 7 Destroyed "________200__ WORK MANAGER ______________ Head of the explosives warehouse SV ____________ DSh, pcs. OSH, pcs. NWT, pcs. Signed in receipt Received 2 TNT EDP, pcs. Basis for issuance and balance of explosives and SV CD No. 8 D, pcs. Explosive No. p/p

General information about explosives and

thermochemistry of explosive processes

IN economic activity People, we often encounter explosive phenomena (explosions).

In the broadest sense of the word, “explosion” is the process of a very rapid physical and chemical transformation of a system, accompanied by the transition of its potential energy into mechanical work.

Examples of an explosion include:

• 
  explosion of a vessel operating under high pressure (steam boiler, chemical vessel, fuel tank);
• 
  explosion of a conductor when it short-circuits a powerful source of electricity;
• 
  collision of bodies moving at high speeds;
• 
  spark discharge (lightning during a thunderstorm);
• 
  eruption;
• 
  nuclear explosion;
• 
  explosion of various substances (gases, liquids, solids).

We will study explosions of special substances that are widely used in national economic activity. More precisely, in the process of studying we will consider the “explosion” as the main property of the substances we are studying - industrial explosives.

In relation to explosives (in particular to explosive explosives), an explosion should be understood as a process of extremely rapid (instantaneous) chemical transformation of a substance, as a result of which its chemical energy is converted into the energy of highly compressed and heated gases that perform work during their expansion.

The above definition gives three characteristic features of an “explosion”:

• 
  high rate of chemical transformation;
• 
  the formation of gaseous products of chemical decomposition of a substance - highly compressed and heated gases that play the role of a “working fluid”;
• 
  exothermic reaction.

Let's look at the factors that determine an explosion in more detail.

Exothermicity reaction is the most important condition explosion. This is explained by the fact that the explosive explosive explosion is excited by an external source that has a small amount of energy. This energy is only sufficient to cause an explosive transformation reaction of a small mass of explosive located at a point on the line or plane of initiation. Subsequently, the explosion process spreads spontaneously throughout the explosive mass from layer to layer (layer-by-layer) and is supported by the energy released in the previous layer. The amount of heat released ultimately determines not only the possibility of self-propagation of the explosion process, but also its beneficial effect, that is, the performance of the explosion products, since the initial energy of the working fluid (gases) is completely determined by the thermal effect of the chemical reaction of the “explosion”.

High speed of reaction propagation explosive transformation is his characteristic feature. The explosion process of some explosives occurs so quickly that it seems that the decomposition reaction occurs instantly. However, it is not. The speed of propagation of an explosive explosion, although large, has a finite value (the maximum speed of propagation of an explosive explosion does not exceed 9000 m/s).

The presence of highly compressed and heated gaseous products is also one of the main conditions for an explosion. Expanding sharply, compressed gases produce a shock to the environment, exciting it shock wave, which performs the planned work. Thus, the jump (difference) in pressure at the interface between the explosive and the environment, which occurs at the initial moment, is a very characteristic sign of an explosion. If no gaseous products are formed during a chemical transformation reaction (i.e. there is no working fluid), the reaction process is not explosive, although the reaction products may have a high temperature without having other properties, they cannot create a pressure jump and, therefore, cannot make work.

The necessity of the presence of all three factors considered in the explosion phenomenon will be illustrated with some examples.

Example 1 Coal burning:

C + O 2 = CO 2 + 420 (kJ).

During combustion, heat is released (there is exothermicity) and gases are formed (there is a working fluid). However, the combustion reaction is slow. Therefore, the process is not explosive (there is no higher rate of chemical transformation).

Example 2 Thermite burning:

2 Al + Fe 2 O 3 = Al 2 O 3 + 2 Fe +830 (kJ).

The reaction proceeds very intensively and is accompanied big amount released heat (energy). However, the resulting reaction products (slags) are not gaseous products, although they have a high temperature (about 3000 o C). The reaction is not an explosion (there is no working fluid).

Example 3 Explosive transformation of TNT:

C 6 H 2 (NO 2) 3 CH 3 = 2 CO + 1.2 CO 2 + 3.8 C + 0.6 H 2 + 1.6 H 2 O +

1.4N 2 +0.2 NH 3 +905 (kJ).

Example 4 Explosive decomposition of nitroglycerin:

C 3 H 5 (NO 3) 3 = 3CO 2 +5 H 2 O + 1.5N 2 + Q (kJ).

These reactions proceed very quickly, heat is released (the reactions are exothermic), and the gaseous products of the explosion, expanding, do work. The reactions are explosive.

It must be borne in mind that the above main factors determining the explosion should not be considered in isolation, but in close relationship both with each other and with the conditions of the process. Under some conditions, the chemical decomposition reaction can proceed calmly, while in others it can be explosive. An example is the combustion reaction of methane:

CH 4 + 2O 2 = CO 2 + 2H 2 O + 892 (kJ).

If methane combustion occurs in small portions and its interaction with atmospheric oxygen occurs along a fixed contact surface, the reaction has the character of stable combustion (there is exothermicity, there is gas formation, there is no high speed of the process - no explosion). If methane is pre-mixed with oxygen in a significant volume and combustion is initiated, the reaction rate will increase significantly and the process can become explosive.

It should be noted that the high speed and exothermic nature of the process gives the impression that explosives have an extremely large energy reserve. However, it is not. As follows from the data given in Table 2.1, in terms of heat content (the amount of heat released during the explosion of 1 kg of a substance), some flammable substances are much superior to explosives.

Table 2.1 - Heat content of some substances

The difference between the explosion process and conventional chemical reactions is the greater volumetric concentration of the released energy. For some explosives, the explosion process occurs so quickly that all the released energy at the first moment is concentrated almost in the initial volume occupied by the explosive. It is impossible to achieve such a concentration of energy in reactions of a different kind, for example, from the combustion of gasoline in car engines.

Large volumetric concentrations of energy created during an explosion lead to the formation of specific energy flows (specific energy flow is the amount of energy transmitted through a unit area per unit time, dimension in W / m 2) of high intensity, which predetermines the greater destructive ability of the explosion.

2.1. Classification of explosive processes

The following factors have a decisive influence on the nature of the explosion process and its final result:

• 
  the nature of the explosive, i.e. its physicochemical properties;
• 
  conditions for excitation of a chemical reaction;
• 
  conditions under which the reaction occurs.

What is common in both examples considered is that the chemical decomposition by mass (volume) of TNT occurs sequentially from one layer to another. However, the speed of propagation of the reacting layer and the mechanism of decomposition of TNT particles in the reacting layer will be completely different in each case. The nature of the processes occurring in the reacting explosive layer ultimately determines the rate of propagation of the reaction. However, the opposite statement is also true: the speed of propagation of a chemical reaction can also be used to judge its mechanism. This circumstance made it possible to place the reaction rate of explosive transformation as the basis for the classification of explosive processes. Based on the speed of reaction propagation and its dependence on conditions, explosive processes are divided into the following main types: combustion, explosion (actual explosion) and detonation .

Combustion processes proceed relatively slowly (from 10 -3 to 10 m/s), while the combustion rate significantly depends on external pressure. The greater the pressure in the environment, the greater the burning rate. In the open air, combustion proceeds calmly. In a limited volume, the combustion process accelerates and becomes more energetic, which leads to a rapid increase in the pressure of gaseous products. In this case, the gaseous combustion products acquire the ability to produce throwing work. Combustion is a characteristic type of explosive transformation of gunpowder and rocket fuels.

The actual explosion Compared to combustion, it is a qualitatively different form of process propagation. Distinctive features explosion are: a sharp jump in pressure at the site of the explosion, a variable speed of propagation of the process, measured in thousands of meters per second and relatively little dependent on external conditions. The nature of the explosion is a sharp impact of gases on the environment, causing crushing and severe deformation of objects located near the explosion site. The process of explosion differs significantly from combustion in the nature of its propagation. If during combustion the energy is transferred from the reacting layer to the adjacent unexcited explosive layer by thermal conductivity, diffusion and radiation, then during an explosion the energy is transferred by compressing the substance by a shock wave.

Detonation represents a stationary form of the explosion process. The speed of detonation during an explosion occurring under given conditions does not change and is the most important constant of a given explosive. Under detonation conditions, the maximum “destructive” effect of the explosion is achieved. The mechanism for excitation of the explosive transformation reaction during detonation is the same as during the explosion itself, that is, the transfer of energy from layer to layer occurs in the form of a shock wave.

The explosion occupies an intermediate position between combustion and detonation. Although the mechanism of energy transfer during an explosion is the same as during detonation, the processes of energy transfer in the form of thermal conductivity, radiation, diffusion, and convention cannot be neglected. That is why an explosion is sometimes considered as non-stationary, combining the combination of the effects of combustion, detonation, expansion of gaseous products and other physical processes. For the same explosive, under the same conditions, the explosive transformation reaction can be classified as intense combustion (gunpowder in a gun barrel). Under other conditions, the process of explosive transformation of the same explosive occurs in the form of an explosion or even detonation (for example, an explosion of the same gunpowder in a hole). And although during an explosion or detonation processes characteristic of combustion are present, their influence on the general mechanism of explosive decomposition is insignificant.

2.2. Classification of explosives

Currently there are a huge number of known chemical substances, capable of explosive decomposition reactions, their number is constantly increasing. In their composition, physical and chemical properties, in their ability to excite explosion reactions in them and in their distribution, these substances differ significantly from each other. For the convenience of studying explosives, they are combined into certain groups according to various signs. We will focus on three main classification features:

• 
  by composition;
• 
  by appointment;
• 
  by susceptibility to explosive transformation (explosiveness).

Explosive chemical compounds are unstable chemical systems that, under the influence of external influences, are capable of rapid exothermic transformations, resulting in complete rupture of intramolecular bonds and subsequent recombination of free atoms, ions, groups of atoms into thermodynamically stable products (gases). Most explosives in this group are oxygen-containing organic compounds, and their chemical reaction decomposition is a reaction of complete and partial intramolecular oxidation. Examples of such PVVs include TNT and nitroglycerin (as components of PVV). However, there are other explosive compounds (lead azide , Рb(N 3 ) 2 ), not containing oxygen, capable of exothermic reactions of chemical decomposition during an explosion.

Explosive mixtures are systems consisting of at least two chemically unrelated components. Typically, one of the components of the mixture is a substance relatively rich in oxygen (oxidizer), and the second component is a flammable substance that does not contain oxygen at all, or contains it in quantities insufficient for complete intramolecular oxidation. The first ones include black powder, emulsion explosives, the second ones include ammotol, granulites, etc.

It should be noted that there is a so-called intermediate group of explosive mixtures:

• 
  substances of the same nature (explosive chemical compounds) with different contents of active oxygen (TNT, hexogen).
• 
  an explosive chemical compound in an inert filler (dynamite).

By purpose Explosives are divided into four main groups:

• 
  initiating explosives;
• 
  high explosives (including the class of industrial explosives);
• 
  propellant explosives (powder and fuel);
• 
  pyrotechnic compositions (including PVV, black powder and other igniters).

High explosives have a large reserve of energy and are less sensitive to the effects of initial impulses.

The main type of chemical decomposition of explosives and BrVVs is detonation.

A characteristic sign (type) of chemical decomposition of propellant explosives is combustion. For pyrotechnic compositions, the main type of explosive transformation reaction is also combustion, although some of them are capable of an explosion reaction. Most pyrotechnic compositions are mixtures (mechanical) of combustibles and oxidizers with various cementing and special additives that create a certain effect.

By susceptibility Explosives for explosive transformation are divided into:

• 
  primary;
• 
  secondary;
• 
  tertiary

The tertiary category includes explosives with weakly expressed explosive properties. Typical representatives of tertiary explosives can be considered ammonium nitrate and an emulsion of an oxidizer in fuel (emulsion explosives). Tertiary explosives are practically safe to handle; it is very difficult to initiate a decomposition reaction in them. Often these substances are classified as non-explosive. However, complete disregard for their explosive properties can lead to tragic consequences. When tertiary explosives are mixed with flammable materials or when sensitizers are added, their explosiveness increases.

2.3. General information about detonation, features

detonation of industrial explosives

According to the hydrodynamic theory, detonation is considered to be the movement of a chemical transformation zone along an explosive, driven by a shock wave of constant amplitude. The amplitude and speed of movement of the shock wave are constant, since the dissipative losses accompanying the shock compression of the substance are compensated by the thermal reaction of the transformation of the explosive. This is one of the main differences between a detonation wave and a shock wave, the propagation of which in chemically inactive materials is accompanied by a decrease in the speed and parameters of the wave (attenuation).

Detonation of various solid explosives occurs at speeds from 1500 to 8500 m/s.

The main characteristic of explosive detonation is the detonation speed, i.e. the speed of propagation of the detonation wave along the explosive. Due to the very fast speed of propagation of the detonation wave along the explosive charge, changes in its parameters [pressure ( R), temperature ( T), volume ( V)] in the front, the waves occur abruptly, as in a shock wave.

Scheme for changing parameters ( P,T,V) during detonation of a solid explosive is shown in Figure 2.1.

Figure 2.1 - Scheme of changes in parameters during detonation of solid explosives

Pressure ( R) increases abruptly at the front of the shock wave, and then begins to gradually fall in the chemical reaction zone. Temperature T also increases abruptly. but to a lesser extent than R, and then, as the chemical transformation proceeds, the explosive increases slightly. Volume V occupied by the explosive, due to the high pressure, decreases and remains practically unchanged until the end of the transformation of the explosive into detonation products.

Hydrodynamic theory of detonation (Russian scientist V.A. Mikhalson (1890), English scientist physicist D. Chapman, French scientist physicist E. Jouguet), based on the shock wave theory (Yu.B. Khariton, Ya.B. Zeldovich, L.D. Landau), makes it possible, using data on the heat of transformation of explosives and on the properties of detonation products (average molecular weight, heat capacity, etc.), to establish a mathematical relationship between the speed of detonation, the speed of movement of explosion products, the volume and temperature of detonation products.

To establish these dependencies, generally accepted equations are used that express the laws of conservation of matter, momentum and energy during the transition from the initial explosive to its detonation products, as well as the so-called Jouguet equation and the equation of state of detonation products, expressing the relationship between the main characteristics of the explosion products. According to Jouguet's equation, during a steady process, the detonation speed D equal to the sum of the speed of movement of detonation products behind the front  and speed of sound With in detonation products:

D =  +s. (2.1)

For detonation products of “gases” that have a relatively low pressure, the well-known equation of state of ideal gases is used:

PV=RT (2.2)

Where P- pressure,

V – specific volume,

R– gas constant,

T- temperature.

For detonation products of condensed explosives L.D. Landau and K.P. Stanyukovich derived the equation of state:

PV n =const , (2.3)

Where P And V- pressure and volume of explosion products at the moment of their formation;

n= 3 - exponent in the equation of state for condensed explosives (polytropic index) at explosive density >1.

Detonation speed according to hydrodynamic theory

, (2.4)

Where - heat of explosive transformation.

However, the values ​​obtained from this expression
are always overestimated, even taking into account the variable, depending on the explosive density, value " n" Nevertheless, for a number of estimates it is useful to use such a dependence in general form:

D = ƒ (p O )
, (2.5)

Where p O– explosive density.

For approximate estimates of the detonation rate of a new substance (if it is not possible to determine it experimentally), the following relation can be used:

, (2.6)

Where is the index " X" refers to an unknown (new substance), and " THIS" - to the reference one with a known detonation velocity at equal densities and assumed close values ​​of the polytrope ( n).

Thus, the detonation speed depends on three main characteristics of an explosive: the heat of its explosion, the density and composition of the explosion products (via “ n" And " M * »).

The transformation of explosives in the form of detonation is the most desirable, since it provides a significant rate of chemical transformation and creates the highest pressure and density of explosion products. This provision can be observed under the condition formulated by Yu.B. Khariton:

   , (2.7)

Where  - duration of chemical transformation of explosives;

 - dispersion time of the initial explosive.

Yu.B. Khariton introduced the concept of critical diameter, the value of which is one of the most important characteristics of an explosive. The relationship between the reaction time and the dispersion time allows us to give a correct explanation of the presence of a critical or limiting diameter for each explosive.

If we take the speed of sound in the explosion products through “ With", and the charge diameter through "d", then the time of dispersal of the substance can be approximately determined from the expression

. (2.8)

Considering that the condition for the possibility of detonation  >, can be written down >, where does the critical diameter come from, i.e. the smallest diameter at which stable detonation of an explosive can still occur will be equal to:

d cr =с. (2.9)

From this expression it follows that any factor that increases the time of dispersal of a substance should contribute to detonation (shell, increase in diameter). There will also be factors that accelerate the process of chemical transformation of explosives in a detonation wave (the introduction of highly active explosives - powerful and susceptible).

Experimental measurements show the asymptotic nature of the increase in detonation velocity with increasing charge diameter. Starting from the maximum charge diameter d etc, with further increase, the speed practically does not increase (Figure 2.2).

Figure 2.2 - Detonation speed dependence D on charge diameter d h :

D AND-ideal detonation speed; d cr– critical diameter; d etc– maximum diameter.

The critical geometric characteristics of the charge also depend on the density of the explosive and its homogeneity. For individual explosives, the density decreases with increasing density. d cr, up to the region close to the density of a single crystal, where, as A.Ya. Apin showed, a slight increase can be observed d cr(for example for TNT).

If the diameter of the explosive charge is significantly higher than the critical one, then an increase in the explosive density leads to an increase in the detonation speed, reaching a limit at the maximum possible explosive density.

For ammonium nitrate explosives, the critical diameters are relatively large. In commonly used charges, the effect of density is dual: an increase in density initially leads to an increase in detonation speed ( D), and then with a further increase in density, the detonation speed begins to fall and detonation may decay. For each ammonium nitrate explosive, depending on the conditions of its use, there is its own “critical” density. Critical is the maximum density at which (under given conditions) stable detonation of an explosive is still possible. With a slight increase in the “charge” density above the critical value, detonation fades.

Critical density ( p cr) (maximum points on the curve D= ( O ) ) is not a constant of a particular industrial explosive, determined by its chemical composition. It changes with changes in the physical characteristics of the explosive (particle sizes, uniform distribution of component particles in the mass of the substance), the transverse dimensions of the charges, the presence and properties of the charge shell.

Based on these ideas, secondary explosives are divided into two large groups. For type 1 explosives, which include mainly powerful monomolecular explosives (TNT, hexogen, etc.), the critical diameter of stationary detonation decreases with increasing explosive density. For type 2 explosives, on the contrary, the critical diameter increases with decreasing porosity (increasing density) of the explosive. Representatives of this group are, for example, ammonium nitrate, ammonium perchlorate, and a number of mixed industrial explosives: ANFO (ammonium nitrate + diesel fuel); emulsion explosives, etc.

For type 1 explosives, the detonation speed D cylindrical charge with diameter d increases monotonically with increasing density  O explosive. For type 2 explosives, the detonation speed first increases as the porosity of the explosive decreases, reaches a maximum, and then decreases until detonation stops at the so-called critical density. Non-monotonic dependency behavior D= ( O ) for mixed (industrial) explosives is associated with difficult filtration of explosive gases, absorption of detonation wave energy by inert additives, multi-stage explosive transformation of individual components, incomplete mixing of the explosion products of components and a number of other factors.

It is believed that as the porosity of an explosive decreases, the detonation velocity first increases due to an increase in the specific explosion energy Q V, because D~
, and then decreases for the reasons stated above.

2.4. Main characteristics of explosives.

Explosive sensitivity

Since the appearance of explosives, their high danger under mechanical and thermal influences (shock, friction, vibration, heating) has been established. The ability of explosives to explode under mechanical influences was defined as sensitivity to mechanical influences, and the ability of explosives to explode under thermal influences was defined as sensitivity to thermal influences (thermal impulse). The intensity of the impact, or, as they say, the magnitude of the minimum initial impulse required to initiate an explosive decomposition reaction, can be different for different explosives and depends on their sensitivity to a particular type of impulse.

To assess the safety of production, transportation and storage of industrial explosives, their sensitivity to external influences is of great importance.

There are various physical models of the occurrence and development of an explosion under local external influences (impact, friction). In the study of explosive sensitivity, two concepts have become widespread about the causes of an explosion under mechanical influences - thermal and non-thermal. Everything about the causes of an explosion due to thermal influence (heating) is clear and unambiguous.

According to non-thermal theory– the excitation of an explosion is caused by the deformation of molecules and the destruction of intramolecular bonds due to the application of certain critical pressures of uniform compression or shear stresses to the substance. In accordance with thermal theory When an explosion occurs, the energy of the mechanical action dissipates (dissipates) in the form of heat, leading to heating and ignition of the explosive. In creating ideas about the thermal nature of the sensitivity of explosives, the ideas and methods of the theory of thermal explosion, developed by academicians N.N. Semenov, Yu.B. Khariton and Ya.B. Zeldovich, D.A. Frank-Kamenetsky, A.G. Merzhanov.

Since the rate of thermal decomposition of explosives, which determines the possibility of a reaction occurring via the thermal explosion mechanism, is an exponential function of temperature (Arrhenius law: k=k O e - E/RT), then it becomes clear why not the total amount of dissipated heat, but its distribution over the volume of the explosive should play a decisive role in the processes of initiation of an explosion. In this regard, it seems natural that the various paths through which mechanical energy is converted into heat are unequal to each other. These ideas came Starting point to create a local thermal (focal) theory of explosion initiation. (N.A. Kholevo, K.K. Andreev, F.A. Baum, etc.).

According to the focal theory of explosion excitation, the energy of mechanical action does not dissipate uniformly throughout the entire volume of the explosive, but is localized in individual areas, which, as a rule, are physical and mechanical inhomogeneities of the explosive. The temperature of such areas (“hot spots”) is much higher than the temperature of the surrounding homogeneous body (substance).

What are the reasons for the appearance of a hot spot during mechanical action on an explosive? It can be considered that internal friction is the main source of heating of viscoplastic bodies that have a homogeneous physical structure. High-temperature hot spots in liquid explosives under shock-mechanical influences are mainly associated with adiabatic compression and heating of gas or explosive vapors in small bubbles scattered throughout the volume of the liquid explosive.

What is the size of the hot spots? The maximum size of hot spots that can lead to an explosive explosion under mechanical stress is 10 -3 - 10 -5 cm, the required temperature increase in the hot spots reaches 400-600 K, and the heating duration ranges from 10 -4 to 10 -6 s.

L.G. Bolkhovitinov concluded that there is a minimum bubble size that is capable of collapsing adiabatically (without heat exchange with the environment). For typical conditions of mechanical shock, its value is about 10 -2 cm. Film footage of the collapse of the air cavity is presented in Figure 2.3

Figure 2.3 - Stages of bubble collapse during compression

What determines the sensitivity of explosives and what factors influence its value?

Such factors include the physical state, temperature and density of the substance, as well as the presence of impurities in the explosive. As the temperature of an explosive increases, its sensitivity to impact (friction) increases. However, such an obvious postulate is not always clear in practice. As proof of this, an example is always given when charges of ammonium nitrate with the addition of fuel oil (3%) and sand (5%), in the middle of which steel plates were placed, exploded when shot by a bullet at normal temperature, but did not explode under the same conditions with preliminary heating the charge to 60 0 S. S. M. Muratov pointed out that in in this example the factor of change in the physical state of the charge with a change in temperature and, what is especially important, the conditions of inter-boundary friction between the moving object and the explosive charge are not taken into account. The effect of temperature is often offset by other temperature-related factors.

Increasing the density of an explosive usually reduces sensitivity to impact (friction).

The sensitivity of explosives can be specifically adjusted by introducing additives. To reduce the sensitivity of explosives, phlegmatizers are introduced, and to increase them, sensitizers are introduced.

In practice, you can often encounter such sensitizing additives - sand, small rock particles, metal shavings, glass particles.

TNT giving in pure form when tested for impact sensitivity 4-12% explosions, when 0.25% sand is introduced into it gives 29% explosions, and when 5% sand is introduced it gives 100% explosions. The sensitizing effect of impurities is explained by the fact that the inclusion of solid substances in explosives contributes to the concentration of energy on solid particles and their sharp edges upon impact and facilitates the conditions for the creation of local “hot spots”.

Substances with a hardness less than the hardness of explosive particles soften the impact, create the possibility of free movement of explosive particles and thereby reduce the likelihood of energy concentration in individual “points”. Low-melting substances, oily liquids with good enveloping ability and high heat capacities are usually used as phlegmatizers: paraffin, ceresin, petroleum jelly, various oils. Water is also a phlegmatizer for explosives.

2.5. Practical assessment of explosive sensitivity

For practical assessment (determination) of sensitivity parameters, there are various methods.

2.5.1. Sensitivity of explosives to thermal

impact (impulse)

The minimum temperature at which, over a conventionally specified period of time, the heat input becomes greater than the heat removal and the chemical reaction, due to self-acceleration, takes on the character of an explosive transformation, is called the flash point.

The flash point depends on the explosive test conditions - sample size, device design and heating rate, therefore the test conditions must be strictly regulated.

The period of time from the start of heating at a given temperature until the outbreak occurs is called the flash delay period.

The flash delay is shorter, the higher the temperature to which the substance is exposed.

To determine the flash point, which characterizes the sensitivity of an explosive to heat, use a device “to determine the flash point” (a sample of the explosive is 0.05 g, the minimum temperature at which a flash occurs 5 minutes after placing the explosive in a heated bath).

The flash point is for

The sensitivity of explosives to heating is more fully characterized by a curve showing the dependence

T av = ƒ(τ ass).

and in

Figure 2.4 - Dependence of flash delay time (τ set) on heating temperature ( O WITH) - schedule " A", and also the dependence in logarithmic form (Arrhenius coordinates) lgτ ass - ƒ(1/T, K)- schedule " V».

2.5.2. Sensitivity to fire

(flammability)

Industrial explosives are tested for susceptibility to the fire ray of a fire cord. To do this, 1 g of PVV is placed in a test tube mounted on a stand. The end of the OSHA is inserted into the test tube so that it is at a distance of 1 cm from the explosive. When the cord burns, the flame beam, acting on the explosive, can cause it to ignite. In blasting operations, only those explosives are used that do not give a single flash or explosion in 6 parallel definitions. Explosives that do not withstand such a test, such as gunpowder, are used in blasting operations only in exceptional cases.

In another version of the test, the maximum distance at which the explosive still ignites is determined.

Since gunpowder was invented, the world race for the most powerful explosive has not stopped. This is still relevant today, despite the advent of nuclear weapons.

RDX is an explosive drug

Back in 1899, for the treatment of inflammation in the urinary tract, the German chemist Hans Genning patented the drug hexogen, an analogue of the well-known hexogen. But doctors soon lost interest in him due to side intoxication. Only thirty years later it became clear that hexogen turned out to be a powerful explosive, and more destructive than TNT. A kilogram of hexogen explosive will produce the same destruction as 1.25 kilograms of TNT.

Pyrotechnicians mainly characterize explosives as high explosive and brisant. In the first case, they talk about the volume of gas released during the explosion. Like, the larger it is, the more powerful the high explosive. Brisance, in turn, depends on the rate of gas formation and shows how explosives can crush surrounding materials.

During an explosion, 10 grams of hexogen release 480 cubic centimeters of gas, while TNT releases 285 cubic centimeters. In other words, hexagen is 1.7 times more powerful than TNT in terms of high explosiveness and 1.26 times more dynamic in terms of explosiveness.

However, the media most often uses a certain average indicator. For example, the “Baby” atomic charge, dropped on the Japanese city of Hiroshima on August 6, 1945, is estimated at 13-18 kilotons of TNT. Meanwhile, this does not characterize the power of the explosion, but indicates how much TNT is needed to release the same amount of heat as during the specified nuclear bombing.

HMX - half a billion dollars for air

In 1942, the American chemist Bachmann, while conducting experiments with hexogen, accidentally discovered a new substance, octogen, in the form of an impurity. He offered his find to the military, but they refused. Meanwhile, several years later, after it was possible to stabilize the properties of this chemical compound, the Pentagon became interested in octogen. True, it was not widely used in its pure form for military purposes, most often in a cast mixture with TNT. This explosive was called "octolome". It turned out to be 15% more powerful than hexogen. As for its effectiveness, it is believed that one kilogram of HMX will produce the same amount of destruction as four kilograms of TNT.

However, in those years, the production of HMX was 10 times more expensive than the production of RDX, which hindered its production in the Soviet Union. Our generals calculated that it was better to fire six shells with hexogen than one with octol. This is why the explosion of an ammunition depot in Vietnamese Qui Ngon in April 1969 cost the Americans so much. At the time, a Pentagon spokesman said that due to guerrilla sabotage, the damage amounted to $123 million, or approximately $0.5 billion in current prices.

In the 80s of the last century, after Soviet chemists, including E.Yu. Orlov, developed an effective and inexpensive technology for the synthesis of octogen, and it began to be produced in large quantities here.

Astrolite - good, but smells bad

In the early 60s of the last century American company EXCOA has unveiled a new hydrazine-based explosive, claiming it is 20 times more powerful than TNT. Pentagon generals who arrived for testing were knocked off their feet by the terrible smell of an abandoned public toilet. However, they were ready to tolerate it. However, a series of tests with aerial bombs filled with astrolite A 1-5 showed that the explosive was only twice as powerful as TNT.

After Pentagon officials rejected the bomb, EXCOA engineers proposed new version this explosive is already under the brand name “ASTRA-PAK”, and for digging trenches using the directed explosion method. In the commercial, a soldier sprayed the ground in a thin stream and then detonated the liquid from his hiding place. And the human-sized trench was ready. On its own initiative, EXCOA produced 1000 sets of such explosives and sent them to the Vietnamese front.

In reality, everything ended sadly and anecdotally. The resulting trenches emitted such a disgusting smell that American soldiers sought to leave them at any cost, regardless of orders and the danger to their lives. Those who remained lost consciousness. The military personnel sent the unused kits back to the EXCOA office at their own expense.

Explosives that kill your own

Along with hexogen and octogen, hard-to-pronounce tetranitropentaerythritol, which is more often called PETN, is considered a classic explosive. However, due to its high sensitivity, it was never widely used. The fact is that for military purposes, it is not so much the explosive that is more destructive than others that is important, but the one that does not explode on any touch, that is, with low sensitivity.

Americans are especially picky about this issue. It was they who developed the NATO standard STANAG 4439 for the sensitivity of explosives that can be used for military purposes. True, this happened after a series of serious incidents, including: the explosion of a warehouse at the American Bien Ho Air Force Base in Vietnam, which cost the lives of 33 technicians; disaster aboard the aircraft carrier USS Forrestal, which damaged 60 aircraft; detonation in an aircraft missile storage facility aboard the USS Oriskany (1966), also with numerous casualties.

Chinese Destroyer

In the 80s of the last century, the substance tricyclic urea was synthesized. It is believed that the first to receive this explosive were the Chinese. Tests showed huge destructive force“urea” - one kilogram of it replaced twenty-two kilograms of TNT.

Experts agree with these conclusions, since the “Chinese destroyer” has the highest density of all known explosives, and at the same time has the maximum oxygen coefficient. That is, during an explosion, all material is completely burned. By the way, for TNT it is 0.74.

In reality, tricyclic urea is not suitable for military applications, primarily due to poor hydrolytic stability. The very next day, with standard storage, it turns into mucus. However, the Chinese managed to obtain another “urea” - dinitrosourea, which, although worse in explosiveness than the “destroyer,” is also one of the most powerful explosives. Today the Americans are producing it at their three pilot plants.

A pyromaniac's dream – CL-20

The CL-20 explosive is positioned today as one of the most powerful. In particular, the media, including Russian ones, claim that one kg of CL-20 causes destruction that requires 20 kg of TNT.

It is interesting that the Pentagon allocated money for the development of the CL-20 only after the American press reported that such explosives had already been made in the USSR. In particular, one of the reports on this topic was called: “Perhaps this substance was developed by the Russians at the Zelinsky Institute.”

In reality, the Americans considered another explosive first produced in the USSR, namely diaminoazoxyfurazan, as a promising explosive. Along with high power, significantly superior to HMX, it has low sensitivity. The only thing holding him back wide application– lack of industrial technologies.

Underwater blasting.

Study questions:

1. Basic concepts about explosions and explosives.

2. Underwater explosions. Characteristics of explosives used during underwater

blasting operations.

3. Explosion methods and means of initiating industrial explosives.

Main types of underwater blasting operations and features of their implementation.

1. Underwater blasting;

Underwater excavation;

Construction of underwater engineering structures;

Repair of underwater structures;

Laying and repair of submarine cables;

Laying and repair of underwater pipelines;

Underwater cutting and welding of metals;

Literature:

1. K.A.Zabela, Yu.G.Kushniryuk. A manual on underwater technical work in construction / K. Budivelnik. – 1975 – pp. 26-25.

Basic concepts about explosions and explosives.

Explosion is the process of very quickly converting an explosive into a large number of highly compressed and heated gases, which, when expanding, produce mechanical work (destruction, movement, crushing, ejection).

Explosive- chemical compounds or mixtures of such compounds that, under the influence of certain external influences, are capable of rapid, self-developing chemical transformation into a large amount of gases.

In terms of the chemical process, an explosion represents the combustion of an explosive, but differs from simple combustion in the speed of the process, occurring in thousandths and ten-thousandths of a second. Hence, according to the speed of transformation, the explosion is divided into two types - combustion and detonation.

At burning The transfer of energy from one layer of a substance to another occurs through thermal conductivity. A combustion type explosion is characteristic of gunpowder. The process of gas formation occurs quite slowly. Due to this, when gunpowder explodes in a confined space (cartridge case, projectile), the bullet or projectile is ejected from the barrel, but the case or chamber of the weapon is not destroyed.

At detonation the process of energy transfer is determined by the passage of a shock wave through the explosive at supersonic speed (6-7 thousand meters per second). In this case, gases are formed very quickly, the pressure increases instantly to very high values. Simply put, gases do not have time to escape along the path of least resistance and, in an effort to expand, they destroy everything in their path. This type of explosion is typical for TNT, hexogen, ammonite, etc. substances.

1. Mechanical (impact, puncture, friction)
2. Thermal (spark, flame, heating)
3. Chemical (chemical reaction of interaction of any substance with explosives)
4. Detonation (explosion next to another explosive)

Depending on the type of explosion and sensitivity to external influences, all explosives are divided into three main groups:

1. Initiating explosives.
2. Throwing explosives.
3. High explosives.

Initiating explosives. They are highly sensitive to external influences and their explosion (detonation) has a detonation effect on high explosives and propellants, which are usually not sensitive to other types of external influences at all or have unsatisfactory sensitivity. Therefore, initiating substances are used only to initiate the explosion of high explosives or propellant explosives. To ensure the safety of using initiating explosives, they are packaged in protective devices (capsule, primer sleeve, detonator capsule, electric detonator, fuse). Typical representatives of initiating explosives: mercury fulminate, lead azide, teneres (TNRS).

Throwing explosives. Propellant explosives (powders) are substances whose main form of explosive transformation is combustion. When gunpowder explodes, the crushing effect is manifested to an insignificant extent compared to the action in the form of throwing away, scattering the environment, therefore, after the appearance of high explosives, they began to be called propellant explosives. Gunpowders are divided into smoky and smokeless.

High explosives. High explosives got their name from the French briser, which means to crush or break. High explosives, unlike initiating ones, do not detonate from such simple initial impulses as a spark and a beam of flame. To initiate detonation in them, an initial impulse is required in the form of an explosion of a small amount of the initiating explosive, and sometimes an explosion of the so-called intermediate detonator from another, more sensitive substance, which explodes, in turn, from the initiating explosive. High explosives are the main substances used in huge quantities for loading ammunition (artillery shells, mortar mines, aircraft bombs, sea and engineering mines) and for carrying out blasting operations for the military.

High explosives are divided into:

- Explosives of increased power, having an increased detonation speed (7500 - 8500 m/s) and releasing a large amount of heat during the explosion ( Ten, RDX, Tetryl, HMX, Nitroglycerin);

- Explosives of normal power- have great durability, can withstand long-term storage and are very little sensitive to any kind of external influences, which makes handling them practically safe ( TNT, Picric acid, Plastic explosive (plastite-4), Dynamites);

- Reduced power explosives - have reduced brisance due to significantly lower heat generation and lower detonation speed (no more than 5000 m/s), therefore they are inferior to high explosives of normal power in terms of brisant action and are equivalent to them in performance (Ammonium nitrate, Ammonites, Dynamons, Ammonals).

All explosives are characterized by a number of data, depending on the values ​​of which the issue of using this substance to solve certain problems is decided. The most significant of them are:

1. Sensitivity to external influences
2. Energy (heat) of explosive transformation
3. Detonation speed
4. Brisance
5. High explosiveness
6. Chemical resistance
7. Duration and conditions of working condition
8. Normal state of aggregation
9. Density

The properties of explosives can be described quite fully using all nine characteristics. However, to understand in general what is usually called power or strength, we can limit ourselves to two characteristics: “Blastingness” and “High Explosiveness”.

Brisance- this is the ability of an explosive to crush and destroy objects in contact with it (metal, rocks, etc.). The amount of brisance indicates how quickly gases are formed during an explosion. The higher the brisance of a particular explosive, the more suitable it is for loading shells, mines, and aerial bombs. During an explosion, such an explosive will better crush the shell of the projectile, give the fragments the greatest speed, and create a stronger shock wave. The characteristic directly related to brisance is the detonation speed, i.e. how quickly the explosion process spreads through the explosive substance.

High explosiveness- in other words, the performance of the explosive, the ability to destroy and throw out surrounding materials (soil, concrete, brick, etc.) from the explosion area. This characteristic is determined by the amount of gases formed during the explosion. The more gases are formed, the great job capable of performing this explosive.

For blasting in the ground, explosives with the greatest high explosiveness and any brisance are more suitable. For equipping shells, high explosiveness is primarily valuable and high explosiveness is not so important.

A realistic way to compare the powers of different explosives is TNT equivalent. Its essence lies in the fact that the power of TNT is conventionally taken as unity. All other explosives (including nuclear explosives) are compared with TNT. The assessment is carried out based on the condition of the required amount of TNT to perform the same blasting work as a given amount of this explosive. For example: 100g. RDX gives the same result as 125 g. TNT, and 75 gr. TNT will be replaced by 100g. ammonite.

The performance of an explosive is determined by the relative amount of substance that is released during an explosion. Determination of explosive performance will be carried out using the Trauzl method (Fig. 1).

After the explosion of the test explosive charge, the channel drilled in the cylinder turns into a cavity. This cavity is filled with water and the volume of the cavity is determined by its quantity. Explosive performance ( R) is characterized by broadening of the cavity due to the action of an explosive charge, expressed in cm 3.

P= V – (V 1 + V 2), cm 3,

Where V– volume of the cavity after the explosion, cm 3 ;

V 1 = 61.5cm 3 – initial channel volume with a channel diameter of 25 mm and a depth of 125 mm;

V 2 = 28-30cm 3 – expansion of the cavity due to the explosion of the detonator capsule.

Determination of explosive detonation speed. Can be carried out using the Dautriche method (Fig. 2).

After the explosion of the charge, the distance is measured m from the edge of the record to the point M, in which a trace remains on the plate from the meeting of detonation waves propagating along both sections of the detonating cord. The speed of explosive detonation is determined based on the equality of the time of arrival of the detonation wave at the point M through a piece of cord L 1 (t 1), and on the other hand - through an explosive charge (at a distance S) and the second piece of cord L 2 (t 2):

because the t 1 = t 2, then

from here , m/s.

The explosiveness of an explosive is determined using the Hess method (Fig. 3) and is characterized by the degree of compression of the lead column in mm.

The height of a column of refined lead is measured before and after the explosion. The change in column heights after an explosion is a relative characteristic of the brisance of an explosive.

Characteristic.

TSA are one of the main specific elements of combat strike systems. The destructive effect of SP is due to the energy released during the rapid chemical transformation of a group of substances called explosives.

The chemical transformation of explosives, occurring in an extremely short period of time, is usually called explosive, and the process itself is explosion. This phenomenon, which consists of an extremely rapid change in a substance, is accompanied by the transition of its potential energy into mechanical work.

A characteristic sign of an explosion is a sharp jump in pressure in the environment surrounding the explosion site. This pressure surge is the direct cause of the destructive effect of the explosion, which is caused by the rapid expansion of compressed gases or gases that existed either before the explosion or were formed during the explosion. The transformation explosion speed reaches 5300-7200m/sec.

Depending on the speed of propagation of the explosive reaction, three types of explosive processes are distinguished:

DETONATION - an explosion propagating with a constant maximum possible for a given explosive. and given conditions speed. The detonation speed is 5300m/sec.

COMBUSTION - the speed of the explosive process is characterized by a more or less rapid increase in pressure and the ability of gaseous combustion products to produce work. Moreover, the burning rate significantly depends on external conditions. With increasing pressure and temperature, the speed can increase significantly and after that there is an explosion. The burning speed ranges from fractions to tens of m/sec.

EXPLOSION - the speed of the explosive process is variable and is characterized by a sharp jump in pressure at the site of the explosion and the impact of gases, causing crushing and severe deformation of objects at relatively short distances.

The process of explosion differs significantly from combustion in the nature of the transfer from one to the other. During combustion, energy flows from the reacting layer to the adjacent unexcited V.V. layer. transmitted by thermal conductivity, heat radiation and convective heat exchange, and in an explosion - by compression of the substance by a shock wave.

Main properties of V.V.:

· Resistance ─ the ability to maintain physical and chemical properties under the influence of the external environment.

· Efficiency ─ mechanical work produced by highly heated gases.

· Brisance ─ the ability to crush during an explosion in contact with explosives. environment (air bomb shell, etc.).

· Sensitivity ─ the ability to undergo explosive transformation under the influence of external influences, i.e. giving an initial impulse.

The following types of energy are used as the initial impulse:

Mechanical (impact, friction);

Thermal (heating);

Electrical (spark);

Detonation (explosion of a small charge).

Requirements for V.V.:

1. Sufficient power;

2. Certain sensitivity limits;

3. Sufficient durability;

4. Economic requirements (simplicity of technology).

CLASSIFICATION OF EXPLOSIVES BY PURPOSE AND THEIR BRIEF CHARACTERISTICS .

Throwing V.V.

They are characterized by rapid combustion (up to 10 m/s). Representatives of these substances are: ─ GUNDOWPOWER - mechanical mixtures (black or smoky gun powder);

─ colloidal or smokeless powders.

Black powder: potassium nitrate 75%, charcoal 15% and sulfur 10%. Sensitive to impact, heating (tflame = 315°C) Vhot = 1-3 m/s.

Colloidal powders are based on nitroglycerin. They are less hygroscopic compared to black powder and more sensitive to mechanical and thermal impulse tflame = 170-180°C.

Application area:

· in slow pressings;

· in ignition charges;

· in expelling charges;

· for loading cartridges of small arms and cannon weapons.

Blasant V.V.

They are used as the main equipment for aerial bombs. To excite them, special means of initiation are used in the form of detonator caps. The most widely used are:

TNT is a yellow crystalline substance, slightly hygroscopic. Chemically resistant under normal storage conditions. Does not interact with metals. Little sensitive to friction and not sensitive to bullet penetration. At temperatures above 150°C it begins to decompose, is difficult to ignite and burns quietly in small quantities. Explodes at t = 300°C.

TETRYL ─ crystalline substance of light yellow color. Not exposed to light. Oxidizes most metals upon prolonged contact with them. Sensitive to shock and friction. When shot by a bullet it explodes. Highly flammable. At t above 75°C it begins to decompose, and at t above 180°C it explodes. Used as part of additional detonators and transfer charges.

HEXOGEN is a white, finely crystalline substance. Not exposed to light and moisture, does not interact with metals. Sensitive to shock and friction. Explodes when hit by a bullet. Begins to decompose at t=200°C. Highly flammable. In its pure form it is used in additional detonators and transfer charges.

Initiating V.V.

They are used to equip initiation means (caps - detonators).

Mercury fulminate is a crystalline substance of white and gray. When moistened, it loses its explosive properties and reacts with some metals (copper, aluminum). Very high sensitivity to mechanical stress, but insufficient flammability. In aircraft fuses it is used in percussion lineups capsules. It is not used in its pure form.

LEAD AZIDE is a white, finely crystalline substance. When wet, it does not lose its explosive properties and reacts with copper. It has less sensitivity to external influences than mercury fulminate and a higher (5-10 times) initiating ability.

TNRS is a finely crystalline substance of dark yellow color. Does not react with metals. Greater sensitivity to thermal impulse than other initiating V.V. Very high sensitivity to electrical discharges. Used in detonator capsules and electric igniters.

Pyrotechnic compositions.

The main type of explosive transformation is a combustion reaction that creates a pyrotechnic effect (lighting, signaling, incendiary).

Incendiary compositions - for equipping incendiary aerial bombs (IAB) and incendiary tanks (IB). GS - are created on the basis of metals (termites) or petroleum products.

THERMITE is a mechanical mixture of 75% iron oxide and 25% aluminum powder tgor = 3000°C, tflash = 1100°C. For ignition, staged ignition is used using transitional pyrotechnic igniters.

VMS-2 is an incendiary viscous liquid. Composition: organic glass, sodium nitrate, magnesium powder and other temperature = 1000°C (for ZB).

PHOTO MIXTURES - for FOTAB equipment.

Ingredients: aluminum powder, magnesium powder, spindle oil.

Related information.