RU2535844C2 - Explosive composition for processing metals by explosion - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: explosive composition for processing metals by explosion contains a ballistite mass of colloxylin, nitroglycerin and dimethyldiphenylurea in a specified ratio as a structural-mechanical base, diethanolnitraminedinitrate or dinitrotoluene, or their composition as an additional plasticiser and energy additive and azo-bis-isobutyronitrile as a gas-generating agent.

EFFECT: creation of the explosive composition, possessing the small critical detonation thickness, the wide range of detonation rates, physical stability, which does not have critical density and suitable for processing components of a complex configuration.

1 tbl, 5 ex

Description

The invention relates to industrial explosives (BB), intended for the processing of metals by explosion, mainly for welding, as well as for blasting operations in the extraction of stone blocks.

Known explosive ammonite A-2 [1], which is a mechanical mixture of granular and crystalline ammonium nitrate (AS) (93 wt.%) With a solution of TNT (TNT) (1.4 wt.%) In dibutyl phthalate (5.6 wt. %).

The disadvantages of the known explosives are:

- a relatively narrow range of values of the velocity of detonation D = 2.5-4.5 km / s with a slightly increased velocity value at the lower level, while it is known [2] that for explosion welding the values of the velocity of detonation of explosives should be in the range of 1.5 -5.0 km / s and not exceed the speed of sound in the welded metals;

- large critical detonation thickness h _cr = 35-55 mm;

- the presence of a critical density ρ _cr , above which ammonite A-2 loses its ability to detonate;

- inherent disadvantages for most powdered ammonium nitrate explosives:

a) the complex technology of preparing flat charges, consisting in the need to make a wooden or cardboard mold, to fill in the explosive form and leveling to form a charge with constant height, density and distribution of components to ensure detonation stability, this is difficult to achieve in the manufacture of powder charges for processing parts of complex shape;

b) low physical stability, determined by factors:

moistening, when wetted to ~ 1.5 wt.% or more, the detonation speed decreases and the detonation ability of explosives deteriorates [3];

caking, leading to loss of flowability of explosives [4] and the impossibility of forming charges with constant required characteristics;

delamination of explosives into components, this occurs at a moisture content of less than 0.8 wt.% and leads to unpredictable local fluctuations in the detonation velocity and, as a result, deterioration in the quality of welded joints [3].

Known explosive ammonite AT [5], selected as a prototype, containing TNT 3-8 wt.% And ammonium nitrate 93-97 wt.%.

The disadvantages of ammonite AT are:

- a relatively narrow range of detonation velocity values of 1.5-3.8 km / s;

- large critical detonation thickness h _cr = 10-40 mm;

- the presence of a critical density ρ _cr = 1.4-1.5 g / cm ³ above which ammonite AT loses its ability to detonate;

- other disadvantages inherent in most powdered ammonium nitrate explosives noted above for ammonite A-2.

The technical result of this invention is the creation of an explosive composition for the processing of metals by explosion, mainly for welding, as well as for blasting operations in the extraction of stone blocks that do not have critical density, having a wide range of detonation speeds, a small critical detonation thickness and physical stability, suitable for processing parts flat and complex configuration.

The result is achieved in that the explosive composition for processing metals by explosion includes, as a structurally-mechanical base, a ballistic mass of colloxylin, nitroglycerin and dimethyl diphenylurea (centralite No. 2) in a ratio of 58: 40: 2 wt.%, Respectively, as an additional plasticizer and energy additive contains diethanolitramine dinitrate (DINA) or dinitrotoluene, or their composition and as a chemical blowing agent azo-bis-isobutyronitrile (porphore ChZh-57) with the following components, wt.%:

- ballistic mass of colloxylin, nitroglycerin and dimethyldiphenylurea 70.93-86.87; - diethanolitramine dinitrate or dinitrotoluene, or their composition 12.96-28.54; azo bis isobutyronitrile 0.1-0.7

The introduction into the explosive composition of ballistic mass from colloxylin, nitroglycerin and centralite No. 2 in a ratio of 58: 40: 2 wt.% In the amount of 70.93-86.87 wt.%, Respectively, forms the energy and structural-mechanical basis of the composition, causing high explosive characteristics and physicochemical stability of charges. Physico-mechanical and thermophysical characteristics of the mass allow it to be processed (rolled and molded) using ballistic technology. The highest Newtonian viscosity of ballistic mass is 98 × 10 ⁵ Pa · s.

The introduction as an additional plasticizer DINA or dinitrotoluene, or their composition in an amount of 12.96-28.54 wt.% Reduces the Newtonian viscosity of the composition to 11.5 × 10 ⁵ -0.05 × 10 ⁵ Pa · s, due to which foaming the properties of the ChHZ-57 porophore, introduced into the composition in an amount of 0.1-0.7 mass%, are realized more fully, which makes it possible to control the density, detonation velocity, and critical thickness of the composition over a wide range.

The characteristics of the samples of the explosive composition and prototype are shown in the table.

For a better understanding of the invention, an example is given of a technology for producing 1000 g of sample No. 3 of an explosive composition (see table) containing a ballistic mass of colloxylin, nitroglycerin and centralite No. 2 in a ratio of 58: 40: 2 wt.%, Respectively, in an amount of 863.4 g , DINA in the amount of 129.6 g and porphore ChKhZ-57 in the amount of 7 g.

The sample was manufactured using standard ballistic technology. Water was poured into a mixer with a paddle mixer and heated to a temperature of 55-60 ° C. Then the ballistic components were loaded.

Table - Recipes and characteristics of explosive composition for metal processing by explosion and prototype Indicators Prototype [5] Explosive samples for the processing of metals by explosion one 2 3 four 5 Composition, wt.%: - trotyl; 3-7 - - - - - - ammonium nitrate; 93-97 - - - - - - ballistic mass of colloxylin, nitroglycerin and centralite No. 2 in a ratio of 58: 40: 2, respectively; - 90.27-90.82 86.34-86.87 79.44-79.93 73.55-74.0 70.93-71.36 - DINA or dinitrotoluene or their composition; - 9.03-9.08 12.96-13.03 19.86-19.97 25.75-25.9 28.37-28.54 - porphore CHX3-57. - 0.7-0.1 0.7-0.1 0.7-0.1 0.7-0.1 0.7-0.1 Explosive and physico-mechanical characteristics: Critical detonation thickness h _cr , mm 10-40 10-4,2 9.7-6.0 9.1-9.5 8.5-13.0 8.2-14.6 Knock speed D, km / s 1,5-3,8 3.0-7.80 2.76-7.72 2.36-5.14 1.96-2.43 1.75-1.05 The critical density ρ _cr , g / cm ³ 1.4-1.5 - - - - - The charge density ρ _s , g / cm ³ 0.85-0.90 1.45-1.60 1.36-1.56 1.20-1.47 1.03-1.38 0.94-1.33 The highest Newtonian viscosity η, Pa · s - 26 × 10 ⁵ 11.5 × 10 ⁵ 2.4 × 10 ⁵ 0.1 × 10 ⁵ 0.05 × 10 ⁵

mass in the following sequence: colloxylin in the amount of 466.24 g, nitroglycerin in the amount of 384.21 g in 6-7 doses in small portions and centralit No. 2 in the amount of 12.95 g. Stirring was carried out for 20 minutes. Then, in 5-6 doses, a portion of 129.6 g of additional DINA plasticizer was dosed into the mixer and the whole mass was mixed for the next 10 minutes. Lastly, finely dispersed porphore CHX3-57 was introduced in an amount of 7 g in the composition of an aqueous-acetone suspension. The ratio of mass to water was 1: 8. After 10 minutes of stirring, the contents of the mixer were cooled to room temperature, water was squeezed from the mass on a Buchner funnel. In order to remove residual moisture, averaging the composition and plasticization, the mass was processed on smooth rollers at a temperature of 60-65 ° C.

From the rolled mass by hydropress technology, a tape was obtained by forcing the mass through slotted sleeves with different slit heights at a temperature of 60-70 ° C. The tape was cut into pieces of various widths and lengths. Then the pieces of the sample were placed in molds and then in a heating cabinet. During thermostating at 95 ° C, the samples foamed. After cooling, the porous plates were trimmed with a sharp knife if necessary.

Similarly manufactured samples No. 1-2 and 4-5 explosive composition.

When the content of ballist mass from colloxylin, nitroglycerin and centralite No. 2 in a ratio of 58: 40: 2, respectively, in the amount of 90.27-90.82 wt.%, Additional plasticizer diethanolitramine dinitrate or dinitrotoluene, or their composition in the amount of 9.03-9, 08 wt.%, As well as a gasifier of azo-bis-isobutyronitrile in an amount of 0.1-0.7 wt.% (Sample No. 1), the physicomechanical and explosive characteristics of the composition have the following meanings: the highest Newtonian viscosity η = 26 × 10 ⁵ Pa · s, density ρ _s = 1.45-1.6 g / cm ³ , critical detonation thickness h _kp = 4.2-10 mm, detonation velocity D = 3.0-7.8 km / s.

Compared to the prototype, sample No. 1 has a smaller critical thickness and a wider range of detonation velocity values, however, the lower interval value for sample No. 1 was significantly higher (3.0 km / s) than for the prototype (1.5 km / s), although it is known [2] that for explosion welding the values of the detonation velocity of explosives should be in the range of 1.5-5.0 km / s. The presence of an upper level of the detonation velocity of about 7.8 km / s in the sample allows us to expand the field of application and use it also in explosion hardening of metals, which require explosives detonating at a speed of 7-8 km / s [5]. A significant drawback of sample No. 1 is insufficient elasticity, which does not allow it to fit snugly against the workpiece without gaps.

When the content of DINA or dinitrotoluene or their composition in the amount of more than 29 wt.%, Porphore CHKhZ-57 in the amount of 0.1-0.7 wt.% And ballistic mass of colloxylin, nitroglycerin and centralite No. 2 in the ratio, respectively, 58: 40: 2 the rest is the highest Newtonian viscosity decreases to (0.01-0.02) × 10 ⁵ Pa · s and the composition is difficult to process. During rolling and formation, the mass adheres to the surfaces of technological equipment, the shape of the foamed samples and their porosity after minor mechanical influences are not completely restored, which negatively affects the stability of the physicomechanical and explosive characteristics of the composition.

The best characteristics are for samples No. 2-5 of the composition, including ballist mass from colloxylin, nitroglycerin and centralite No. 2 in a ratio of 58: 40: 2, respectively, in the amount of 70.93-86.87 wt.%, DINA or dinitrotoluene plasticizer, or composition in an amount of 12.96-28.54 wt.%, as well as a blowing agent porphore CHKhZ-57 in an amount of 0.1-0.7 wt.%.

Compared with the prototype, samples No. 2-5 have higher density values (ρ _s = 0.94-1.56 g / cm ³ ), lower critical thickness values (h _cr = 6.0-14.6 mm), a wider range of detonation velocity values (D = 1.05-7.72 km / s), do not have a critical density (detonate in the entire range of charge densities), are physically stable. The values of the highest Newtonian viscosity η = (0.05-11.5) × 10 ⁵ Pa · s determine their rather high elasticity and tight fit to the surfaces of the workpieces with a flat and complex configuration.

In determining the characteristics of samples of explosive composition for processing metals by explosion, the following methods were used:

the critical detonation thickness (h _cr ) was determined by a series of detonations of flat charges of various thicknesses, the charge width was not less than 5 thicknesses, the length not less than 10 charge thicknesses, the critical detonation thickness was determined as the arithmetic mean between the thickness at which detonation decay was observed , and the nearest thickness at which steady detonation was observed along the entire length of the charge;

- the detonation velocity was determined by OST B 84-900-74;

- charge density (ρ _s ) was determined according to GOST 14839.18-69;

- viscosity was determined by the viscometric method with the material of the composition being forced through smooth capillaries of the same diameter and different lengths, the highest Newtonian viscosity was determined at a strain rate close to 0 s ^-1 using the graphical dependence of viscosity η on the strain rate Y constructed in logarithmic coordinates. Test conditions: weight of the test sample 30 g; test temperature 90 ° C; strain rate 0-10 s ^-1 .

In the manufacture of explosives for the processing of metals by explosion, the following are used:

- Colloxylin grade N according to GOST B 84-2440-90 or varnished according to GOST 5936-73, or TU 7508403-138-93;

- nitroglycerin according to GOST B 84-2386-88;

- centralite No. 2 (dimethyldiphenylurea) according to GOST 2154-77;

- dinitrotoluene according to OMTU 280-55, OST B 84-1461-77 or TU 7511903-600-92;

- DINA (diethanolitramine dinitrate) according to TU 84520-318-81;

- porphore CHX3-57 (azo-bis-isobutyronitrile) according to TU 113-03-365-82;

- acetone GOST 2768-84.

The advantages of the claimed explosive composition compared with the prototype are lower values of the critical detonation thickness (h _cr 6.0-14.6 mm), a wider range of detonation velocity values (D = 1.05-7.72 km / s), the absence critical density ρ _cr , higher values and a wide range of charge densities (ρ _z = 0.94-1.56 g / cm ³ ), higher physical stability, suitability for machining parts of a flat and complex configuration, wider scope: welding , mining of stone blocks and hardening of metals by explosion.

INFORMATION SOURCES

1. Industrial explosives. Ammonite A-2. Specifications TU 84-1005-84.

2. Welding of metals in metallurgy. Kudinov V.M., Koroteev A.Ya. M., Metallurgy, 1978. 168 p. (Series "New Pressure Welding Processes").

3. Zakharenko I.D. Explosion welding of metals. - Мn .: Science and technology, 1990. - 205 p.

4. Dubnov L.V. Bakharevich N.S., Romanov A.I. Industrial explosives. - 3rd ed., Revised. and add. - M .: Nedra, 1988 .-- 358 s: ill.

5. Ammonites AT. Specifications TU 7511903-624-93.

6. A.A. Deribas. Physics of hardening and explosion welding. - Novosibirsk: Nauka, 1980, 221 p.

Claims (1)

An explosive composition for metal processing by explosion, mainly for welding, characterized in that it contains a ballistic mass of colloxylin, nitroglycerin and dimethyl diphenylurea in a ratio of 58: 40: 2 wt.%, Respectively, it contains diethanololitramine dinitrate or dinitrotoluene as an additional plasticizer and energy additive, or their composition and as a blowing agent contains azo-bis-isobutyronitrile in the following components, wt.%:
ballox mass from colloxylin, nitroglycerin and dimethyldiphenylurea 70.93-86.87 diethanolitramine dinitrate or dinitro toluene, or their composition 12.96-28.54 azo bis isobutyronitrile 0.1-0.7