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L.B. Pervukhin , T. A. Shishkin, O. L. Pervukhina

SPECIFICITY OF EXPLOSIVE WELDING IN MARGINAL ZONES. L.B. Pervukhin , T. A. Shishkin, O. L. Pervukhina. Institute of Structural Macrokinetics and Materials Science Russian Academy of Sciences Bitrub International, Ltd. EPNM -2012, Страсбург. Marginal defects occurring in welding explosion.

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L.B. Pervukhin , T. A. Shishkin, O. L. Pervukhina

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  1. SPECIFICITY OF EXPLOSIVE WELDING IN MARGINAL ZONES L.B. Pervukhin,T. A. Shishkin, O. L. Pervukhina Institute of Structural Macrokinetics and Materials Science Russian Academy of Sciences Bitrub International, Ltd. EPNM-2012, Страсбург

  2. Marginal defects occurring in welding explosion edge and corner poor penetration, "gear" trimmings overhangs the side edges of the chipped and cracked, pulling on the end of the clad layer welding stations and angles • краевые и угловые непривары,«зубчатая» обрезь нависаний по боковым кромкам со сколами и трещинами, вырывы плакирующего слоя на конечных участках сварки и углах

  3. Research technique Determine the parameters of shock-compressed gas in the welding gap in the zone established welding and marginal zones. To carry out experiments on sheets of industrial size and analyze the results of explosive welding. Develop conditions for ensuring the stability of explosive welding process over the entire surface and experimentally verify the results. • определение по известным методикам параметров в области ударно-сжатого газа (УСГ) в сварочном зазоре в зоне установившейся сварки и краевых зонах; • проведение экспериментов на листах промышленных размеров и анализ результатов сварки взрывом; • разработка условий обеспечивающих стабильность процесса сварки взрывом по всей поверхности и экспериментальная проверка результатов.

  4. The equations for determining the parameters of shock-compressed gas р1 и р0 – the absolute pressures in the shock-compressed gas area and surrounding atmosphere; V1 и V0 – gas volumes before and after compression; ρ1иρ0 – gas densities behind and before break; γ– adiabaticexponent; М – Mach number Equations of dependence determining the size of shock-compressed gas area ρ0 – flowing gas density; b – length of the line of contact, P1 – pressure in the shock-compressed gas,Vк – velocity of the point of contact,  - velocity of the gas, l - extent of the zone of shock-compressed gas, s – distance from the point of contact

  5. Calculations of the parameters of shock-compressed gas Initial data: detonation velocity explosive is 2400-3500 m/s,the ratio of the mass of the explosive to the mass of the cladding plate is 0.9 -1welding gap is 6-8 mm,welding angle is 11-13 degrees,throwing velocity is 400-600 m / s.Estimated values ​​of parameters in the chemical reaction zone of explosive: pressure is 1.2 GPa, temperature is 3000 - 4000 K The results of calculations:In the shock-compressed gas: the pressure of 7.12 MPa,temperature is 2700-5000 K,the length of shock-compressed gas at a distance of 6000 mm from the start of welding is 250 -300 mmIn marginal zone: the pressure is 0.1 MPa,temperature is 273-293 K Исходные данные: • скорость детонации взрывчатого вещества (ВВ) 2400-3500 м/с, • отношение массы ВВ к массе метаемой пластины 0,9 -1, • сварочный зазор 6-8 мм, • угол сварки 11-13 градусов, • скорость метания 400-600 м/с. Оценочные значения параметров в зоне химической реакции ВВ: давление 1-2 ГПа, температура 3000 - 4000 К Результаты расчётов: • В области УСГ: давление 7-12 МПа, • температура 2700-5000 К, • протяжённость области УСГ на расстоянии 6000 мм от начала сварки составляет 250 -300 мм • В краевых зонах: давление в области УСГ 0,1 МПа, • температура 273-293 К

  6. SPECIFICITY OF EXPLOSIVE WELDING IN MARGINAL ZONES The design scheme of explosion weldinga – width of the chemical reaction zoneh – the welding gapl– length of the shock-compressed gas area  – corner of WeldingVn – velocity of throwingD – detonation velocityVk – contact point velocity To ensure the stability of the process of explosion welding on the entire surface, including the marginal zone, you must set the parameters in the welding zone from the condition: K – The empirical coefficient

  7. Conclusions In marginal areas due to the sharp fall of shock-compressed gas parameters (temperature and pressure) in the cladding sheet shear stresses arise, which grow as you move the front welding, which leads to deformation of elongation in the direction of welding and the exhaustion of ductility of the metal cracking and damage. To ensure the stability of the process of explosion welding on the entire surface, including the marginal zone, you must set the parameters in the welding zone from the condition: • В краевых зонах вследствие резкого падения параметров области УСГ (температуры и давления) в плакирующем листе возникают напряжения сдвига, которые растут по мере продвижения фронта сварки, что приводит к появлению деформации удлинения в направлении сварки и при исчерпании пластичности металла образованию трещин и разрушений. • Для обеспечения стабильности процесса сварки взрывом на всей поверхности, включая краевые зоны, необходимо задавать параметры области УСГ в зоне сварки из условия:

  8. Marginal zone of bimetal obtained under the

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