| Explosion welding is an efficient welding method that can make dissimilar metals composite,and its products are widely used in aerospace,marine,chemical and other fields.Copper / steel composite plate is widely used in engineering,copper / steel composite plate can not only save the use of copper,but also can combine the advantages of the two metals.But the current explosion welding is often carried out in remote mountainous areas,which not only increases the cost of transporting materials,and explosion welding operations will cause irreversible harm to the surrounding environment;while atmospheric pressure explosion welding bonding surface oxide is the main reason for microscopic defects in the composite plate.The construction of vacuum explosion welding workshop can not only reduce the cost of transportation and explosion generated by vibration,noise,but also by reducing the content of the bonding surface oxide to improve the microscopic defects of the composite plate.This article for T2/Q235 for negative pressure explosion welding research,through its interface microscopic observation,mechanical properties testing and numerical simulation to verify the way for the vacuum explosion welding engineering applications to provide theoretical guidance,in order to achieve the factory and urbanization of explosion welding.The main conclusions of the article are as follows:(1)produced a special powdered emulsified explosive for explosion welding and its explosive properties under different environmental pressure conditions explored.In the traditional process based on the use of diatomaceous earth on the emulsion matrix for physical sensitization,through cooling,sieving to produce a special powdered emulsion explosives for explosive welding,the explosive particle size of 60 mesh,from a macroscopic view of this explosive particles uniform,good dispersion,non-binding.The explosive in the negative pressure conditions of the explosive density will become larger.Explosive performance test results show that: the negative pressure conditions of the explosive welding special explosives burst speed and fierce than under normal pressure conditions are increased,and under different conditions the explosive burst speed,fierce moderate,can be used as an explosive welding agent.(2)in different environmental pressure conditions for T2/Q235 explosion welding experiments,and its interface for microscopic observation and oxygen element analysis.Explosion welding experimental flaw detection results show that T2/Q235 are fully composite;metallographic interface shows: negative pressure environment explosion welding interface wave than atmospheric conditions;energy spectrum element results show that: negative pressure conditions are conducive to reducing the oxygen element of the bonding surface;in 0.2 atm conditions for different plate spacing explosion welding experiments.The results show that: different plate spacing the same plate spacing conditions,with the reduction of ambient pressure,T2/Q235 bond surface wave height and wavelength are increased.In 3mm atmospheric pressure conditions,T2/Q235 explosion composite plate bond surface does not appear stable periodic waveform,indicating that the plate spacing conditions,the collision speed of the cladding is not enough and thus lead to T2/Q235 composite quality is not good.In the plate spacing of 9mm conditions,although there is a good waveform,but the three plate spacing conditions under the wave size is relatively close to the vacuum conditions of the explosion welding does not reflect its advantages.In the upper limit of the explosion welding window,the negative pressure conditions have little effect on the explosion welding;in the lower limit of the explosion welding window,the negative pressure conditions can significantly improve the energy utilization of the explosion welding.(3)mechanical properties of T2/Q235 composite plate obtained under different pressure environmental conditions.The results show that the average thickness of the explosion-welded T2/Q235 composite plate gradually decreases as the ambient pressure decreases,proving that the composite plate is compressed more significantly under negative pressure conditions.T2/Q235 explosion composite plate under negative pressure conditions,tensile strength,bond strength,cut-off strength are better than normal pressure,but the plasticity of the material under negative pressure conditions will become worse;through the wavelength of the bond surface arc differential,the length of the bond surface curve,from the theoretical explanation of the negative pressure conditions of the material bonding higher than normal pressure;0.2atm conditions,T2/Q235 explosion welding best plate spacing in the vicinity of 6 mm.(4)from theoretical and numerical simulation analysis of the relationship between the flight speed and environmental pressure in the explosion welding cladding: the change in vacuum does not affect the state of motion of the explosion welding cladding,three pressure conditions of the explosion welding collision speed,collision pressure is not significantly different;different densities of emulsified explosives for the simulation of the explosion welding results show that: with the increase in explosive density,the explosion welding cladding plate Collision speed and collision pressure increase,the simulated waveform and experimental trends match,indicating that the negative pressure conditions of the explosive is through the increase in density to change the process of explosive welding.Negative pressure conditions of explosive welding can improve the energy utilization of powdered emulsion explosives;simulation of different plate spacing under negative pressure conditions,the results show that: with the increase in plate spacing,the movement of the cladding plate speed gradually increased,greater collision velocity will produce a larger waveform,and experimental values match,the collision velocity increases gradually and slowly after the plate spacing of 4mm.Figure[67] Table[16]... |
