材料强度对爆炸焊接结合界面的影响

为了研究爆炸焊接结合界面机理及材料强度对爆炸焊接的影响,采用相同的爆炸焊接参数对不同强度的基板进行了爆炸焊接。通过光学显微镜、扫描电子显微镜以及数值模拟技术对焊接试样的形貌、缺陷以及焊接机理进行了分析。结果表明:当材料强度较低时,碰撞点动压与基板材料强度的比值较高,界面出现较大的塑性应变并生热,此时界面熔化区较大,在焊接过程中可以将界面等效为不可压缩流体;当材料强度较高而碰撞点动压与基板强度的比值较低时,试样界面形貌受材料强度的影响较大。随着材料强度的上升,周期性的波状界面逐渐趋于平直。界面熔化现象减弱但温升速率较高,并受碰撞点附近高压出现热失稳现象形成剪切带及裂缝。此时材料强度的影响不可忽略,界面不能等效为不可压缩流体。

Interface characteristics of explosive welding for different strength plates

This work studies the effect of base plate initial tensile strength on interface morphology and welding quality in explosive welding. The plates with different initial tensile strength were fabricated via explosive welding method under the same parameters. The microstructure of the interface for the explosive welding sample was analyzed, and the results showed that the interface of the explosive welding sample was greatly influenced by the strength of the material, the interface was formed of over-melted, periodic ripples and finally flattening with the increasing strength of the material. Combined with the numerical simulation results, it is found that the interface melting zone is large and can be considered as an incompressible fluid for analysis when the specific pressure of explosive welding is high. When the specific pressure is low, the local temperature rising speed of the welded sample will be higher and the adiabatic shear zone will be formed under the action of plastic strain, although the interface will still melt. The strength of the material cannot be neglected for the explosive welding.