材料硬度对于水下爆炸焊接界面的影响

Effect of materials hardness on interfacial feature of underwater explosive welded joint

利用水下爆炸焊接方法,分别对初始态和硬化态工具合金钢与铜箔进行焊接试验.目的一,验证水下爆炸焊接法对于高硬度、超薄等难焊材料的焊接优势.目的二,对比两组试验,在相同材料成分,相同焊接参数下,可以研究材料初始硬度对爆炸焊接结果的影响.微观组织显示界面为连续的波纹形态.初始态工具钢和铜箔都显示硬度在界面处稍有增加,唯独在淬火硬化态工具钢焊接后出现硬度明显下降.金相组织观察,初始态合金工具钢在碰撞点处的细晶强化和高密度位错导致硬度增加,而淬火硬化态合金钢在界面处奥氏体化相变是导致硬度降低的主要原因.

In this paper,both as-received tool steel and heat-treated tool steel were used for underwater explosive welding,which had two objectives: to investigate the possibility of welding a super-high hardness material with a thin copper foil using underwater explosive welding,and to investigate the effect of initial hardness on the bonding interface of identical compositional materials( with only hardness varying) under identical welding conditions. The microstructure and hardness at interface of the welded metals were evaluated. The hardness of as-received tool steel and copper increases near the interface and approaches a peak value followed by a gradual decrease away from the interface. This indicates that the microstructure near the interface was modified by the severe plastic deformation and cold working of the surfaces of the materials during the collision of the plates. It is interestingly found that a decrease of the hardness was seen in the case of quenched martensitic tool steel,which was absolutely different with the previous research on explosive welding. It was proved that it is the transformation from martensite phase s to ferrite phase in quenched tool steel that caused the decrease of hardness.