DH36高强度钢摩擦柱塞焊工艺与接头组织性能

对高强度船体结构钢DH36钢板进行了摩擦柱塞焊工艺试验研究,对焊接接头微观组织、显微硬度、抗拉强度及连接界面处冲击吸收功进行了观察与测试,对连接界面处拉伸断口进行了扫描电镜观察.结果表明,采用优化摩擦柱塞焊工艺可成功实现DH36高强度钢和柱塞的冶金连接,焊缝区出现明显的硬化倾向,其显微硬度最高可达333 MPa;焊接接头抗拉强度高于母材,连接界面处拉伸断口具有微小等轴韧窝和解理断裂的混合特征,但接头连接界面处冲击吸收功为37 J±5 J,明显低于母材205 J.这是由于焊接热循环过程中在母材与柱塞连接界面附近产生了大量贝氏体及魏氏体铁素体组织导致的韧性降低造成的.

Microstructure and properties of friction hydro pillar processed DH36 high strength steel

Friction hydro pillar processing(FHPP) of DH36 high strength steel for ship structures was performed. The microstructure, hardness profile, tensile strength and Charpy impact value of FHPP welded joints were observed and tested. The tensile fracture surface along the FHPP bonding interface was examined by scanning electron microscope. It was verified that the metallurgical bonding between the pillar and DH36 base material can be successfully obtained under optimum welding parameters.The hardening tendency of FHPP weld was obvious and the highest hardness value reached 3.33 GPa. The tensile strength of FHPP welded joints was higher than that of DH36 base material, and the tensile fracture morphology in the interface between pillar and base material presented specific features blending small equiaxed dimples and cleavage fracture. But Charpy impact toughness around the bonding interface was only 37 J ± 5 J which was obviously lower than 205 J of the base metal. The large amounts of upper bainite produced around the bonding interface during FHPP reduced the impact toughness.