不同焊接工艺对DH36钢板接头组织及性能的影响

Effect of different welding process on microstructure and properties of welded joint of DH36 plate

针对25 mm厚的DH36钢板,采用焊条电弧焊+埋弧焊(SMAW+SAW)、CO_(2)气体保护焊+埋弧焊(FCAW+SAW)、焊条电弧焊+CO_(2)气体保护焊(SMAW+FCAW)3种焊接方法完成焊接,通过对比焊后接头试样的微观组织、硬度、拉伸性能得知:3种焊接工艺均满足AWS D1.1—2015标准要求。其中,FCAW+SAW接头的力学性能为最优,SMAW+FCAW方案的次之,SMAW+SAW方案由于焊缝区先共析铁素体较多,且热影响区组织相对粗大,导致热影响区硬度偏高,冲击吸收功较低,焊缝区硬度相对较低,因此该方案相对最差。考虑到FCAW+SAW方案焊接质量较稳定,焊接速度相对较高,建议采用FCAW+SAW方案完成DH36钢板的焊接。

Three welding methods,manual arc welding+submerged arc welding( SMAW+SAW),carbon dioxide gas shielded welding +submerged arc welding( FCAW +SAW),manual arc welding +carbon dioxide gas shielded welding( SMAW+FCAW) were used to weld the DH36 steel plate with a thickness of 25 mm.The microstructure,hardness and tensile properties of the welded joints samples were compared.The three welding processes met the requirements of AWS D1.1—2015 standard.Among them,FCAW+SAW had the best mechanical properties,SMAW+FCAW scheme took the second place.In SMAW+SAW scheme,there were more proeutectoid ferrite in the weld area and the microstructure in the heat affected zone was relatively coarse,resulting in high heat affected hardness value,low impact value and relatively low hardness value in the weld area.Therefore,this scheme was relatively the worst.Considering the welding quality of FCAW+SAW scheme was relatively stable and the welding rate was relatively high,it was suggested that FCAW+SAW scheme should be adopted to complete the welding of DH36 steel plate.