保护气体对1.4003不锈钢焊接接头组织和疲劳性能的影响

CO2与O2作为MAG焊接时常用的活性气体,对1.4003不锈钢接头的金相组织与疲劳性能有不同的影响。通过金相组织分析和脉动拉伸疲劳试验,研究两种保护气氛下1.4003钢MAG焊接头的组织和疲劳性能。结果表明:两种接头焊缝组织的基体均为奥氏体,基体上分布δ铁素体;当保护气体为φ(Ar)95%+φ(CO2)5%时,中值疲劳强度为312.5 MPa;当保护气体为φ(Ar)97%+φ(O2)3%时,中值疲劳强度为302.5 MPa。两种保护气体的疲劳试件断裂位置主要集中在热影响区,均有明显的启裂源,扩展区疲劳纹清晰,终断区形态为韧窝型韧性断口。

Effect of protective atmosphere on microstructure and fatigue performance of 1.4003 stainless steel welded joints

The oxygen and carbon dioxide are available active gas and both are applied to MAG,and have different influence on the mechanical properties and microstructure of stainless steel.Through pulsating tensile fatigue test and microstructure analysis,studied that the microstructure and fatigue performance of MAG welding butt joint of 1.4003 steel under two kind of protective atmospheres.The results show that,the microstructure of base metal of two welds are both austenitic,and the δ ferrite are on the matrix;the median fatigue strength of φ(Ar)95％+φ(CO2)5％ is 312.5 MPa,the median fatigue strength of φ(Ar)97％+φ(O2)3％ is 302.5 MPa.The fracture location of specimen is mainly concentrated in the heat affected zone.The crack starter location is obvious on the crack initiation zone,the fatigue beach on the extending zone is vivid,the final broken zone is the toughness fracture of dimple type.