L360QCS微合金钢焊接接头抗SSCC性能分析

经过反复焊接工艺试验,确定了合理的L360QCS微合金钢焊接工艺参数,针对L360QCS微合金钢焊接接头进行了抗SSCC试验研究。结果表明,焊接接头屈服强度为410 MPa,抗拉强度为528 MPa,平均冲击功值为145J,弯曲试验、刻槽锤断试验均未见缺陷,各类力学性能指标合格;根焊层、填充层、盖面层平均硬度值分别为136.6HV、146.3HV、157.1HV;根焊层、填充层微观组织晶粒细小,为等轴铁素体+珠光体盖,盖面焊层组织晶粒较粗大,为粒状贝氏体+珠光体+针状铁素体;焊接接头SSCC试验未出现裂纹,经XRD、SEM分析,腐蚀产物膜为呈堆砌状态的四方晶系晶体FeS。L360QCS微合金钢焊接接头能够满足NACE TM0177-2005标准规定的抗SSCC性能要求。

Performance Analysis of SSCC of Welded Joint of L360QCS Micro Alloyed Steel

After repeated welding process test, the reasonable welding process parameters was determined to L360QCS micro alloy steel. The analysis of SSCC was conducted on the welded joints of L360QCS micro alloy steel. The results show that the yield strength is 410 MPa, the tensile strength is 528 MPa. The average impact energy is 145 J. No defect is found by bending test and a grooving and hammer breaking test. Each mechanics performance indicators are all qualified. The average hardness value are 136.6HV, 146.3HV, 157.1HV in root, filling and cover surface layer. The tiny microstructure of root and filling layer are grain fine, equiaxed ferrite, pearlite cover. The massive microstructure of covering layer are granular bainite, pearlite, acicular ferrite. There is no cracking on welded joint of SSCC. XRD, SEM results indicate that the corrosion product film is stack-type FeS of tetragonal system. The welding joint of L360QCS micro alloy steel is qualified to prevent SSCC by NACE TM0177-2005 standard.