ZG28NiCrMo与16Mn异种钢手工电弧焊接头组织及性能研究

Microstructure and Properties of ZG28NiCrMo and 16Mn Dissimilar Steel Electrode Welding Joint

采用A307焊条对ZG28Ni Cr Mo铸钢和16Mn低合金高强钢进行了手工电弧焊,通过金相分析,拉伸、冲击及显微硬度测试研究了异种钢焊接接头的组织及力学性能。结果表明,焊缝中心组织为奥氏体＋铁素体;ZG28Ni Cr Mo钢一侧熔合区形成脱碳层和柱状晶区,使显微硬度值显著下降;ZG28Ni Cr Mo钢侧热影响区的组织为铁素体＋珠光体组织,与其母材相比有软化现象。16Mn侧热影响区没有硬度损失,16Mn钢与焊缝的熔合线处存在一层奥氏体单相区,硬度为220HV,高于焊缝中心和16Mn钢母材。焊接接头拉伸断裂于16Mn母材处,平均抗拉强度为515MPa。ZG28Ni Cr Mo钢侧热影响区的冲击韧性较差,而16Mn侧热影响区的冲击韧性优于焊缝中心。

ZG28 Ni Cr Mo cast steel and 16 Mn low alloy high strength steel were welded by using electrode welding and A307 electrode. The microstructure and mechanical properties of dissimilar steel welded joint were investigated by metallographic analysis and tensile, impact and microhardness tests. The results show that the microstructure of the weld center consists of austenite and ferrite. The decarburization layer and columnar zone form in the fusion zone at the side of ZG28 Ni Cr Mo steel, and the microhardness values significantly reduce. The microstructure of HAZ at the side of ZG28 Ni Cr Mo steel is ferrite and pearlite, and there is softening phenomenon compared with the base metal. There is no hardness loss in the HAZ at the side of 16 Mn steel. There is a single austenite zone between 16 Mn steel and weld＇s fusion line,and the hardness of the zone is 220 HV, which is higher than that of weld center and 16 Mn steel base material. The weld joint is broken at the 16 Mn base metal, and the average tensile strength of the joints is 515 MPa. The impact toughness of HAZ at the side of ZG28 Ni Cr Mo steel is poor, but the impact toughness of HAZ at the side of 16 Mn steel is better than that of weld center.