Q235B/SUS304螺旋冶金复合管埋弧焊接头的组织和性能  

Study on microstructure and properties of Q235B/SUS304 spiral metallurgy composite pipe welded joint by submerged arc welding

作　　者：刘云 杨军 Liu Yun;Yang Jun(Chinese National Engineering Technology Research Center for Petroleum and Natural Gas Tubular Goods,Baoji 721008,Shaanxi,China;Steel Pipe Research Institute of Baoji Petroleum Steel Pipe Co.,Ltd.,Baoji 721008,Shaanxi,China;Shaanxi Railway Institute,Weinan 714000,Shaanxi,China)

机构地区：[1]国家石油天然气管材工程技术研究中心,陕西宝鸡721008 [2]宝鸡石油钢管有限责任公司钢管研究院,陕西宝鸡721008 [3]陕西铁路工程职业技术学院,陕西渭南714000

出　　处：《焊接》2019年第10期38-46,51,I0004,共11页Welding & Joining

基　　金：国家863计划(2013AA031303);陕西省科技统筹创新工程计划(2014KTDZ01-03-02)

摘　　要：采用埋弧焊接(SAW)工艺对规格为φ610 mm×(6+1)mm的Q235B/SUS304螺旋冶金复合管(基层碳钢厚6 mm,复层不锈钢厚1 mm)进行了试制生产试验。利用OM,SEM研究了复合管焊接接头各区微观组织特征,并测试了焊接接头力学性能和耐腐蚀性能。结果表明,研究开发的埋弧焊接工艺能有效抑制合金元素稀释,使得复合管复层焊缝金属合金成分保持在合理水平。复层焊缝金属微观组织为针片状奥氏体+条带状或蠕虫状铁素体,基层焊缝金属区微观组织为少量先共析铁素体+细小针状铁素体,碳钢焊缝热影响区(HAZ)为粗大魏氏体组织。试制复合管焊接接头抗拉强度平均值为478 MPa,0℃下焊缝和HAZ冲击吸收能量平均值分别为110 J和134.7 J;焊接接头正弯、背弯(弯轴直径d=35 mm)180°拉伸面无裂纹;高硬度值点分布于焊缝金属区,不锈钢侧硬度值处于244~297 HV10,碳钢侧硬度值则处于149~232 HV10。晶间腐蚀试验和电化学腐蚀试验结果表明,复合管复层焊缝具有优良耐腐蚀性能,电化学腐蚀速率为5.14×10^-4 mm/a,约为母材的60%。The submerged arc welding(SAW)process for production experiment was carried out on Q235B/SUS3 spiral-metallurgy clad pipe with size of φ610 mm×(6+1)mm(matrix Q235B steel with 6 mm thickness,cladding SUS304 with 1 mm thickness).Microstructures of composite pipe’s welded joints were studied by OM and SEM,and mechanical properties and corrosion resistance of welded joints were tested.The results showed that the submerged arc welding process developed in this study could effectively inhibit the dilution of alloy elements,which kept composition of composite pipe cladding weld metal at a reasonable level.Microstructures of the cladding weld were elongated and flaky austenite+strip or worm-like ferrite,microstructures of matrix weld were a small amount of pro-eutectoid ferrite+fine acicular ferrite,and microstructures of carbon steel weld heat affected area(HAZ)were coarse widmannstatten structure.The average tensile strength of clad pipe welded joint was 478 MPa,and the average impact energy of weld and HAZ at 0℃were 110 J and 134.7 J,respectively.Welded joints were face and root bent 180°(bend diameter d=35 mm),and tensile surface had no cracks.Points with high hardness values distributed in the weld metal zone.Hardness value in the stainless steel side was 244~297 HV10,while the hardness value in the carbon steel side was 149~232 HV10.The results of intergranular corrosion test and electrochemical corrosion test showed that the cladding weld of the composite pipe had excellent corrosion resistance and the electrochemical corrosion rate was 5.14×10^-4 mm/a,which was about 60%of that of the parent material.

关 键 词：Q235B/SUS304 螺旋冶金复合管 埋弧焊 晶间腐蚀 电化学腐蚀 

分 类 号：TG442[金属学及工艺—焊接]