海洋平台用中锰钢气保焊接头组织与性能分析  

Analysis of microstructure and properties in gas shielded arc welded joint of medium-Mn steel for offshore platform

作　　者：齐祥羽 严玲 王东旭 杜林秀[4] QI Xiangyu;YAN Ling;WANG Dongxu;DU Linxiu(State Key Laboratory of Metal Material for Marine Equipment and Application,Anshan 114009,Liaoning,China;Iron and Steel Research Institute of ANGANG Group,Anshan 114009,Liaoning,China;ANGANG Steel Company Limited,Anshan 114042,Liaoning,China;State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,Liaoning,China)

机构地区：[1]海洋装备用金属材料及其应用国家重点实验室,辽宁鞍山114009 [2]鞍钢集团钢铁研究院,辽宁鞍山114009 [3]鞍钢股份有限公司,辽宁鞍山114042 [4]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819

出　　处：《钢铁研究学报》2025年第2期248-257,共10页Journal of Iron and Steel Research

摘　　要：为研究海洋平台用低碳中锰高强钢的焊接性能,对试验钢板进行了对接焊实验,借助拉伸试验机和摆锤冲击试验机分别检测了焊接接头的室温拉伸性能和低温冲击韧性。结果表明:试验钢板焊接接头拉伸试样于母材处断裂,焊缝金属强度高于母材;焊缝金属、粗晶热影响区、细晶热影响区、临界热影响区和母材各个区域的维氏硬度平均值分别为324 HV、379 HV、402 HV、353 HV和278 HV。由于马氏体组织的强化作用,热影响区中各亚区与母材相比均为局部硬化区。焊缝中心、熔合线、熔合线外侧1 mm、熔合线外侧3 mm和熔合线外侧5 mm处的-40℃低温冲击吸收功分别为67、46、51、70和92 J。焊缝的显微组织由大量纵横交错、彼此咬合的针状铁素体和少量高密度大角晶界的多边形铁素体组成,提高了裂纹形成功和裂纹扩展功,因而焊缝具有较高的低温冲击韧性。熔合线处存在微观组织突变,显微组织是由板条马氏体、针状铁素体和少量粒状贝氏体组成的混合组织。粗晶热影响区的再结晶晶粒尺寸粗大,大角晶界密度较低,在一个马氏体板条块内部存在大量相互平行的粗大马氏体板条,降低了裂纹扩展阻力,从而恶化了低温韧性。To study the welding performance of low-C medium-Mn high-strength steel for offshore platforms,butt welding experiments were conducted on the test steel plates.The tensile properties and low-temperature impact toughness of welded joints were tested by a tensile testing machine and a pendulum impact testing machine,respectively.The results showed that the tensile test specimen of the welded joint fractured at the base metal,and the strength of the weld metal was higher than that of the base metal.The average Vickers hardness values of weld metal,coarse-grained heat-affected zone,fine-grained heat-affected zone,intercritical heat-affected zone and base metal are 324 HV,379 HV,402 HV,353 HV and 278 HV,respectively.Sub-regions in heat-affected zone are all local hardening zone compared to the base metal,due to the strengthening effect of the martensite structure.The impact absorbed energy of weld seam center,fusion line,1 mm outside the fusion line,3 mm outside the fusion line and 5 mm outside the fusion line at-40℃is 67,46,51,70 and 92 J,respectively.The microstructure in the weld metal consists of a large amount of interlocked pattern acicular ferrite and a small amount of fine polygonal ferrite with high density of high misorientation boundaries,which improves the crack formation and propagation energy and lead to relatively high toughness in the weld metal.The fusion line has a mixture microstructure,which contains lath martensite,acicular ferrite,and little granular bainite.The microstructure shows abrupt change in fusion line.In the coarse-grained heat-affected zone,the microstructure consists of coarse martensite lath parallel to each other in large martensite packets with low density of high misorientation boundaries due to the large crystallographic grain size,which decreases the crack propagation resistance,thereby deteriorating the low-temperature impact toughness.

关 键 词：690 MPa级 中锰高强钢 焊接 低温韧性 维氏硬度 

分 类 号：TG442[金属学及工艺—焊接]