低焊接裂纹敏感性钢焊接接头组织及微观力学性能  

Structure and Micromechanical Properties of a Weld Joint Using Steel with Low Sensitivity to Weld Cracking

作　　者：兰亮云[1] 邱春林[1] 赵德文[1] 高秀华[1] 

机构地区：[1]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：《东北大学学报（自然科学版）》2011年第4期505-508,共4页Journal of Northeastern University(Natural Science)

基　　金：中央高校基本科研业务费专项资金资助项目(N100607001);国家自然科学基金资助项目(51074052)

摘　　要：采用埋弧自动焊接方法焊接高强度低焊接裂纹敏感性钢板,并对其焊接接头进行显微组织观察、维氏显微硬度和纳米压痕检测.结果表明:粗晶热影响区的显微组织以粗大粒状贝氏体为主,由于该区的精细结构中含有大量纳米级析出相,且位错密度较高,使得该区具有较高的维氏显微硬度和纳米硬度值;焊缝区和细晶热影响区的主要显微组织分别为针状铁素体+先共析铁素体和准多边形铁素体,二者的纳米硬度和弹性模量值均小于粗晶热影响区的纳米硬度和弹性模量,表明粗晶热影响区的微观强度最高;粗大贝氏体组织可能会恶化粗晶热影响区的冲击韧性而导致焊接接头出现局部脆性断裂.Submerged arc welding technology was used to weld a steel plate with low susceptibility to weld cracking,and microstructure observation,conventional Vickers microhardness and nanoindentation examination were conducted in the heat affected zone（HAZ）.The results show that a coarse grained HAZ mainly consisted of coarse granular bainite.Owing to a large number of nanoprecipitates and higher dislocation density,the higher microhardness and nanohardness were obtained in the coarse grained HAZ.The weld zone and fine grained HAZ mainly consisted of acicular ferrite plus proeutectoid ferrite and quasi-polygonal ferrite,respectively,and their nanohardness and modulus of elasticity were both less than that of the coarse grained HAZ.The greatest strength was observed in the coarse grained HAZ.The coarse granular bainite may diminish impact toughness,causing localized brittle fractures in the head of the coarse grained HAZ.

关 键 词：低焊接裂纹敏感性钢 热影响区 纳米硬度 弹性模量 贝氏体 

分 类 号：TG401[金属学及工艺—焊接]