低碳贝氏体钢双面埋弧焊接头的组织和低温韧性-材料研究学报.PDF

第29 卷 第10 期 材 料 研 究 学 报 Vol. 29 No. 10 2 0 1 5 年 1 0 月 CHINESE JOURNAL OF MATERIALS RESEARCH October 2 0 1 5 低碳贝氏体钢双面埋弧焊接头的组织 和低温韧性* 张 敏 任晓龙 邢 奎 李继红 (西安理工大学材料科学与工程学院 西安 710048) 摘要对低碳贝氏体钢进行双面埋弧焊焊接, 并用光学显微镜和PSW750 型示波冲击试验机对焊接接头进行表征, 研究了钢 的显微组织和低温韧性。结果表明: 低碳贝氏体钢双面埋弧焊后, 焊缝区的组织为针状铁素体和粒状贝氏体; HAZ 的组织 为贝氏体铁素体和粒状贝氏体; HAZ 熔合线附近的硬度最高, 远离熔合线硬度降低并逐渐接近母材金属的硬度; 随着温度 的降低焊接过程中的凝固偏析、高度集中的位错源来不及松弛应力集中以及分布在晶界上的Ti、Mo 等微合金元素形成的碳 氮化物, 导致焊接接头焊缝区和HAZ 韧性降低并在-20 ℃和-60℃发生韧脆转变。 关键词 金属材料, 低碳贝氏体钢, 埋弧焊, 显微组织, 低温韧性 分类号 TG407 文章编号 1005-3093(2015) 10-0737-07 Microstructure and Low Temperature Toughness of Weld Joints Prepared by Double-sided Submerged Arc Welding for Low Carbon Bainite Steel ZHANG Min** REN Xiaolong XING Kui LI Jihong (College of Material Science and Engineering, Xi’an University of Technology, Xi ’an 710048, China) *Supported by Natural Science Foundation of China No National High Technology Research and Devel- opment Program and the Science and Technology Program of Xi ’an No.CX 12136. Manuscript received July 22, 2014, in revised form April 30, 2015. **To whom correspondence should be addressed, Tel(029 E-mail: zhmmn@xaut.edu.cn ABSTRACT The low carbon bainite steel was welded by double-sided submerged arc welding and the microstructure and low temperature toughness of the joints was studied by optical microscope and PSW750 instrumented impact testing machine. The results show that the microstructure of the weld seam consisted of acicular ferrite and granular b