摘要
采用焊条电弧焊、CO2气体保护焊焊接了控扎控冷制备输电铁塔用细晶Q420低合金高强钢。研究焊接接头显微组织和力学性能,并对比分析热轧制备Q420钢焊接接头的冲击韧性。研究结果表明,选择E5515焊条、ER55-G焊丝焊接所得细晶Q420高强钢焊接接头焊缝金属主要由铁素体和少量珠光体构成,ER55-G焊丝由于添加Ti元素获得了较多针状铁素体。拉伸试验结果表明,焊接接头断裂于母材位置,焊缝具有比母材更高的强度。焊缝金属的显微硬度高于母材,接头热影响区未出现软化现象。相比较热轧制备Q420高强钢,控扎控冷制备细晶Q420钢焊接接头冲击韧性更高,更加适宜于具有较高低温韧性要求的输电铁塔制造。
Ultra-fine grained Q420 steel manufactured by TMCP was welded by means of shielded metal arc welding and CO2 gas metal arc welding.Microstructure and mechanical properties of the welded joint were investigated,and impact toughness of hot rolled Q420 steel joint was also analyzed.Results show that using E5515 electrode and ER55-G welding wire,weld metal consists of ferrite and pearlite with little amount.The presence of acicular ferrite in the weld metal fabricated by ER55-G welding wire is attributed to the addition of Ti in it.Tensile test showed that the specimen fractured at the base metal,indicating the strength of the weld metal is higher than that of the base metal. Microhardness of the weld metal is higher than that of the base metal and soft phenomenon was not observed for the HAZ of the welded joint.In comparison to Q420 steel fabricated by hot rolling,welded joint of fine-grained steel shows high toughness and thus it is more suitable for being used for electric transmission tower that requires high impact toughness at low temperature.
出处
《电焊机》
北大核心
2011年第12期39-43,共5页
Electric Welding Machine
关键词
细晶钢
焊接
显微组织
力学性能
fine-grained steel
welding
microstructure
mechanical properties
