管线用自保护药芯焊丝低温韧性分析

Analysis on low temperature toughness of self-shielded flux cored wire used for pipeline

通过分析熔敷金属冲击断口宏观及SEM形貌、显微组织形态和定量统计夹杂物,研究三种市售X70管线用自保护药芯焊丝熔敷金属的低温韧性.结果表明,3号焊丝其熔敷金属-40℃冲击吸收功平均值高达330 J,而1号焊丝其熔敷金属-30℃冲击吸收功平均值仅为113 J.熔敷金属夹杂物和显微组织的不同是造成其韧性差异显著的主要原因.均匀弥散分布的细小夹杂物和均匀细小的等轴晶组织有利于提高熔敷金属的低温韧性.

Low temperature toughness of deposited metal made by three types self-shielded flux-cored wires used for X70 pipeline has been investigated,by analyzing macroscopic and SEM morphology of impact fracture,microstructure and statistics of inclusion.The results showed that low temperature toughness of deposited metal of three wires was significantly different.No.3 wire has highest toughness with an impact absorbing energy average value of 330 J at-40 ℃,while the toughness of No.1 wire is the lowest,whose impact absorbing energy average value is only 113 J at-30 ℃.Differences of inclusions and microstructure of deposited metal were the main reason for significantly different toughness.Uniform and fine equiaxed grains and small inclusions uniformly and dispersedly distributed in deposited metal are beneficial to improve the low temperature toughness.