Q690抗震耐蚀钢埋弧焊熔敷金属性能研究

Research on the Mechanical Properties of Q690 Seismic and Corrosion Resistant Steel Submerged Arc Welding Deposited Metal

研究了道间温度、焊接热输入对Q690高强抗震耐蚀钢埋弧焊熔敷金属性能的影响,推荐出适合该钢的最佳埋弧焊工艺。当道间温度低于100℃,熔敷金属拉伸重复出现脆断现象,道间温度高于100℃未出现脆断,应用扫描电镜分析认为断口位置为氢致脆断,对缺陷中心夹杂物能谱分析,结果表明该夹杂物为非金属夹渣。通过控制焊接电流和焊接速度,研究焊接热输入对熔敷金属抗拉强度、屈服强度、延伸率、布氏硬度和冲击韧性的影响。除热输入为28.3 kJ/cm时,熔敷金属抗拉强度和屈服强度有所升高,随着热输入增大,熔敷金属拉伸性能总体呈下降趋势,热输入为21.6 kJ/cm熔敷金属冲击平均值最佳,布氏硬度随着热输入增大逐渐降低。推荐较佳的焊接热输入为19.8~21.6 kJ/cm,道间温度为100~200℃。

In this paper,the effects of interpass temperature and welding heat input on the properties of submerged arc welding deposited metal of Q690 high strength seismic and corrosion resistant steel are studied,and the best submerged arc welding process suitable for this steel is recommended.When the interpass temperature is lower than 100℃,the brittle fracture occurs repeatedly in the tensile of deposited metal,and there is no brittle fracture when the interpass temperature is higher than 100℃.SEM observation shows that the fracture position is hydrogen induced brittle fracture,the energy spectrum analysis of the inclusion in the defect center shows that the inclusion is non-metallic slag.By controlling the welding current and welding speed,the effects of welding heat input on the tensile strength,yield strength,elongation,Brinell hardness and impact toughness of deposited metal are studied.Except when the heat input is 28.3 kJ/cm,the tensile strength and yield strength of the deposited metal increase,with the increase in heat input,the tensile properties of the deposited metal generally show a downward trend,when the heat input is 21.6 kJ/cm,the average impact value of the deposited metal is the best,and the Brinell hardness decreases gradually with the increase in heat input.It is recommended that the better welding heat input is 19.8~21.6 kJ/cm and the interpass temperature is 100~200℃.