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利用热电偶测出X80管线钢SMAW(手工电弧焊)和GMAW(熔化极气体保护焊)的焊接热循环,结合金相组织分析、焊接热影响区最高硬度试验方法和焊接用插销试验方法,研究不同热循环对X80管线钢冷裂敏感性的影响。结果表明,随冷却速度增加,下贝氏体增多,硬度增大,无马氏体出现;最高硬度H max远低于350 HV10,且下临界应力σcr>0.75R t0.5,说明X80管线钢具有良好的抗冷裂纹能力。
The thermocouple was used to measure the welding thermal cycle of SMAW (manual arc welding) and GMAW (molten metal arc welding) of X80 pipeline steel. Combined with the microstructure analysis, the maximum hardness test method of HAZ and the test method of welding bolt, Effect of Different Thermal Cycling on Cold Crack Sensitivity of X80 Pipeline Steel. The results show that as the cooling rate increases, the lower bainite increases and the hardness increases without martensite. The maximum hardness H max is much lower than 350 HV10 and the lower critical stress σcr is 0.75 R t0.5, which indicates that X80 pipeline steel Has good resistance to cold cracking.