采用Gleeble 3500型热模拟试验机对X80管线钢进行模拟，制定出了X80管线钢的模拟焊接热影响区连续冷却转变(SHCCT)曲线，分析了显微组织和硬度随冷却速率的变化情况。结果表明：X80管线钢的冷裂纹敏感性指数小于0.2%，具有低焊接裂纹敏感性，焊接工艺的预热温度应控制在47 ℃以上，且应避免在较快的冷却速率下焊接。经过热模拟后对X80管线钢冲击吸收能量和SHCCT曲线的初步推断，X80管线钢焊接时较合理的热输入为10～20 kJ·cm^-1。

X80 pipeline steel was simulated by Gleeble 3500 thermal simulation test machine, the simulated welding heat affected zone continuous cooling transformation (SHCCT) curve of X80 pipeline steel was formulated, and the changes of microstructure and hardness with cooling rate were analyzed. The results show that the cold crack sensitivity index of X80 pipeline steel was less than 0.2%, which had low welding crack sensitivity. The preheating temperature of welding process should be controlled above 47 ℃, and welding at fast cooling rate should be avoided. According to the preliminary inference of impact absorbed energy and SHCCT curve of X80 pipeline steel after thermal simulation, the more reasonable heat input during welding of X80 pipeline steel was 10-20 kJ·cm^-1.