冷却工艺对X80HD2管线钢组织和性能的影响

Effect of Cooling Process on the Microstructure and Properties of X80HD2 High Strain Pipeline Steel

试验分析了开冷温度、冷却速度和终冷温度对X80HD2管线钢组织和性能的影响,结果表明,在不同开冷温度下,均能得到铁素体和贝氏体双相组织,随开冷温度的降低,铁素体含量增多,M/A含量增加,屈服强度下降,Rt0.5/Rm下降,均匀伸长率降低;随冷却速度提高,贝氏体组织细化,屈服强度增加,Rt0.5/Rm升高,均匀伸长率降低;随终冷温度降低,M/A细化,抗拉强度降低,Rt0.5/Rm升高,加工硬化速率升高,均匀伸长率升高。最佳冷却工艺参数:开冷温度690℃,冷却速度15℃/s,终冷温度400℃。

The influence of cooling temperature, cooling rate and final cooling temperature on the microstructure and properties of XSOHD2 pipeline steel were analyzed. The results showed that： in different cold temperatures, the ferrite and bainite dual phase microstrueture were obtained. But with decreasing of the cooling temperature, although the ferrite content and the content of M/A increased, the yield strength, Rt0.5/Rm and uniform elongation decreased. With increasing of the cooling rate, the bainite refined, yield strength, Rt0.5/Rm increased, and the uniform elongation decreased. With decreasing of the final cooling temperature, the M/A island refined, tensile strength,Rt0.5/Rm, dσ/dε and uniform elongation increased. The optimum cooling process parameters are： the start cooling temperature is 690 ℃, the cooling rate is 15℃/s and the final cooling temperature is 400 ℃.