Abstract:  With the increase of the proportion of hot delivery and hot charging in pipeline steel continuous casting slab， the cut continuous casting slab are prone to quality defects due to the coupling effect of phase transformation， thermal stress， and temperature， resulting in huge economic losses.This article takes X70 pipeline steel as the research object，by comprehensively considering the nonlinear changes of material thermal properties parameters with temperature and the setting of boundary conditions， the ABAQUS finite element analysis software is used to conduct thermal coupling numerical simulation analysis on the cooling process of X70 pipeline steel 4 500 mm × 2 300 mm × 300 mm continuous casting slab. The conclusion shows that the average heat dissipation rate of the center of gravity of the slab is 0.076 ℃/s， the surface center is 0.084 ℃/s， and the temperature difference between the surface and the center is between 100 ℃ and 210 ℃， which gradually decreases over time. The stress value at the edge of the slab is 25 MPa， and the thermal stress within 300 mm of the edge is roughly the same， within 200 MPa. Considering the changes in temperature field， the cutting time to the heating furnace should be shortened as much as possible， or insulation measures should be added to prevent quality defects caused by excessive thermal stress.

Key words: Continuous Casting Slab, Thermo-Mechanical Coupling, Cooling, Temperature Field, Stress Field, Numerical Simulation

摘要： 随着管线钢连铸板坯热送热装占比的升高，切割后的连铸板坯在相变、热应力以及温度的耦合作用下易形成质量缺陷，造成巨大的经济损失。以X70管线钢为研究对象，通过综合考虑材料热物性参数随温度的非线性变化及边界条件的设定，利用ABAQUS有限元分析软件对X70管线钢4 500 mm×2 300 mm×300 mm连铸板坯的单坯冷却过程进行热力耦合数值模拟分析。结果表明，铸坯重心平均散热速率为0.076 ℃/s，表面中心为0.084 ℃/s，表面与心部温差区间为100~210 ℃，并随着时间逐步减小。铸坯边部应力值为25 MPa，边部300 mm以内热应力大致相同，在200 MPa以内。结合温度场变化情况应尽量缩短切割到加热炉的时间，或增加保温措施以防止因热应力过大形成质量缺陷。

关键词: 连铸板坯, 热力耦合, 冷却, 温度场, 应力场, 数值模拟