X65管线钢板交替与连续控冷工艺的计算与比较

为减小X65管线钢板控制冷却后的残余应力和翘曲,通过开发线性混合热膨胀模型、拓展Avrami相变动力学模型和应用Leblond的相变诱发塑性(TRIP)模型建立了热力耦合有限元模型,考虑了控冷时的弹塑性变形、热膨胀、相变潜热、相变膨胀、TRIP等所有物理效应.用该模型研究了2种控制冷却工艺下X65管线钢板的温度、残余应力、残余应变及翘曲.结果表明:与连续控冷相比,交替控冷使板的温度进一步降低7℃；上表面一侧的残余拉应力峰值进一步减小44 MPa；下表面一侧的残余总压应变峰值进一步增加0.001；翘曲由0.54×10-3减至0.09×10-3；故交替控冷可降低板内的残余应力,并减小翘曲.

Calculation and comparison between alternate and continuous controlled cooling technology for X65 pipeline steel plate

To decrease the residual stress and warping of X65 pipeline steel plate after controlled cooling,a thermo-mechanical coupled FEM model was established according to linear mixture thermal expansion model,modified Avrami transformation dynamics model and Leblond transformation induced plasticity(TRIP) model.All relevant physical effects of elastoplastic deformation,thermal expansion,latent heat,transformation dilatation and TRIP effect were considered in the FEM model.Temperature,residual stress,residual strain and warping of X65 pipeline steel plate were analyzed by the proposed model under two controlled cooling technologies.The results show that the temperature of plate under alternate controlled cooling is 7 ℃ less than that under continuous controlled cooling.The residual tensile stress peak value near top surface is decreased by 44 MPa with enhanced residual compressive strain peak value of 0.001 near bottom surface,while the warping is reduced from 0.54×10-3 to 0.09×10-3.Alternate controlled cooling can reduce residual stress and warping of plate.