X65厚管线板控冷时的相变潜热及TRIP效应

摘要

通过开发线性混合热膨胀模型、使用Leblond相变诱导塑性（TRIP）模型和拓展Avrami相变动力学模型建立了热力耦合有限元模型,考虑了相变潜热、相变膨胀、TRIP效应、热膨胀等机制.用该模型分析了X65厚管线板从860℃至低温的非对称（上下表面层流冷却系数分别为3,1mW/mm2K）控冷过程,定量研究了相变潜热、TRIP效应对温度、残余应力的影响.结果表明：相变期间,潜热升温52.7℃,并减缓下表面和心部的温降分别为50%,25%;控冷终了,潜热提高板温44℃.潜热和TRIP效应分别产生峰值为±89M%Based on the developed linear mixture thermal expansion model,the Leblond transformation induced plasticity（TRIP）model,and the modified Avrami transformation dynamics model,a thermo-mechanical coupled finite element model was established,which considered latent heat,transformation dilatation,TRIP effect,thermal expansion,and so on.By the model,the influence of latent heat,TRIP effect on temperature and residual stress was investigated quantitatively during unsymmetrical controlled cooling of X65 heavy pipeline plate from 860℃ to low temperature with 3mW/mm2K laminar cooling coefficient on top surface and 1mW/mm2K laminar cooling coefficient on bottom surface.The results show that the latent heat enhances about 52.7℃ during phase transformation and the cooling speed of bottom surface and inner slows 50% and 25% respectively because of the increasing of latent heat,and the latent heat increases the temperature of plate 44℃ finally.The magnitude and distribution of residual stress are influenced by shifting the stress peak due to latent heat and TRIP effect.