摘要
基于MSC.Marc软件平台,开发了考虑蠕变效应的热-弹-塑性有限元计算方法。采用该方法模拟了Q345平板接头TIG重熔焊接过程和焊后热处理过程中的应力场,并重点研究了焊后热处理过程中蠕变效应对焊接残余应力的影响,基于数值模拟结果研究了焊后热处理消除残余应力的机理。同时,采用盲孔法实测了焊接及热处理后平板接头的残余应力,并与数值模拟结果进行了对比。此外,还探讨了2种不同的蠕变模型对焊后热处理残余应力计算精度的影响,针对Q345低合金高强钢,提出了一种简易高效、适合于工程应用的蠕变模型。结果表明:数值模拟得到的残余应力与实验值吻合良好,验证了所开发的集成计算方法的有效性。热处理计算过程有必要考虑材料的蠕变效应,否则会严重高估热处理后的残余应力。采用本工作提出的简易蠕变模型,在较少损失计算精度的前提下可使计算效率提高10倍左右。
Low alloy high strength steel,owing to its good mechanical properties and low cost,is widely used in bridge,building,pressure vessel and other engineering structures.Steel structures will inevitably produce residual stress and deformation after welding with the characteristics of concentrated heat source and local heating.Heat treatment is recognized as an effective method to eliminate the residual stress after welding.However,there is no quantitative and systematic study on the mechanism of heat treatment to eliminate residual stress when numerical simulation method is used to study post weld heat treatment(PWHT).Meanwhile,creep is an important factor in the process of PWHT on low alloy high strength steel.It is necessary to study the influence of creep on residual stress prediction so as to develop a simplified creep model used in practice more efficiently.Based on MSC.Marc software platform,a thermal-elastic-plastic finite element method(T-E-P FEM)considering creep effect is developed.The stress field during welding and PWHT of Q345 remelting joint was simulated by the integrated calcu-lation method.The effect of creep on welding residual stress during PWHT was emphatically studied.Based on the results of numerical simulation,the mechanism of eliminating residual stress by PWHT was explored.At the same time,the residual stresses of welded and heat treated joints were measured by blind-hole method,and the results were compared with those of numerical simulation.In addition,the effect of two different creep models on the calculation accuracy of residual stress in PWHT is also discussed.A simple and efficient creep model suitable for engineering application is proposed for Q345 low alloy high strength steel.The results show that the residual stresses obtained by numerical simulation agree well with the experimental values,which verifies the validity of the integrated calculation method developed.It is necessary to consider creep effect in the process of PWHT,otherwise the residual stress after heat treatment will
作者
逯世杰
王虎
戴培元
邓德安
LU Shijie;WANG Hu;DAI Peiyuan;DENG Dean(College of Materials Science and Engineering,Chongqing University,Chongqing 400044,China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2019年第12期1581-1592,共12页
Acta Metallurgica Sinica
基金
国家自然科学基金项目No.51875063~~
关键词
残余应力
焊后热处理
蠕变
数值模拟
residual stress
post weld heat treatment(PWHT)
creep
numerical simulation
