9%Ni钢斜Y形坡口裂纹试验的数值模拟

Numerical simulation of slit type cracking test for 9%Ni steel

摘要: 利用SYSWELD有限元计算软件,采用双椭球焊接热源模型,对9%Ni钢斜Y形坡口裂纹试验中不同预热温度下的试件进行了焊接温度场和应力场的数值模拟.研究了试件的焊接温度场和应力场的分布规律,分析了预热温度对焊接热过程和焊后残余应力的影响.结果表明,提高预热温度时,一方面焊后冷却速度降低,有利于氢的逸出和马氏体的自回火作用;另一方面,横向残余应力水平增加,试件总体应力水平增加,冷裂纹敏感性增加.因此,焊接9%Ni钢时,不宜采用过高的预热温度.

Abstract: With SYSWELD software, the temperature and stress field of 9% Ni steel Y-slit weldments with different preheat temperatures were simulated by applying double-ellipsoid heat source.Distribution laws of welding temperature and stress field were studied.Effects of preheat temperature on welding heat cycles and residual stress were analyzed.Results show that with increasing preheat temperature, cooling rate decreases facilitates escaping of hydrogen and self-tempering of martensite, the average stress level and cold-cracking susceptibility of the weldments increase, so high preheat temperature shall be avoided for 9%Ni steel welding.