Thermo-Mechanical Simulation of Reheat Cracking in Welding CGHAZ of Vanadium-modified 2.25Cr1Mo Steel
The reheat cracking, also known as stress relief cracking, has occurred many times in the welding coarse grained heat affected zones (CGHAZ) of Vanadium-modified (V-mod) 2.25Cr1Mo steel, but seldom researches on this problem have been conducted until now.In this paper, reheat cracking in welding CGHAZ of V-mod 2.25Cr1Mo steel was studied by the thermo-mechanical simulation methods.A screening test was carried out for simulating similar material to the real CGHAZ.The high temperature ductility of simulated CGHAZ was measured in the range of 600~705 ℃ for determining the most sensitive temperature to reheat cracking.And then, the reheat cracking phenomena at the sensitive temperature was reproduced by Isothermal stress relaxation test and the micro-morphology of cracks was observed and analyzed.The results show that the thermal simulation parameters for acquiring the most similar materials to real CGHAZ are heat input of 35kJ/cm, heating rate of 1000℃/s and holding time at 1320℃ of 1s.The reduction of area (RoA) of the simulated CGHAZ specimen first decreases and then increases with increasing temperature.It exhibits a minimum value at 675℃, corresponding to the most sensitive temperature to reheat cracking.In the stress relaxation test, the sample failure typically occurs with very low stress relaxation proportion (less than 15%) and extremely poor ductility (less than 5% in RoA).Both microvoid coalescence along the PAGB and intergranular wedge type cracks were observed in the fractured sample, proposing a mixed cracking mode of W-type and R-type in stress relaxation.
Reheat cracking Vanadium-modified 2.25Cr1Mo Thermo-mechanical simulation
Yichun Han Xuedong Chen Zhichao Fan Huaquan Bu
National Engineering Technical Research Center on PVP Safety,Hefei General Machinery Research Instit National Engineering Technical Research Center on PVP Safety,Hefei General Machinery Research Instit
国际会议
2014 International Symposium on Structural Integrity,ISSI2014(2014国际结构完整性学术会议)
兰州
英文
225-232
2014-08-20（万方平台首次上网日期，不代表论文的发表时间）