1.Material Research Institute，Dongfang Boiler Group Co.，Ltd.，Zigong 643001，China
2.Laboratory for High Temperature-high Pressure Material and Welding Engineering of China Machinery Industry Federation，Zigong 643001，China
Abstract：In this paper，the large-diameter thick-wall pipe12Cr1MoVG was subjected to multiple simulated post-weld heat treatments to study the effects of multiple heat treatments on the performance uniformity and microstructure stability of steel tubes by means of mechanical properties testing equipments，optical microscope（OM），scanningelectronmi-croscopy（SEM）. The results show that after three times of tempering heat treatment，the strength and hardness are slightly decreased，the impact toughness index is stable，and the stability of metallographic structure is good，that is，as long as the process is properly controlled，the performance uniformity and microstructure stability of the large-diameter thick-wall pipe 12Cr1MoVG after multiple heat treatments are still good；the relationship between intensity and spheroidization level is not completely consistent with the DL/T773 standard.The test compensated for the insufficiency of on-site heat treatment to destroy the sampling，and provided important data support for the evaluation of boiler pipe counter part installation and rework heat treatment.
2019, Vol. 37 
