1. New Product Development and Application Center, Nanjing Iron and Steel Co., Ltd., Nanjing 210035, Jiangsu, China 2. State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, Hebei, China
Abstract��For revealing the effect of t8/5 on microstructure and hardness of X90 pipeline steel in welding heat affected zone (HAZ) , the thermal cycles process at different t8/5 (10��300 s) were simulated by a Gleeble-3500 simulator. The SHCCT curve was established through analysis of thermal expansion curve and microstructure. For each sample, the microstructure was observed by optical microscopy (OM) and transmission electron microscope (TEM), and the vickers hardness was measured. The results show that with the t8/5 decreasing, the starting and finishing temperatures for phase transition in HAZ of experimental steel decreased. The dominated microstructure changed gradually from the granular bainite (GB) to the lath bainite (LB). The prior austenite grain and bainitic ferrite were obviously refined. The variation in the microstructure of HAZ caused an increasing hardness value. The t8/5 of 10��20 s is recommended for the girth welding of this steel.
��껣���־�����ǣ�������ڣ������. X90���߸�SHCCT���ߵIJⶨ�����[J]. �й������ڿ���, 2014, 32(2): 10-14.
TIAN Hao,FU Zhi-bin,JIANG Jin-xing,LI Jun,FAN Lei,WANG Qing-feng. Measurement and Analysis of SHCCT Curve for X90 Pipeline Steel. Chinese Journal of Iron and Steel, 2014, 32(2): 10-14.
2014, Vol. 32 
