Microstructure and toughness of coarse grain heat-affected zone for Nb-microalloyed X80 pipeline steel  

作　　者：李亚娟 李午申 陈仁华 

机构地区：[1]School of Material Science and Engineering, Tianjin University, Tianjin, 300072 [2]College of Science, Civil Aviation University of China, Tianjin, 300300

出　　处：《China Welding》2011年第4期57-61,共5页中国焊接（英文版）

摘　　要：Based on welding thermal simulation on Nb-microaUoyed XSO pipeline stee! using Gleeble-3500 thermal simulation equipment, microstlttcture and impact toughness in coarse grain heat-affected zone （CGHAZ） under different welding parameters were investigated in this paper. The results show that high heat inputs with low preheats or low heat inputs with high preheats should be applied to achieve high impact toughness. Coarse original austenite grains may lower impact toughness. CGHAZ microstructure is mostly composed of upper bainite, granular bainite and lath bainite. The phase composition of microstructure and the quantity, size, shape of M/A constituents both have effects on impact toughness.Based on welding thermal simulation on Nb-microaUoyed XSO pipeline stee! using Gleeble-3500 thermal simulation equipment, microstlttcture and impact toughness in coarse grain heat-affected zone （CGHAZ） under different welding parameters were investigated in this paper. The results show that high heat inputs with low preheats or low heat inputs with high preheats should be applied to achieve high impact toughness. Coarse original austenite grains may lower impact toughness. CGHAZ microstructure is mostly composed of upper bainite, granular bainite and lath bainite. The phase composition of microstructure and the quantity, size, shape of M/A constituents both have effects on impact toughness.

关 键 词：Nb-microalloyed XSO pipeline steel heat-affected zone MICROSTRUCTURE TOUGHNESS 

分 类 号：TG457.11[金属学及工艺—焊接] TG142.41[一般工业技术—材料科学与工程]