Grain Refinement Behavior of Pipeline Steel in Welding Heat Affected Zone
Self refining grain behavior of X80 pipeline steel in the heat affected zone was studied systematically by physical simulation method. The sizes and distribution of the inclusions which promote intra-granular ferrite nucleation were measured using the automatic image analyzer, and the figures of the intra-granular ferrite which has self refining grain behavior were observed using transmission electron microscopes with energy dispersive X-ray spectroscopy, the fracture toughness values of the coarse grain zone in the HAZ were also measured. The results show that the welding thermal cycle has nearly no effect on the sizes and distribution of the inclusions in the HAZ. The reasons of self-refining grain in the HAZ are that the small non-metallic inclusions such as MnO、TiO、MnS、CuS and (Mn，Cu)S in X80 pipeline steel,which can induce the nucleation of intra-granular ferrite in the welding process, and sympathetic nucleation of intra-granular ferrite makes the coarse grains refined in the HAZ. First intra-granular ferrite has large boundary energy and high density dislocation, which induce the sympathetic nucleation of intra-granular ferrite.
grain refinement intra-granular ferrite HAZ X80 pipeline steel
S F Yu Y Lei Z Y Li
College of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 4 College of Mechanical and Electronic, China University of Petroleum, Dongying 25701, Shandong, China
国际会议
郑州
英文
2007-10-23（万方平台首次上网日期，不代表论文的发表时间）