Research on Acicular Ferrite Nucleation Induced by Inclusions in Pipeline Steel Welding Heat Affected Zone

Abstract

In this paper, the HAZ of pipeline steel in high heat input welding is researched, including the microstructure and properties of HAZ, the embrittlement of HAZ and the existing problems and solutions of HAZ. The results show that the welding normalized zone is the best part of the HAZ. The main embrittlement mode of HAZ in the pipeline steel is the coarse grained embrittlement and the microstructure embrittlement. The theoretical research system of adding nano-oxide induced the intra-granular acicular ferrit nucleation in HAZ will be a new research direction of solving the appearing problems of pipeline steel in high heat input welding. Introduction