Research and Prospect on Relationship Between Microstructure Characteristics and Strength-Toughness of High Grade Pipeline Steel

The strength property of high grade pipeline steel has been obviously improved with the rapid development of the constructing of oil and gas pipelines. And the excellent strength-toughness matching of pipeline steel is very important. The major affecting factor on strength-toughness of pipeline steel is microstructure characteristic. In this paper, the research status of pipeline steel microstructure characteristic including effective grain size, non-metallic inclusions and banded structure is summarized at home and abroad. In addition, the shortcomings of former research on the relationship between microstructure characteristics and strength-toughness are also analyzed for this pipeline steel. On this basis, a solution is put forward to investigate the characterization of effective grain size and micro-mechanical behavior of inclusions and banded structure with the method of electron backscatter diffraction and the method of SEM in situ observation. And the necessities and feasibilities of the solution are discussed.