Microstructure Characteristics and Mechanical Properties of X80 Pipeline Steels

• 作 者: 周民
• 机 构: State Key Lab of Rolling Technology and Automation,Northeastern University,
• 出 处: Journal of Wuhan University of Technology(Materials Science
• 发表日期: 2012年02期
• 关键词: polygonal ferrite pipeline Pipeline steels granular reaches martensite elongatio

The relation between microstructure characteristics and mechanical properties of X80 pipeline steels was investigated using optical microscopy,scanning electron microscopy,etc.It is shown that the structure consists of polygonal ferrite(PF),quasi-polygonal ferrite(QPF),acicular ferrite(AF),and granular bainitic ferrite(GF).With increasing volume fraction of M-A islands(below 3%),the yield strength increases.With increasing content of higher angle grain boundaries(HAGBs),the yield strength,elongation,and DWTT properties at-15 ℃ increase,and the volume fraction of M-A islands reaches its highest point in the steel containing the most volume fraction of GF.

The relation between microstructure characteristics and mechanical properties of X80 pipeline steels was investigated using optical microscopy, scanning electron microscopy, etc. It is shown in the structure consists of polygonal ferrite (PF), quasi-polygonal ferrite (QPF), acicular ferrite , and granular bainitic ferrite (GF) .With increasing volume fraction of MA islands (below 3%), the yield strength increases.With increasing content of higher angle grain boundaries (HAGBs), the yield strength, elongation, and DWTT properties at -15 ° C increase, and the volume fraction of MA islands reaching its highest point in the steel containing the most volume fraction of GF.