MA形成过程和分布对高强度管线钢力学性能的影响

Effects of Distribution and the Formation Process of MA on Deformation and Toughness of High Strength Linepipe Steel

为了使抗大变形管线钢具有良好的力学性能,了解MA形成过程对管线钢力学性能的影响,研究了在线热处理和离线热处理工艺下试样MA的显微组织结构和力学性能。研究结果表明,马氏体是MA的主要组成部分,MA的分布和形状在两种热处理工艺下都不同,试样MA中出现碳富集,在线热处理试样MA中的碳浓度高于离线热处理试样,不同形态的MA和基体使材料在裂纹扩展中表现出不同的韧性,在线热处理试样其形成的MA结构具有良好的力学性能。

In order to obtain good mechanical properties for pipeline steel with high deformability, for understanding the formation process and its effect on mechanical properties, microstructural analysis of the MA formed through two different heat treatments（on-line heat process and off-line heat process） is conducted. Based on SEM and TEM observation, it is found that the MA consisted mainly of martensite and its distributions and shapes are different between on-line and off-line heat process samples. Carbon concentration occurs in MA of sample, the carbon concentration of on-line heat treatment sample is higher than that of off-line heat treatment, the MA with different shape and substrate material show different toughness in the crack propagation, MA structure formed by on-line heat treatment is with good mechanical properties.