9Ni钢薄板的奥氏体化温度及强韧化因素分析

Austenitizing Temperature for 9Ni Steel Thin Plate and Analysis of Strengthening and Toughening Factors

研究了奥氏体化温度对9Ni钢薄板组织性能的影响,并分析了薄板与厚板低温韧性差异的原因。奥氏体化温度高于800℃后,随着奥氏体化温度升高,奥氏体化温度对逆转奥氏体(γ′)的体积分数没有影响;奥氏体化后奥氏体晶粒尺寸减小,晶粒趋于等轴;组织均匀化程度提高;最终组织中取向差大于1 5°区域尺寸减小,低温韧性增加;板条或亚板条束的平均尺寸增加,强度降低。薄板中较小的平均取向差是其低温韧性较低的主要原因。

Influence of austentizing temperature on microstructure and properties of 9Ni steel thin plate was investigated and the causes for inferior cryogenic toughness compared to heavy plate was analyzed.As the austenitizing temperature increased from 800 to 900℃,the volume fraction of reversed austensite was unchanged.The austensite grain size decreased and tended to be equiaxed.The uniformity of microstructure was improved.The cryogenic toughness increased as the zone size decreased which surrounded by higher than 15°misorientation grain boundary.The yield strength decreased as sub-block or lath mean size increased.The lower cryogenic toughness of thin plate was mainly attributed to the less average misorientation.