Abstract: The impacted and tensile-fractured specimen of 316H steel medium plate was analysised by SEM, the result was showed that the morphology of fractured specimen with lower impact energy and yield strength of 316H medium plate was brittle fracture because of σ precipitation phase in the middle of plate, which decreased the plasticity and toughness of steel. The formed link of a phase was found out in process of rolling and heat treatment, and then the cooling rate after rolling, heating rate, holding temperature, holding time in process of heat treatment were adjusted, the ct phase was not precipitated in any position in the plate, the mechanical property of plate in every place of 316H medium plate is qualified.

摘要： 采用扫描电镜对316H钢中厚板冲击、拉伸试样断口进行观察,结果表明,冲击不合和屈服强度较低试样断口形貌均为脆性断裂,因断口上有大量富铬钼的σ相,严重影响了钢的塑性、韧性。分析了钢板在轧制及热处理过程中可能出现σ相的环节,对钢板热轧后的冷却速率,钢板固溶过程中的加热速度、保温温度、保温时间进行了一系列调整,调整工艺后生产的316H不锈钢中板厚度方向不再析出σ相,各个位置力学性能满足要求。

关键词: 316H不锈钢, 热处理工艺, 力学性能, 析出相