9CrMoWV耐热钢的高温持久蠕变性能及组织行为研究分析

为了表征9CrMoWV耐热钢在实际应用中的力学行为,对9CrMoWV钢在不同温度和应力条件下进行持久试验,并对持久试样进行OM、SEM、TEM观察,分析不同温度、应力和持久试验时间对9CrMoWV钢显微组织和宏观、微观断口的影响,同时统计Laves相的尺寸变化及其他第二相分布情况。结果表明,随着试验时间和温度的增加,断口韧窝尺寸增大,板条状马氏体回复程度增大,Laves相的尺寸变化明显,分布于晶界的M₂₃C₆与Laves相均发生不同程度聚集粗化,这是高温低应力区试样断裂的原因之一。

Study on creep rupture properties and microstructure behavior of 9CrMoWV heat-resistant steel at high temperature

In order to characterize the mechanical behaviour of 9CrMoWV heat-resistant steel during practical use, the stress rupture test was carried out under different temperatures and stress conditions. The stress rupture specimens were observed by OM, SEM and TEM. The effects of different temperatures, stresses and durations on the microstructure, macro and micro fracture of 9CrMoWV heat-resistant steel were analyzed. At the same time, the size change of Laves phase and the distribution of other second phase were counted and analyzed. The results showed that with the increase of test time and temperature, the dimple size of fracture surface increased, the recovery degree of lath martensite increased, and the size of Laves phase changed obviously. M₂₃C₆ and Laves phase distributed in the grain boundary were coarsened in varying degrees, which was one of the reasons for the fracture of samples in high temperature and low stress zone.