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对P92钢进行了TTT图测定,观察分析了过冷奥氏体的等温转变的类型及组织形貌。结果表明,经1050℃奥氏体化,在650~800℃之间进行等温转变,奥氏体中首先析出碳化物(Cr23C6),接着发生F+P转变;在170~400℃区间存在马氏体的变温转变和贝氏体相变。在400~650℃区间存在宽广的海湾区,且贝氏体相变的孕育期比共析分解短得多。同时发现了两种特殊的组织形态:珠光体组织为纤维状,下贝氏体中的碳化物为颗粒状。
The PTA steels were measured by TTT. The type and microstructure of the supercooled austenite were observed and analyzed. The results show that when austenitizing at 1050 ℃ and isothermal transformation at 650 ~ 800 ℃, carbides (Cr23C6) are first precipitated in austenite followed by F + P transformation. At 170 ~ 400 ℃, Body temperature transformation and bainite transformation. In the region of 400 ~ 650 ℃ there is a wide bay area, and the bainite transformation period is much shorter than that of eutectoid decomposition. At the same time, two special forms were found: the pearlite was fibrous and the carbides in the lower bainite were granular.