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利用金相(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)及能损谱(EELS)等手段,研究了含稀土轧辊用高速钢在1100℃淬火和550℃两次回火热处理过程的微观组织变化特征,重点探讨了碳化物行为。结果表明,淬火加热过程中热稳定性较高的MC和M6C型一次共晶碳化物难以溶解,亚稳态的M2C型一次共晶碳化物则发生分解反应得到MC和M6C两种碳化物,分解形成的M6C较MC量多且尺寸较大,小颗粒MC包含在M6C之中;淬火基体组织由马氏体和残留奥氏体组成,淬火马氏体既有板条马氏体也有孪晶型马氏体。经两次回火后,残留奥氏体得以有效消除,大量细小富V的MC型二次碳化物弥散析出产生二次硬化现象。
The effects of quenching of high speed steel with rare earth roll at 1100 ℃ and annealing at 550 ℃ were studied by OM, SEM, TEM, XRD and EELS. Two tempering heat treatment process microstructure changes, focusing on the behavior of carbides. The results show that the first-phase eutectic carbides of MC and M6C with high thermal stability during quenching are hard to dissolve, while the metastable M2C first eutectic carbides undergo decomposition reaction to obtain two kinds of carbides, MC and M6C, which decompose M6C formed more than the amount of MC and larger size, small particles contained in the M6C MC; quenched matrix microstructure composed of martensite and retained austenite, both quenching martensite lath martensitic twin mode Martensite. After twice tempering, the retained austenite can be effectively eliminated, a large number of small and rich V MC secondary carbide precipitated secondary hardening phenomenon.