Abstract: Based on the need of high wear resistance， a new kind of high-vanadium high-speed steel named W3Mo4Cr5V6 was designed. The transformation behavior of metastable M₂C carbides in the high temperature heating process of the steel was analyzed by means of SEM and EMPA. The results show that the cophortic M2C carbide will undergo M₂C+γ-Fe→M₆C+MC+M₇C₃ transition at high temperature heating process.A large number of W， Mo-rich M₆C and a small amount of V-rich MC and Cr-rich M₇C₃ are formed around the Mo and W-rich M₂C phase. With the increase of temperature from 950 ℃ to 1 150 ℃， the high temperature transformation of M₂C carbides gradually tends to be complete and the fibrous M₂C is easier to decompose and transform than lamellar M₂C， and the lamellar or fibrous morphology distributed in the austenite grain boundary with discontinuous network is transformed into the granular morphology distributed at the grain boundary， which can effectively reduce the harm of network carbides to the grain boundary. The research can provide an effective reference for the composition and morphology control of carbides distributed at the grain boundaries of high-speed steel and the optimal selection of parameters such as temperature and time of hot processing and heat treatment process.

Key words: High-speed Steel, Electroslag Remelting, M₂C Carbide, High Temperature Transition, Component Analysis

摘要： 基于高耐磨性的需要，设计了一种W3Mo4Cr5V6高钒高速钢，利用SEM、EMPA等手段对该钢高温加热过程亚稳态M₂C碳化物的分解转变行为进行了分析。结果表明，共晶碳化物M₂C在高温加热过程会发生M₂C+γ-Fe→M₆C+MC+M₇C₃的转变，在富Mo、W的M₂C相周围形成了大量富W、Mo的M₆C及少量富V的MC和富Cr的M₇C₃。随着温度由950 ℃增至1 150 ℃，M₂C高温转变逐渐趋于完全，且纤维状M₂C比层片状M₂C更易分解转变，最终，由呈断续网状分布于奥氏体晶界的层片或纤维状形貌向零星分布于晶界的颗粒状形貌过渡，可有效减少网状碳化物对晶界的危害。研究可为高速钢中晶界碳化物成分、形态控制及其热加工、热处理过程温度与时间等参数选择提供有效参考。

关键词: 高速钢, 电渣重熔, M₂C碳化物, 高温转变, 成分分析