奥氏体化保温时间对高速钢工作辊组织和耐磨性的影响

Effect of Austenizing Time on the Microstructure and Wear Resistance of the HSS Work-Roll

制备了高碳高钒系高速钢辊环,通过SEM、EDS、XRD分析以及硬度测量研究了奥氏体化保温时间对高碳高钒系高速钢轧辊材料的组织和耐磨性的影响。结果表明,随着奥氏体化保温时间的增加,在铸造过程中形成的M3C型碳化物逐渐溶解或向M2C型碳化物转变;MC型碳化物在晶内逐渐析出,且随着奥氏体化保温时间的延长逐渐圆整为粒状或棒状。在奥氏体化保温过程中,M2C型碳化物按如下公式发生分解:M2C+γ-Fe→MC+M6C;未溶的大块M3C型共晶碳化物是高速钢试样耐磨性差的原因,随着奥氏体化保温时间的增加晶内不断析出的MC型碳化物是高速钢试样耐磨性提高的主要因素;长度<100μm、宽度<20μm的条状碳化物在磨损过程中不易脱落。

The effect of austenizing time on the microstructure and wear resistance of the HSS work-roll manufactured by centrifugal casting method were investigated. The SEM, EDS, X-ray diffraction analysis, and hardness measurement were conducted on the material to identify carbides. During the austenization, the bulky M3 C carbide dissolved into austenite or transformed to M2 C carbides, and then the metastable M2 C carbides decomposed as ME C ＋ austenite→M6C ＋ MC;the MC carbides were precipitating in the cells and growing into the granular or rod-like shape. The most important factor affecting wear resistance of HSS material was the volume fraction of MC carbides formed in the cells. The strip-like carbides whose length is less than 100 μm and width less than 20μm represents the high wear resistance.