高速钢M2中共晶碳化物M₂C的性质和形态

来源期刊：钢铁2009年第9期

论文作者：周雪峰 方峰 蒋建清 李德辉 朱旺龙

文章页码：76 - 80

关键词：高速钢； 冷却速度； 共晶M₂C； 形态； 性质

Key words：high speed steel； cooling rate； M₂C eutectic carbide； morphology； property

摘    要：采用砂型和金属型铸造制备M2高速钢铸锭,研究了共晶碳化物M₂C性质和形态随冷却速度的变化规律。结果表明,冷速加快,促进共晶M₂C由平直片层状变为弯曲棒状,并使碳化物中合金元素含量降低,基体合金含量升高。不同形态M₂C热分解性质差异较为明显:片层状M₂C分解产生的MC多分布在碳化物内部,形成大量M₆C+MC复合碳化物;棒状M₂C起始分解温度低于片层状M₂C,MC多形成于碳化物和基体界面处,高温加热时易与M₆C分离,使复合碳化物数量减少。共晶M2C热分解性质的差异与冷速不同引起的合金元素分布变化有关。

Abstract: The effect of cooling rate on property and morphology of M₂C eutectic carbide in M2 high speed steel was investigated by analysis of cast ingots prepared by sand mould and metal mould.The corresponding mechanism was also explored.The results show that the morphology of M₂C carbides transforms from lamellar to rod-like with the increase of cooling rate.Meanwhile,the concentration of alloying elements in M₂C decreases while it increases in the matrix.The decomposition process of lamellar and rod-like M₂C is significantly different.After decomposition,MC forms inside lamellar M₂C while it exists at the interface of rod-like M₂C/γ.The DTA curve indicates that rod-like M₂C is more unstable and decomposes at lower temperature than lamellar M₂C.The property of M₂C depends on the distribution of alloying elements,which varies greatly at different cooling rates.