凝固速率对M2高速工具钢铸态组织的影响

发布时间：2018-05-18 00:09

本文选题：高速工具钢 + 凝固速率　；参考：《材料热处理学报》2017年01期

【摘要】：采用OM、SEM等手段分析了采用水冷铜模和铸铁模铸造获得的不同冷速M2高速钢的铸锭,研究了冷却速度对其铸态组织的影响。结果表明,随着冷却速度的增加,铸态组织明显细化,原始结晶的奥氏体晶粒尺寸明显减小,晶粒均匀性明显增加;莱氏体网的均匀性增加,莱氏体共晶碳化物的厚度变薄,莱氏体团尺寸减小;M_2C共晶碳化物由片层状转变为尺寸较小的棒状,棒状碳化物的界面没有片状平直光滑,更易形成缩颈或断开,棒状碳化物的长度和厚度更小;与片状共晶碳化物相比,棒状M_2C共晶碳化物在高温加热时更容易发生分解和分断球化,其主要原因是具有弯曲表面和较多缩颈的M_2C碳化物具有更大的热力学和动力学驱动力。
[Abstract]:The ingots of M2 high speed steel with different cooling rates obtained by water cooled copper die casting and cast iron die casting were analyzed by means of OMW-SEM and the effect of cooling rate on the as-cast microstructure was studied. The results show that with the increase of cooling rate, the as-cast microstructure is obviously refined, the austenite grain size of the original crystal decreases obviously, and the grain uniformity increases obviously, and the thickness of the eutectic carbides becomes thinner with the increase of the homogeneity of the Lleite body network. The size of Leydite group is reduced and the size of M2C eutectic carbides is reduced from lamellar layer to rod-shaped carbide with smaller size. The interface of rod-like carbides is not flat and smooth, and it is easier to form neck-shrinking or disconnected carbides, and the length and thickness of rod-like carbides are smaller. Compared with the flake eutectic carbides, the rod-like M2C eutectic carbides are easier to decompose and break spheroidized at high temperature. The main reason is that the M2C carbides with curved surfaces and more necking have more thermodynamic and kinetic driving forces.
【作者单位】：东南大学材料科学与工程学院;钢铁研究总院特殊钢研究所;江苏省(天工)工模具钢工程技术研究中心;
【基金】：江苏省科技成果转化项目(BA2010139)
【分类号】：TG142.45;TG260

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