斜坡长度对M2高速钢坯料显微组织的影响

Influence of Inclined Slope Length on the Microstructure of M2 High Speed Steel Ingots

采用斜坡预结晶法制备了M2高速钢坯料,研究了斜坡长度对坯料显微组织的影响,利用I mage Tool软件对组织进行了定量分析。结果表明,随着斜坡长度的增加,初生奥氏体不断地向球形或近球形转变,且网状碳化物均匀、细小。当斜坡长度大于一定值后,坯料的显微组织恶化,出现少量树枝晶组织。当斜坡长度为500 mm时,坯料的显微组织最好,初生奥氏体的平均等效直径为50.8μm,形状因子为0.83,碳化物的平均厚度为5.21μm。

M2 high speed steel ingots were prepared by inclined slope pre-crystallization method. The effect of inclined slope length on the microstructure of M2 HSS ingots was investigated, and the microstructure was quantitatively assessed by Image tool software. It is found that with increaseof slope length, the primary austenite is changed into globular and near-spherical crystals gradually, and the t network carbides become uniform and fine. If the slope length is greater than a fixed value, the microstructure of ingots is deteriorated, a few dendrite crystals appeare. When the slope length is 500 mm, the optimum microstructure of ingotscan be obtained, and its mean equivalent diameter of primary austenite crystal grain, shape factor and mean thickness of network carbides are 50.8 μm, 0.83 and 5.21 μm respectively.