粉末冶金M2高速钢的制备与组织性能研究

Powder metallurgy preparation and microstructure and properties of M2 high speed steel

采用机械球磨法制备了M2高速钢(HSS)粉末,研究了烧结温度对数控机床用高速钢显微组织、硬度、抗弯强度等性能的影响,并分析了热处理对高速钢显微组织和力学性能的影响。结果表明,球磨时间为16 h时高速钢粉末的颗粒分布均匀、平均尺寸最小;在烧结温度为1245℃时,高速钢试样中未见显微孔洞或者裂纹等缺陷存在,同时碳化物细小、弥散;烧结温度为1235℃时,高速钢试样的烧结机制为固相烧结,相对密度为87.2%,升高烧结温度至1245℃及以上时,高速钢试样的烧结机制为液相烧结,相对密度保持在98%以上;随着烧结温度的升高,高速钢试样的磨损失重呈现先减小后增大的趋势,抗弯强度呈现先增加后减小的趋势,在烧结温度为1245℃时具有较小的磨损失重和最大的抗弯强度;淬火和回火热处理可以进一步提高烧结试样的洛氏硬度。

M2 high speed steel powder was prepared by mechanical ball milling,the effect of sintering temperature on microstructure,hardness and bending strength of high speed steel was studied,and the effect of heat treatment on microstructure and mechanical properties of high speed steel was analyzed.The results show that the particle distribution of HSS powder is uniform and the average size of HSS powder is the smallest when the milling time is 16 h,and there are no micro-holes or cracks in the samples;when the sintering temperature is 1245℃,and the carbide is fine and dispersed.The sintering mechanism of HSS sample is solid phase sintering at 1235℃,the relative density is 87.2%,and the sintering mechanism of HSS specimen is liquid phase sintering when the sintering temperature rises to 1245℃or above,and the relative density keeps above 98%.With the increase of sintering temperature,the wear weight loss of HSS specimen decreases first and then increases,and the bending strength increases first and then decreases.The hardness of the sintered samples can be further improved by quenching and tempering treatment.