不同烧结气氛下M3∶2粉末高速钢的性能研究

Properties ofthe PM M3∶ 2 high speed steel in different sintering atmospheres

以水雾化M3∶2高速钢粉末为原材料,分别在真空和真空+氮气两种气氛烧结制备M3∶2粉末高速钢材料。通过X-射线衍射仪(XRD)、扫描电镜(SEM)及力学性能评估等手段研究了材料的物相组成、显微组织、硬度以及抗弯强度。研究结果表明:真空烧结高速钢中主要存在M6C和MC两类碳化物相;真空+氮气气氛烧结的高速钢中除了M6C碳化物以外还含有M(C,N)碳氮化物。两种烧结气氛均能实现M3∶2粉末高速钢的高致密化,而真空+氮气气氛烧结具有更优异的综合性能,其烧结态高速钢的硬度为56 HRC,抗弯强度达3 540 MPa(达到第二代粉末冶金高速钢的性能)。与真空烧结相比,真空+氮气气氛烧结高速钢的硬度和抗弯强度分别提高7.1%以上和18.6%以上。

Vacuum and vacuum plus nitrogen atmosphere were used as the sintering atmospheres for the PM M3 ∶ 2HSS with the M3 ∶ 2 powder as the raw material powder. Phase composition,microstructure,hardness and bending strength of the PM M3 ∶ 2 HSS were investigated by means of XRD,SEM and mechanical performance assessment.The experiment results show that the main carbides of the HSS prepared in vacuum are M6 C and MC; the main carbides of the HSS prepared in vacuum plus nitrogen atmosphere are M6 C and M（ C,N）. The PM M3： 2 HSS can achieve high densification in two kinds of sintering atmospheres. With respect to the vacuum sintering,more excellent performance was achieved in vacuum plus nitrogen atmosphere with hardness of 56 HRC,increased by 7. 1% and bending strength of 3540 MPa,increased by 18. 6%,which reached the performance of the second-generation PM HSS.