Investigation of M2 High Speed Steel Produced by Osprey Process

Abstract

Microstructural and property assessments have been undertaken on spray deposited M2 high speed steel in the as deposited condition and after hot forging. The response of the material to hardening treatment has also been studied. The microstructure of the as deposited material showed a small grain size with a cellular carbide network. Subsequent hot forging produced a uniform dispersion of fine (0·5–2 μm) carbides. Austenitising the as deposited sample at 1200°C resulted in spheroidisation of the continuous grain boundary M₆C carbide film. EDX analysis showed the resultant spheroidised particles to be predominantly vanadium rich MC. No significant differences were observed between the hardening response of M2 high speed steel produced conventionally and by spray deposition. The bend strength values of spray deposited M2 were isotropic and similar to those observed for powder metallurgy samples. PM/0487