爆発硬化した高マンガンオーステナイト鋳鋼の諸特性

抄録

For the improvement of wear-resistance of high manganese austenitic cast steel, explosion hardening treatment has been tried recently. In this study, in order to clarify the characteristics of explosion hardened Hadfield's manganese cast steel, the hardness distribution, grain size, microstructure, phase transformation, crack and residual stress in the explosion hardened layer were examined.
The results obtained are as follows:
(1) Explosion impact produced a deep hardened layer and high hardness.
(2) Explosion treatment did not give much effect on grain size.
(3) The strain markings in Hadfield's manganese steel were classified into five groups, namely simple, Widmannstäten-like, wide, distorted and complex ones. In explosion hardened steel, a good many Widmannstäten-like markings were observed.
(4) γ→ε transformation occurred in the thin layer of explosion impact surface and deformation twins were observed in the explosion hardened layer.
(5) Microcracks were observed in the surface layer of specimens given two and three explosion impacts but none was found in the specimens given one explosion impact. It was difficult to detect them by liquid-penetrant inspection.
(6) High tensile residual stress generated in the surface hardened by explosion.