Age-hardening of surface age high speed steel on high carbon steel after plasma decarbonizing

Steel T8 treated by plasma surface decarburizing is alloyed by the Xu-Tec process with Co, W and Mo. An alloying layer of Fe-Co-W-Mo with low carbon content is formed on the surface of the high carbon steel, which is an advanced gradient composite. The specimens after alloying are treated by the solution and aging treatments. The characteristics of age-hardening of the alloying layer are studied. The surface alloying layer of Fe-Co-W-Mo possesses a very strong ability of age-hardening. The hardness of the surface layer is increased from 200 to 1070 Hv after the solution treatment at 1190 degreesC and aging 30 min at 400 degreesC. The experimental results show that the surface aged high speed steel possesses not only high surface hardness, but also enough strength of the bulk material, so it will be used widely in the fields of tool, mould and others where high wear-resistance is required. (C) 2000 Elsevier Science B.V. All rights reserved.