| 摘要 |
PURPOSE:To make a step difference as less as possible even in the case of partially arranging hardened layer and to prevent the development of crack in the hardened layer by heating after sticking the specific Fe-W alloy powder sheet on surface of a C contained ferrous material and forming the hardened layer of Fe-W-C ternary system eutectic. CONSTITUTION:On the surface of the ferrous material containing >=3wt.% C, powder alloy composing of 10-25% W and 2% inevitable components and the balanced iron, is mixed with resin binder and stuck as the alloy powder sheet having 0.2-1.5mm thickness. Next, this is heated at 1,090-1,200 deg.C to diffuse C in the above ferrous material into the above sheet side and the Fe-Mo- C ternary system eutectic is crystallized, to form the hardened layer having <=5% shrinkage percentage, >=40% surface area ratio of carbide and >=10% porosity. By this method, at the time of crystallizing the liquid phase by restraining the shrinkage percentage to low, the crack is not developed on the hardened layer and even in the case of partially forming the hardened layer, the step difference can be made as less as possible.
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