<研究論文>鋳鋼による超合金粉末の鋳ぐるみとその組織および硬さの評価

概要

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In order to improve wear resistance of cast steel, hard alloy powder layer was inserted bymolten cast steel at 1843K. The vertical cross-section of the inserted layer was examined on themicrostructure and the hardness, The results obtained are as follows. Sound inserted layer of 3mm in thickness was confirmed to be formed without any defects on the surface of cast steel.A reaction layer with some lump shaped particles was formed in the interface between the insertedlayer and the mother metal (cast steel). The lump shaped particles were identified to be Fe3W3Cphase which had a cubic structure with a lattice constant of 11.1094 X1O-8cm. The particles wereconsidered to be formed by a reaction between the Co bond phase dissolving WC in hard alloypowder and the molten iron dissolving low concentration of C in molten steel. The hardness ofcast steel was about Hv300, while the inserted layer exihibited high hardness of Hv600 to 800.Especially, the reaction layer showed peak hardness of Hv1800, but the layer was not brittle. Thetoughness of the reaction layer was considered to be due to a mixed structure of tough bainite andretained austenite around the hard Fe3W3C particles. The present method using the inserted hardalloy powder layer is therefore to be very effective one for local hard facing of cast steel.
秋田大学の論文