摘要 |
A manufacturing method for a composite steel part including preparing an intermediate product in which an extra portion, which has a thickness equal to or more than that of a carburized layer to be formed in a subsequent carburizing step, has been added to a welding expected portion, carburizing the intermediate product by heating to an austenitizing temperature or more in a carburizing atmosphere, then cooling the intermediate product at a cooling rate less than a rate at which martensitic transformation occurs and without completing structural transformation due to the cooling, quenching a portion of the intermediate product after heating to an austenitizing range by high-density energy and thereafter cooling to cause martensitic transformation to form a carburized quenched portion, removing an extra portion of the intermediate product; and then welding a second steel part to the welding expected portion.
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