PURPOSE: To junction a steel member to a sintered hard alloy with high strength, by making the sintered hard alloy and the steel member tightly adhere to each other directly, and melting a press-contact surface of the steel material side in the shape of a slit having specific width, by irradiating a high energy beam in a non-oxidizing atmosphere.
CONSTITUTION: To the inside of a sintered hard alloy ring 5, a steel material ring 6 is fitted and made to tightly adhere by means of cold-fitting, an electronic beam 3 is irradiated to the end part of a press-contact surface A so as to hit at least within 0.5mm against the steel material side, in a non-oxidizing atmosphere or a vacuum, a molten layer 7 is formed on the press-contact surface of the steel material side, and the sintered hard alloy ring 5 and the steel material ring 6 are junctioned. As a result, no crack is generated in the center part of the press- contact surface A, and fatigue strength is raised as a whole. Also, the junction surface A of the steel member is of a soft quality, and as for the quantity of carbon, 0.5wt% is desirable, and as for the part except the junction surface A, it is preferable to increase the abrasion resistance by raising its hardness by means of carburization and quenching.
HAGIWARA KOUTAROU
WAMOTO SHIYOUZOU
HIRAYAMA JIYUICHI
HARA AKIO
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