| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a rough-formed bearing with which a spheroidized annealing after roughly forming into a prescribed shape with a hot-forging, can be omitted and the decarburization on the surface layer part of the rough-formed material can be restrained. SOLUTION: A high carbon-chromium bearing steel material having a chemical composition composed by mass% of 0.7-1.2% C and 0.8-1.8% Cr and a micro-structure of mixed structure of primary precipitated cementite and pearlite, having≤10 aspect ratio and≤1.5μm short diameter, is heated to the temperature T°C in the temperature zone of Ae<SB>1</SB>point to (Aem point-30°C) at≥10°C/s heating speed in the temperature zone of≥600°C, and successively, after reaching to this temperature T°C, the processing is started within 30min (30min inclusive) and in the temperature range of Ar<SB>1</SB>point to (Aem point-80°C), forging processing is performed at the deformed quantity of≥15% the total processing quantity, and after forming to the prescribed rough-formed material shape, this material is cooled at≤5°C/s cooling speed in the temperature range till 400°C. COPYRIGHT: (C)2009,JPO&INPIT
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