| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing steel parts in which quenching and tempering to the necessary portion of the quenching can be applied by heating only one time, resulting in high contribution to reduction of cost-bearing needed for the heat treatment and the improvement of a production efficiency. SOLUTION: In this manufacturing method, after hot-forging a connecting rod as one of the steel part, while the heat higher than Al transformation point remains, a masking is applied to a large end part 1 and a small end part 2, and only column part 3 is rapidly cooled (water-cooling) to perform the quenching and thereafter, the whole body of connecting rod is left in the air. In this leaving in the air, the heats of the large end part 1 and the small end part 2 are conducted to the column part 3 and the column part 3 is heated to become in a tempering-state to obtain the desired hardness in this part. COPYRIGHT: (C)2007,JPO&INPIT
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