| 摘要 |
PURPOSE:To make the hardness and structure uniform and to improve the machinability and mechanical strength by cooling a hot forged rough body under specified conditions, working it to a prescribed shape, and carrying out secondary heat treatment. CONSTITUTION:A hot forged rough body is allowed to cool from the solubilization temp. to a temp. just above the austenite transformation point (A1 trans- formation point) at which transformation starts, and is slowly cooled until the transformation finishes after it starts to form a uniform two-phase structure consisting of ferrite and pearlite. The slowly cooled rough body is allowed to cool again to ordinary temp. The rough body is mechanically worked to a prescribed shape, and it is subjected to secondary heat treatment such as carburization and hardening, carbonitriding and hardening, or induction hardening to obtain a finished article. |
