| 摘要 |
PROBLEM TO BE SOLVED: To provide a forging method for changing the metal structure into the fine ferrite and pearlite structure without employing a conventional quench- and-temper method, obtaining the strength in which the yield point (YP value) exceeds that by the conventional quench-and-temper method, reducing the tensile strength(TS) lower than that by the conventional quench-and-temper method, and improving the workability in the machining. SOLUTION: A forging stock manufactured by adding at least one kind of the fifth group metals such as vanadium, niobium and tantalum to non- tempered carbon steel for machine structural use is heated to the temperature (1,150-1,250 deg.C) suitable to the hot forging, forged to the predetermined shape, kept at the temperature in the temper temperature range in a furnace for the predetermined time, and further naturally cooled to normal temperature.
|
