| 摘要 |
PURPOSE: A forging method is provided to improve workability in machining, by turning the metallographical structure of products subject to impact load to a fine ferrite-pearlite structure, without adopting quenching and tempering, to obtain as strength a yield point exceeding that by quenching and tempering, and making the tensile strength smaller than that obtained by quenching and tempering. CONSTITUTION: The forging method is characterized in that a forged material manufactured by adding at least one kind of group 5 metals is heated to a temperature suitable for hot forging, and after forging to a prescribed shape, is cooled and then held for a prescribed set time in a furnace at the tempering temperature, and is further cooled to normal temperature by natural cooling, wherein the heating temperature of the forged material is set in the range of 1150 to 1250 deg.C.
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