| 摘要 |
PURPOSE:To manufacture parts for carburization treatment without austenitic grain growth, by specifing a heating temperature at final forging when the parts treated with carburization from the carbon steel containing a specified proportion of aluminum, titanium, nitrogen and boron. CONSTITUTION:When parts treated by carburization are manufactured from carbon steel or low alloy steel of 0.015-0.07wt% aluminum, 0.007-0.07wt% titanium and 0.01-0.03wt% nitrogen, further of being regulated at 0.0005max. wt% boron, the heating temperature at the final forging is made to be 1,180 deg.C min. Thereby, through high temperature carburization of about 950 deg.C min. is treated, the austenitic grain is not coarsened and strength or the like is not reduced. Further, though each carbon steel or low alloy steel for use contains carbon, silicon and manganese according to the process of refining or the like thereof, they are generally regulated at 0.1-0.4wt% carbon, 0.05-0.15wt% silicon and 0.05-2.0wt% manganese. |
