我厂某产品中有一零件采用20钢钢管扩孔后拉铰成型,光洁度要求▽6,因该零件对强度、硬度无特殊要求,若不经热处理或900～920℃正火后光洁度都达不到要求;若采用900～920℃加热,10%盐水中冷却,回火到 HRC25～30,虽拉铰后光洁度能达到要求,但工件扭曲变形严重;采用780～800℃加热后预冷的亚温淬火和900～920℃加热预冷至暗红色(约45～60秒)盐水中快冷,250℃ I plant a product of a part of the 20 steel pipe reaming after the reaming molding, finish requirements ▽ 6, because the parts of the strength, hardness no special requirements, if not by heat treatment or 900 ~ 920 ℃ after the normalized fire are not reached To the requirements; if the use of 900 ~ 920 ℃ heating, 10% brine cooling, tempering HRC25 ~ 30, although the pull hinge finish to meet the requirements, but serious distortion of the workpiece distortion; Quenching and 900 ~ 920 ℃ heating precooling to dark red (about 45 ~ 60 seconds) brine fast cooling, 250 ℃