一、问题的提出在生产中往往会碰到这种情况:有些截面小的工件(像细弹簧、小钻头、小丝锥),淬火后从表面到心部都呈灰色细瓷状,说明它们都硬了,全淬透了,但尺寸较大的工件则不然,仪表层呈灰色细瓷状,而心部却较粗糙,表明它们只表面淬硬,也就是没有全部硬化。 First, the problem raised In production often encounter this situation: some small section of the workpiece (like spring, small drill, small tap), after quenching from the surface to the heart are gray fine porcelain, indicating that they are Hard, fully hardened, but the larger workpiece is not the case, the instrument was gray fine porcelain, while the heart is rough, indicating that they only surface hardened, that is, not all hardened.