定义有效的外壳深度，并指定确定该深度的方法（以钢为单位）。适用于渗碳层和渗碳层，深度大于0.3 mm，以及距离表面3 X有效层深度处硬度小于450 HV的零件。

Defines the effective case depth, and specifies methods for the determination of this depth, in steel. Is applicable to carburized cases and carbo-nitrided cases, the depth of which is greater than 0,3 mm, and parts which have a hardness of less than 450 HV at a distance of 3 X the effective case depth from the surface.