Test the effective depth of the hardened layer

The method stipulates measuring Hv value with a load of 9.8N (1Kg. f), or a load of 4.9-49N (0.5-5Kg. f) can be used. Measure the diagonal length of the indentation at a magnification of 400 times.

bc=d1+［（d2-d1）×（H1-HG）］/（H1-H2）

The hardened layer, also known as the carburized layer, is a layer that gives low-carbon steel workpieces the surface layer of high carbon steel. After quenching and low-temperature tempering, the surface layer of the workpiece has high hardness and wear resistance, while the central part of the workpiece still maintains the toughness and plasticity of low-carbon steel.