Explanation

The depth of hardened layer of steel obtained during quenching after austenitizing. It is usually specified that the depth of the hardened layer is from the surface of the specimen to 50% martensite (semi martensite). The hardenabilhy of steel can be expressed by the ideal critical diameter, or by the critical diameter obtained by quenching under certain cooling conditions, or by the curve of hardness of the sample changing with the distance from the water cooling end (hardenabilhy curve) during the end quenching test. The hardenabilhy of steel depends on the cooling rate of undercooled austenite, the chemical composition of austenite (type and content of solution alloy elements), grain size, homogenization degree, and the existence state of the second phase (including undissolved carbide and inclusion). The determination methods of hardenabilhy mainly include end burning method, fracture inspection method, etc.

Classification