The carbon content of carburized steel is generally very low (between 0.15% and 0.25%), which is a kind of low carbon steel. Such carbon content ensures that the core of carburized parts has good toughness and plasticity.
In order to improve the strength of the steel core, a certain amount of alloy elements, such as Cr, Ni, Mn, Mo, W, Ti, B, can be added to the steel.
The main role of Cr, Mn, Ni and other alloy elements is to increase the hardenability of the steel, so that the surface and core structures are strengthened after quenching and low temperature tempering.
In addition, a small amount of Mo, W, Ti and other carbides can form stable alloy carbides, which can refine grains and inhibit overheating of steel during carburizing.
A small amount of B (0.001% ~ 0.004%) can strongly increase the hardenability of the alloyed carburized steel.
