Depth of hardness of steel is increased by addition of

Solution (By Examveda Team)

Depth of hardness refers to how deeply into the steel hardness can extend after a hardening process such as quenching. This property is linked to the hardenability of the steel.

Chromium is the most effective alloying element for increasing the depth of hardness. It improves the steel’s hardenability by slowing down the transformation of austenite to softer phases, allowing martensite to form deeper within the material. This ensures that not just the surface but also the interior can achieve significant hardness.

Nickel improves toughness and corrosion resistance but has little effect on depth of hardness.

Tungsten increases wear resistance and hot hardness (retention of hardness at high temperatures), but it is less effective for depth of hardness compared to chromium.

Vanadium refines grain size and enhances wear resistance, but its influence on hardenability depth is secondary.

Therefore, Chromium is the alloying element most responsible for increasing the depth of hardness of steel.