__________ addition increases the depth of hardness of steel.

Solution (By Examveda Team)

Tungsten is a strong carbide-forming element that significantly increases the depth of hardness in steel. When added, tungsten forms stable carbides that penetrate deeper into the steel structure during heat treatment, allowing hardness to extend well below the surface. This makes tungsten especially important in tool steels and high-speed steels, where deep and lasting hardness is required.

Chromium: Improves corrosion resistance and surface hardness, but its primary role is not increasing hardening depth.

Nickel: Enhances toughness and strength, but contributes little to the depth of hardening.

Vanadium: Refines grain size and improves wear resistance, but its effect on hardening depth is less pronounced compared to tungsten.

Therefore, Tungsten is the correct element that increases the depth of hardness of steel.