Carbon (c): Carbon is essential for heat treatment process with the increases in carbon content the attainable hardness also increases but in hot work steels the maximum carbon content is limited to 0.35 in order to improve shock resistance.

Chromium (cr): chromium improves hardness resistance to heat checking and resistance

to correct.

Silicon (si) & manganese (mn): if added in small quantities improve hardness and heat resistance properties.

Tungsten (w): this improves the heat resistance of steel if a minimum of 4 is present. Unfortunately tungsten decreases the heat conductivity of die steel. This is a major disadvantage the amount of tungsten required can be reduced if other alloying element like molybdenum and vanadium are present.

Molybdenum (mo): this improves heat resistance with out any decrease in thermal conductivity. To obtain same quality as tungsten only 1/3 quantity of mo is sufficient. It also prevents grain growth. Vanadium (v): it improves heat resistance and hardness even if it is present in one small quantities (0.3 -0.5) provided other alloying element like tungsten and molybdenum are present the addition of vanadium in the H13grade steel has given higher resistance to surface erosion. Vanadium also prevents grain growth and promotes fine grain structure.