Stem is the part that realizes the pressure by transmitting the force of main piston to the billet through Dummy Block or Thrust Washer. The stem material must have high toughness and homogenous hardness. The quality of stem depends on heat treating method and quality as much as the used material. Special mechanic- metallurgical designs can be performed depending on the specification of the alloy that is extruded. Technical specifications of 1.2343: Its hardness is lower than 32HRB. Since its thermal conductivity is better at high temperatures, its endurance against thermal shocks and corrosions is high.