Liner is the part that is used as bedding for billet during extrusion process and placed inside the container. The liner is the part that is exposed to heat, friction and therefore the erosion the most during
extrusion process. Erosion and heat transformation resistance of the liner material must have the desired quality. Although various special materials can be used, hot work tool steels, primarily 1.2344 and 1.2367, are preferred. In order to lengthen the liner life and prevent possible extrusion errors, the liner must be checked and maintained every six months. Technical specifications of 1.2344: is a kind of steel whose toughness is high, resistant to thermal shocks, wear resistance at high temperatures is high, and thermal conductance is high. Technical specifications of 1.2367: mechanical specifications at high temperatures are better than 1.2343 and 1.2344. This is a steel whose efficiency is high when compared to 2344 with regard to stretching ability and wearing resistance.