The Extrusion Stem must withstand the total deformation resistance of the material being extruded.The occurring extrusion loads result in very high compressive and partly bending stresses in the stem.

Although the pressure pads prevent the stem from having direct contact with the hot billet, the stem head can be exposed to excessive temperature by the heat radiated from the liner and transferred via the pressure pad. In addition to high stresses, these conditions define the demands on special steels.

Steels for such use are shown in the table below.