The valve stem is not only the moving parts, the force parts, but also the seal during the valve opening and closing. At the same time, it is subjected to the impact and corrosion of the medium, and it also produces friction with the filler. Therefore, when selecting the stem material, it is necessary to ensure that it has sufficient strength, good impact toughness, abrasion resistance and corrosion resistance at the specified temperature. The valve stem is a vulnerable part, and the mechanical and heat treatment performance of the material should be paid attention to in the selection of the material.