The valve stem is an important part of the valve. It is used to drive, connect the actuating mechanism or handle, and directly drive the spool to move or rotate, so as to realize the function of valve switch or regulation.Valve stem in the valve opening and closing process is not only moving parts, stress components, but also seals. At the same time, it is subjected to the impact and corrosion of the medium, and it also causes friction with the packing. Therefore, in selecting the stem material, it must be guaranteed that it has sufficient strength at the prescribed temperature, good impact toughness, scratch resistance, corrosion resistance. The valve stem is a vulnerable part, and the mechanical performance and heat treatment performance of the material should be paid attention to when selecting.The valve stem in the valve opening and closing process, under tension, compression and torsion force, and direct contact with the media, as well as the relative motion between the friction and filler, so in the choice of stem material, must ensure that it provides adequate temperature strength, good impact toughness, abrasion resistance and corrosion resistance of.