The stem of a control valve serves as the critical, high-precision link between the valve actuator and the flow-controlling element (plug, ball, or disc). Its core function is to transmit actuator force into precise linear or rotary motion, directly dictating the orifice area and thus the flow rate. Unlike isolation valves, a control valve stem operates continuously within a dynamic range, making its performance, accuracy, and longevity paramount for stable process control, efficiency, and safety.
Extreme corrosion & specialty applications: Duplex and Super Duplex stainless steels provide strength and chloride resistance. Exotic alloys like Monel, Inconel X-750, and Hastelloy are specified for highly corrosive, high-temperature, or nuclear environments. Titanium may be used for its exceptional strength-to-weight ratio and seawater resistance.
Commonly, austenitic stainless steels (304, 316/316L SS) are used. 316L is preferred for superior corrosion resistance and smooth surface finish, ideal for packing. Precipitation-hardening stainless steels such as 17-4PH offer higher strength and good corrosion resistance for high-thrust applications.
