Analysis of Factors Affecting Opening and Closing Torque of Globe Valve
Jan. 19, 2026
Opening and closing torque is a key indicator to judge whether a globe valve is easy to operate and runs stably. If the torque is abnormal, it is likely to cause problems such as stem deformation and poor sealing. There are mainly three types of factors affecting it: valve structure, material characteristics, and working conditions.
1. Valve Structure Design Factors
The type of sealing surface directly determines the frictional resistance: flat sealing has a large contact area, requiring slightly higher torque; conical or spherical sealing is line or point contact, resulting in smaller torque. Moreover, the smoother the sealing surface, the smaller the torque generated by friction. The transmission structure of the stem also has a significant impact. The thread of an outside screw stem valve is exposed, making lubrication easy, and its torque is smaller than that of an inside screw stem valve, whose thread is hidden inside the valve body, prone to corrosion by the medium and higher resistance. In addition, the larger the nominal diameter of the globe valve, the greater the medium thrust on the disc, and the torque will increase accordingly; the torque fluctuation of a straight-through flow channel is smaller than that of a right-angle flow channel, as right-angle flow channels are prone to eddy currents and increased resistance.
2. Material Characteristic Factors
The material matching of the sealing surface is crucial: metal-to-metal pairing has a high friction coefficient, requiring large torque but with good high-temperature resistance and wear resistance; metal-to-nonmetal pairing has a low friction coefficient, small torque, and is suitable for globe valves in medium and low-pressure scenarios. Selecting a combination of a copper alloy nut and a stainless steel stem can help reduce friction. Regular lubrication with grease in daily use can also avoid dry friction—once the grease fails, the torque will increase sharply. If the rigidity of the valve body material is insufficient, it is prone to deformation, which in turn affects coaxiality and increases lateral friction. Cast steel valve bodies offer better rigidity than cast iron ones, resulting in stronger torque stability for the globe valve.
3. Working Condition Factors
The higher the medium pressure, the greater the thrust on the disc, and the torque will naturally rise. The torque of a high-pressure globe valve is much larger than that of a low-pressure one. High temperature accelerates material thermal expansion and grease aging, while low temperature may cause thread jamming—both conditions will increase torque. High-viscosity media generate viscous resistance, corrosive media aggravate surface wear, and solid-containing media cause abrasive wear. All three conditions will increase torque and even jam the stem. Valves that have been closed for a long time are prone to scaling and adhesion on the sealing surface, requiring greater torque when opening again; the torque of opening and closing a globe valve under pressure is much higher than that under no pressure, as it is necessary to overcome both frictional resistance and medium thrust.
4. Other Factors
If the coaxiality deviation is too large during installation, it will cause uneven stress on the stem and generate lateral bending moment, thereby increasing opening and closing resistance. Doing a good job in daily maintenance, such as regularly cleaning impurities, replacing grease, and repairing worn threads, can ensure the long-term stability of the globe valve’s torque and reduce the occurrence of faults.
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