The valve stem, the English name valve stem , is an important part of the valve fittings. It is used for the transmission of the valve, the upper actuator or the handle. The valve core moves or rotates directly to realize the valve switching or regulating function.
The valve stem is not only a moving part, a force receiving part but also a sealing part during the opening and closing process of the valve. At the same time, it is subject to the impact and corrosion of the media and also creates friction with the filler. Therefore, when selecting the valve stem material, it must be ensured that it has sufficient strength, good impact toughness, scratch resistance and corrosion resistance at the specified temperature. The valve stem is a wearing part, and the mechanical processing property and heat treatment performance of the material should also be paid attention to when selecting.
Stem type
The valve stem types are: globe valve stem, gate valve stem series, ball valve stem, butterfly valve stem, safety valve stem, oil field valve stem, forged steel valve stem, marine valve stem, soft sealing stem, stainless steel Valve stem series, large valve stem, copper valve stem and other valve stems.
The stem nut and the valve stem are threaded to directly support the axial force of the valve stem, and the card is in friction with the valve member such as the bracket. Therefore, in addition to a certain strength, the stem nut requires a small friction coefficient, no rust, and does not bite with the valve stem.
At present, there are more than 200 valve stem manufacturers in China , and the valve stem company is gradually becoming bigger and the competition in the industry is increasing.
The new valve stem processing technology adopts self-made forging cold extrusion molding technology. The thread strength is high and the precision is accurate. The concentricity of the threaded part and the polished rod part are consistent, which overcomes the problems of the traditional chipless rolling thread, which is easy to be twisted, easy to deform, and vulnerable to the rolling die. The polished rod part adopts the technology to achieve the mirror effect, and the opening and closing is easier, the sealing performance is good, and then the key part is closed by the CNC one-shot molding, which is tensile and torsion-resistant, and ensures the quality of the parts and components in many aspects. .
First, the valve stem is made of self-made forging and cold extrusion. The thread strength is high and the precision is accurate. It completely solves the problem that the original valve stem thread adopts a spiral flying knife, and the thread precision is not accurate.
Second, the concentricity of the threaded part and the polished rod part are consistent, which overcomes the long-standing problem of the domestic rolling process, which is easy to twist, easy to deform, and vulnerable to the rolling die.
Thirdly, the polished rod part adopts the technical precision to achieve the mirror effect, the opening and closing is easy, and the sealing performance is good, which solves the problem that the precision of the grinding rod of the original polished rod part is not high and takes a long time.
Fourthly, the cutting part adopts numerical control technology for one-time forming, high precision, good performance of inverted light sealing, and also eliminates the use of two clamping heads and inverted sealing in the original incision part. The concentricity is poor, the inverted sealing is easy to leak; the end part is divided by milling machine. It is a problem of dividing the degree of the disk and processing the slow process and taking a long time.
Fifth, the T -slot of the end part adopts the forging forming process, which has high efficiency and low cost. The whole production process of the valve stem has reached the international advanced level.
This new process not only has low processing cost of the stem screw, but also ensures the quality of the product parts and reduces the cost of the product; and the valve stem and the screw rod are assembled in the valve, so that the opening and closing torque of the valve is small, and the opening is easy, It is labor-saving and time-saving; the surface has good coaxiality and good sealing performance; it can resist bit, torsion, high strength and enhance valve life.
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