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Sealing surface and the valve body have similar thermal expansion coefficients

Update:30-04-2019
Summary:

The sealing surface of the valve should be resistant to […]

The sealing surface of the valve should be resistant to abrasion, corrosion, erosion, and abrasion. It has sufficient extrusion strength. It has sufficient oxidation resistance and thermal fatigue at high temperature. The sealing surface and the valve body have similar thermal expansion coefficients. Has good processing properties and weldability, and should be considered between price and material properties.

The sealing surface of the valve is divided into three types: metal sealing surface, soft sealing surface and sealant sealing.

The metal sealing surface is mainly used in the occasions of abrasion resistance, erosion resistance, scratch resistance and high temperature resistance. Wear can be divided into adhesive wear, abrasive wear, surface fatigue wear, erosion wear and abrasion.

1.Adhesive wear Adhesive wear is most common, resulting from the huge adhesion of the interface between the two solid materials on the valve sealing surface. When the sealing faces of the valves slide against each other, the joints are constantly contacted and broken, forming abrasive grains and causing wear.

2.Abrasive wear A rough, hard surface in the sealing surface of the valve that wears when sliding against a relatively soft surface. An effective way to control abrasive wear is to make the softer material harder.

3.Surface fatigue wear repeated cyclic loading and unloading will cause fatigue cracks on the surface or the underlying layer, eventually leading to surface damage, forming fragments and pits.

4.Erosion wear is produced by sharp particles flushing the sealing surface. It is similar to abrasive wear but has a rough surface.

5.Scratch the damage caused by friction during the relative movement of the sealing surface, which is caused by the unreasonable hardness difference of the sealing surface.

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