What kinds of waterproof washers are commonly used for screws?

Editor:Jiaxing UNITEK Machinery Technology Co., Ltd. │ Release Time:2021-11-11 

PVC gasket (polyvinyl chloride):

Generally transparent or translucent, it has strong resistance to oxidants, reducing agents and strong acids. However, it can be corroded by concentrated oxidizing acids such as concentrated sulfuric acid and concentrated nitric acid and is not suitable for contact with aromatic hydrocarbons and chlorinated hydrocarbons. It is a low-end product with poor UV resistance, aging resistance, high temperature and low temperature resistance. It is generally used in conjunction with carbon steel drill nails, and does not match the life of 410 drill nails, generally after one or two severe winters. It will age; the PVC gaskets used by our company are made of new materials, not recycled materials;

EPDM monomer gasket:

EPDM (Ethylene-Propylene-Diene Monomer) is generally available in gray and black. The most important feature is its superior resistance to oxidation, ozone and corrosion, aging resistance, water resistance, corrosion resistance, and electrical resistance. Insulation, high temperature resistance, low temperature resistance, and good elasticity. Depending on the content of EPDM, the price is also different. There are foamed EPDM gaskets with a content of up to 60% on the glass;

EPDM one-piece gasket:

That is, the metal plate and the EPDM rubber are bonded together. Please pay attention to the following points:

1. The material of the metal plate is usually galvanized plate, aluminum alloy, SUS430, SUS304, SUS316;

2. The thickness of the metal plate is usually 1.0mm and 0.7mm;

3. The outer diameter of the gasket, generally ST4.8 screws are matched with gaskets with outer diameter of Φ14mm, ST5.5 screws are matched with gaskets with outer diameter of Φ16mm, ST6.3 screws are matched with gaskets with outer diameter of Φ16mm, and 19mm, 25mm are also available. Gasket

Our company's method of expressing the specifications of conjoined gaskets is: screw specification*gasket outer diameter* (metal plate thickness + EPDM rubber plate thickness) such as: ST5.5*16mm*(0.7+2.2)

There are also mushroom-type EPDM gaskets with better water resistance

Neoprene gasket:

High tensile strength, excellent heat resistance, light resistance, and aging resistance. Oil resistance is better than natural rubber, styrene butadiene rubber, butadiene rubber. It has strong flame resistance and excellent flame retardancy, and its chemical stability is relatively good. High, good water resistance, the shortcomings of chloroprene rubber is electrical insulation performance, poor cold resistance, chloroprene rubber gasket also has two forms of monomer and conjoined.