When choosing the material for gaskets, we should consider three parts: temperature, pressure, and medium. And the material can be classified as metallic material and non-metallic material.
Firstly, let us talk about metallic material:
- carbon steel:
the recommended working temperature can not exceed +538℃, especially when there’s oxidizing medium. Carbon steel material is not suitable for the environment with inorganic acid, neutral or acidic saline solution. Carbon steel gasket with the hardness of BN 120 is usually used for seal strong acid and alkali solution.
- Stainless steel 304 (1.4301 according to DIN standard):
The recommend max. working temperature is 760℃, it’s easy to be stress corrosion and grain boundary corrosion under the temperature of -196~538℃, and its max. hardness is BHN160.
- Stainless steel 304L (1.4306 according to DIN standard):
Its carbon content is less than 0.03% compared to SS304, and the recommended working max. working temperature is 760℃. Due to lower carbon contents, S304L performs better regarding the resistance of grain boundary corrosion.
- Stainless Steel 316 (1.4401/1.4436 according to DIN standard):
By adding 2% Mo in stainless steel SS304, SS316 improves its strength and resistance to corrosion. It has better creep resistance compared with other common stainless steel. The recommend max. working temperature is 760℃, and the gaskets’ max. hardness is 160BHN.
- Stainless steel 316L (1.4435 according to DIN standard):
The recommended continuing working temperature is 760~815℃. “L” means lower carbon contents which provide it with excellent resistance to stress and corrosion.
- Stainless Steel 321 (1.4541 according to DIN standard)
It is a kind of Ni-Cr-Mo stainless steel and its characteristics is similar to SS304. But with more Ti, S321 has better resistance to grain boundary corrosion and high-temperature strength.
- Stainless steel S347 (1.4550 according to DIN standard)
It is an 18-10 chromium/nickel austenitic stainless steel. Compared with SS321,it is added columbium with which the material has high-temperature resistance. The recommended max. working temperature is 870℃.
- Alloy 20 (UNS N08020):
It is made up of 45% Fe, 24% Ni, 20% Cr, a little Mo and Cu, suitable for the environment of sulfuric acid. Alloy 20 finds wide use in all phases of chemical processing. The recommend max. working temperature is 1093℃.
- Hastelloy C276 (UNS N10276):
Its recommended max. working temperature is 1093℃ and it has excellent corrosion resistance to all kinds of cold nitric acid or boiling nitric acid with concentration up to 70%, to hydrochloric acid and sulfuric acid, at the same time, it has perfect resistance to stress corrosion.
- Inconel 600 (UNS N06600):
It is a Ni-based alloy with 77% Ni. The recommended max. working temperature is 1093℃, INC600 is always used in the equipment which solves the problem resulted from stress corrosion due to its good strength under high temperature. And it provides excellent processing characteristics under low temperature.
- Inconel 625 (UNS N06600)
It is a nickel/chromium alloy and has outstanding corrosion resistance in a wide range of acid, neutral and alkaline applications. The max. working temperature is 1093℃.
- Inconel 800 (UNS N08800)
It contains 32% nickel and 20% chromium and 46% iron. It has excellent high-temperature resistance and the max. working temperature is 1093℃.
- Inconel 825 (UNS N08825)
It is also a nickel/chromium alloy with max. working temperature of 1093℃. It is resistant to hot acid and has outstanding resistance to stress corrosion cracking.
- Monel 400 (UNS N04400)
It has excellent corrosion resistance to most acids and alkalis except strong oxidizing acids with the max. working temperature of 815℃. It is not suitable for the environment with medium of fluoric acid, mercury chloride and mercury as there will be cracks on the material surfaces under stress in these medias.
Its max. working temperature is 1093℃. It has perfect resistance to corrosion and nitric acid corrosion and it is suitable for oxidation applications.
Then we can go to non-metallic material for manufacturing gaskets.
- Natural rubber (NR)
It is resistant to weak acids and alkalis, salt and chloride solutions, but it is not suitable for oil and solvents applications. The recommended working temperature range is: -57℃~+93℃.
- Neoprene Rubber (CR)
CR is a kind of composite rubber material that is suitable for use in a moderate corrosive environment, it has good resistance to commercial oils and fuels. The recommended working temperature is: -51℃~+121℃.
- NBR rubber
A kind of composite rubber and it has good resistance to oil, solvents, aromatic hydrocarbons, alkaline hydrocarbons, petroleum and natural gas in a comparatively wide range of temperatures. The recommended working temperature is: -51℃~+121℃.
- Viton Rubber
It has excellent heat resistance, media resistance, low compression permanent deformation, good elasticity, and long working life. Viton rubber can be used to manufacture a cylinder seal gasket, rubber bowl and rotary lip seal ring due to its high-temperature resistance and oil resistance. The recommended working temperature is: -40℃~+232℃.
- Silicon Rubber
It has outstanding resistance to high and low temperatures. It can be used at 150℃ for a very long time but without any seal performance changes, and also continuously work for 10,000 hours at 200℃. With the operating temperature range from -70℃~+260℃, Viton rubber gasket can still keep its unique elasticity and ozone and weather resistance.
- EPDM rubber
It can be used in chemical, portable water. The recommended working temperature is: -40℃~+120℃.
The graphite material can be jointed to manufacture big size gasket over 600mm or even 1000mm. It has excellent corrosion resistance to many acids, salts and organic compounds, heat transfer solutions and even high-temperature solutions. The material can be used as filling material and non-metallic tape for manufacturing spiral wound gasket or metal jacketed gasket.
It is suitable for high temperature and low-pressure applications, the recommended working temperature is 1093℃. It’s can be used as filler for spiral wound gasket and double jacketed gasket.
It has the characteristics of most plastic material and is resistant to chemicals, solvents, hydroxides and acids and alkalis. The recommended working temperature is: -95℃~+260℃.
We Ginseal still supply other materials for manufacturing sealing gaskets. Please feel free to contact us for more information or some technical support.