Metal gasket material selection

The choice of material for the gasket depends mainly on the following three factors: Temperature Pressure Medium 1. Carbon Steel: The recommended maximum working temperature does not exceed 538 ° C, especially when the media is oxidizing. High quality thin carbon steel is not suitable for use in plants that produce mineral acids, neutral or acidic salt solutions. Equipment suffering from hot water conditions has a very high accident rate if carbon steel is subjected to stresses. Carbon steel gaskets are commonly used for high concentrations of acids and many alkaline solutions. Brinell hardness of about 120. 2. 304 stainless steel 18-8 (18-20% chromium, nickel 8-10%), the maximum recommended operating temperature does not exceed 760 ℃. In the temperature -196 ~ 538 ℃ range, prone to stress corrosion and grain boundary corrosion. Brinell hardness 160. 3. 304L stainless steel carbon content of not more than 0.03%. Recommended maximum operating temperature does not exceed 760 ℃. Corrosion resistance similar to 304 stainless steel. Low carbon content reduces the precipitation of carbon from the crystal lattice, resistance to intergranular corrosion than 304 stainless steel. Brinell hardness of about 140. 4. 316 stainless steel 18-12 (18% chromium, 12% nickel), adding about 2% molybdenum in 304 stainless steel, when the temperature increases its strength and corrosion resistance increased. When the temperature is higher than other ordinary stainless steel creep resistance. Recommended maximum operating temperature does not exceed 760 ℃. Brinell hardness of about 160. 5. 316L stainless steel recommended maximum continuous working temperature does not exceed 760 ℃ ~ 815 ℃. Carbon content does not exceed that of 316 stainless steel with better resistance to stress and grain boundary corrosion. Brinell hardness of about 140. 6. 20 alloy 45% iron, 24% nickel, 20% chromium and a small amount of molybdenum and copper. Recommended maximum working temperature does not exceed 760 ℃ ~ 815 ℃. Particularly suitable for the manufacture of sulfuric acid corrosion-resistant equipment, Brinell hardness of about 160. 7. Aluminum Aluminum (content of not less than 99%). Aluminum has excellent corrosion resistance and processing properties, suitable for the manufacture of double clip gasket. Brinell hardness of about 35. Recommended maximum continuous working temperature does not exceed 426 ℃. 8. The composition of copper red copper is close to pure copper, which contains trace amounts of silver to increase its continuous operating temperature. Recommended maximum continuous working temperature does not exceed 260 ℃. Brinell hardness of about 80. 9. Brass (66% copper, 34% zinc) has good corrosion resistance under most operating conditions but is not suitable for acetic acid, ammonia, salt and acetylene. Recommended maximum continuous working temperature does not exceed 260 ℃. Brinell hardness of about 58. 10. Hastelloy B-2 (26-30% molybdenum, 62% nickel and 4-6% iron). Recommended maximum operating temperature does not exceed 1093 ℃. Has excellent heat resistance hydrochloric acid corrosion. Also has excellent resistance to wet hydrogen chloride gas corrosion, sulfuric acid, phosphoric acid and reducing salt solution corrosion. High strength at high temperatures. Brinell hardness of about 230. 11. Hastelloy C-276 16-18% Molybdenum, 13-17.5% Chromium, 3.7-5.3% Tungsten, 4.5-7% Iron, the rest being nickel). Recommended maximum operating temperature does not exceed 1093 ℃. Has excellent corrosion resistance. Cold nitric acid for various attempts or boiling nitric acid up to 70% has excellent corrosion resistance, good resistance to hydrochloric acid and sulfuric acid corrosion and excellent resistance to stress corrosion. Brinell hardness of about 210. 12. British Cornel 600 nickel-based alloy (77% nickel, 15% chromium and 7% iron). Recommended maximum operating temperature does not exceed 1093 ℃. High strength at high temperatures, typically used for equipment that needs to address stress corrosion issues. In the low temperature conditions, with excellent processing performance. Brinell hardness of about 150. 13. Monel 400 (30% copper, nickel recommended maximum continuous working temperature does not exceed 815 ° C. In addition to the strong oxidizing acid, most of the acid and alkali have excellent corrosion resistance in the fluoride acid, mercuric chloride, mercury medium easy Resulting in stress corrosion cracking, therefore, does not apply to the above medium is widely used in the manufacture of hydrofluoric acid equipment Brinell hardness of about 120. Titanium recommended maximum working temperature does not exceed 1093 ° C. Under high temperature conditions, with excellent Corrosion resistance. It is well-known that corrosion resistance to chloride ions is excellent in resistance to nitric acid corrosion over a wide range of temperatures and concentrations. Titanium is rarely used in most alkaline solutions and is suitable for use in oxidative service conditions. Brinell hardness About 216.