Why is stainless steel chosen as the material for expansion joints?

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The materials used for expansion joints are often austenitic stainless steels (304, 304L, 321, 316, 316L). 1. Stainless steel requires less corrosion allowance, allowing the expansion joint to be thinner while still providing a large amount of single-wave compensation. 2. For the same service life (number of cycles), the allowable stress range for stainless steel expansion joints is higher than that for carbon steel expansion joints, being 130% to 180% of the latter’s value. 3. The plasticity of stainless steel is twice that of carbon steel, which facilitates cold forming. 4. Carbon steel or low-alloy steel expansion joints are suitable for temperatures up to ≤375°C, while stainless steel expansion joints are suitable for temperatures up to ≤500°C. 5. If the corrosion allowance > 1 mm, use a stainless steel expansion joint. 6. If the temperature exceeds 550°C, use high-alloy steel.