The commonly used bolt materials for stainless steel flanges include stainless steel 304, stainless steel 316, stainless steel 321, etc. The selection of these materials mainly depends on the specific usage environment and requirements. Stainless steel 304 contains 18% chromium and 8% nickel, and has good corrosion resistance, suitable for general corrosive environments; Stainless steel 316 contains 17% chromium and 12% nickel, with the addition of 2% molybdenum, providing superior corrosion resistance and making it particularly suitable for marine and chemical environments; Stainless steel 321 contains 18% chromium and 8% nickel, with the addition of 5% molybdenum and titanium, exhibiting excellent high temperature and corrosion resistance.
When selecting bolt materials, it is necessary to consider the usage environment, material compatibility, and potential corrosion issues. Carbon steel bolts and stainless steel flanges may experience galvanic corrosion when in contact, especially in humid or chemical environments, which can lead to rapid corrosion of carbon steel bolts, reducing the safety and service life of the connection. Therefore, from a long-term safety perspective, it is recommended to choose stainless steel bolts that are similar in material to the flange, especially in situations with high temperature, high humidity, or chemical media.
In addition, under severe cyclic conditions such as reciprocating compressor pipelines and PSA separation, it is recommended to use alloy steel materials instead of stainless steel bolts. This is because stainless steel bolts are prone to fatigue fracture when subjected to large alternating stress amplitudes, posing significant safety hazards. Therefore, choosing the appropriate bolt material needs to be determined based on specific usage conditions and safety requirements.