Regarding the material of the bolts used at pipe flange connections
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What material should be used for bolts at the flange connections of stainless steel (304/316L/310S) pipes? Do stainless steel bolts also need to be used? Can 35CrMo be used? (Will such bolts rust over time and cause corrosion to the stainless steel?) Thank you
If stainless steel bolts are used with stainless steel flanges, it is easy for galling to occur
If stainless steel bolts are used with stainless steel flanges, it is easy for galling to occur
The 304 flanges used in our low-temperature applications are all fitted with 304 stainless steel bolts, and no abnormalities have occurred
The bolts and nuts of stainless steel valves are generally made of stainless steel as well
Reply to 1# Sponge hm: Generally, stainless steel pipe flanges are connected using stainless steel bolts. If stainless steel and carbon steel are placed together for an extended period of time, potential corrosion can occur. However, I’ve seen people do this: they use black bolts and nuts with stainless steel pipes, and the valves as well as their bodies and covers are made of stainless steel, while the connecting bolts are made of carbon steel!
35CrMo bolts can be used, especially under high temperature and high pressure conditions. At normal temperature and pressure, stainless steel is used. It depends on the medium, temperature, pressure, and environment. Handle each situation on its own.
We all use A193 B7 or B7M bolts, zinc-plated with PTFE