The bolts on the manholes and observation doors of stainless steel equipment cannot be removed
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I would like to ask everyone: are the bolts used for manholes and observation doors on stainless steel equipment usually made of stainless steel as well? Since these doors need to be opened frequently, could they get stuck and become impossible to remove?:dizzy::dizzy:?
Generally made of carbon steel, with galvanizing for corrosion protection. Some money can be saved on the project. We will change it to 304 to save on labor costs for anti-corrosion treatment. For manhole bolts at normal temperatures with a diameter of DN500 or larger, using 304 bolts prevents jamming. But once the temperature exceeds 100°C, never disassemble it while it’s hot; you can first cool it with cold water before proceeding with the disassembly. The observation door is the same in other aspects; whether it can be removed depends on the ambient temperature of the bolts.
It is possible, but it is still necessary to follow the original design, and carbon steel bolts cannot be replaced arbitrarily. This is because stainless steel and carbon steel have issues related to rusting. There are also proper methods to remove bolts, for reference.
Using carbon steel will suffice; add stainless steel gaskets at the contact points between the nut and the flange