Manhole bolt material
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As shown in the diagram, both the manhole cover and the tower body are made of stainless steel, but the bolts seem to be made of carbon steel. I’ve read posts before stating that carbon steel can cause carburization, which leads to electrochemical corrosion of the stainless steel. Is it necessary to use stainless steel for these bolts? I’m a beginner in this field and seeking advice.
Carbon steel bolts, with anti-corrosion treatment. In the picture, it seems that the protective layer has come off after the threads were tightened, right?
It’s just those few bolts; just replace them with stainless steel
In accordance with standards and contract requirements. The contract can be above standard! Safety first!
For manhole standards in the chemical industry, carbon steel is recommended; it depends on the application scenario
The device has been left unused for a year, and its anti-corrosion coating has long since worn off…
Since this manhole cover is made of stainless steel, I think it’s necessary to use stainless steel bolts, but I can’t find any standard specifications for them
All the equipment is already made of white steel; it just lacks the money for those few white steel screws to complete the conversion to white steel
If there are no special requirements, galvanized ones will do
There are no special requirements; carbon steel screws are used for everything
The bolts do not come into contact with the medium and are not exposed to corrosive environments; it’s best to avoid using them if possible