Questions regarding bolts/nuts made of the following two materials
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Question: Can 35CrMoA GB3077-99 stud bolts/35# GB699-99 HVY.HEX.S.F nuts with cadmium plating be used interchangeably with A93 Gr.B7 stud bolts/A194 Gr.2H HVY.HEX.S.F nuts with galvanized and PTFE coating in the connection of carbon steel pipelines or stainless steel pipelines? Why? Are there corresponding national standard materials for these two types of bolts and nuts? Thank you
The one that meets American standards is A193. Both can be used on C.S and S.S pipelines. Firstly, bolts of 35CrMoA GB3077-99 can be replaced by those of A193, and nuts of 35# GB699-99 can be replaced by those of A194 Gr.2H; the latter are American standard materials. The former is a replacement for the national standard. Finally, your national standard version is cadmium-plated, while the American standard versions are galvanized or PTFE-coated; it depends on which type is required for your project. Basically, the two are equivalent. If cost is a concern, just use whichever one is cheaper.
The one above is A193 Gr.B7