For hydrogen sulfide-resistant valves, is it better to anneal first and then process them, or to process them first and then anneal?
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This post was last edited by niuuinioo on 2010-7-14 at 16:10. In several recent CNPC projects, the need for hydrogen sulfide resistance in pipeline valves for flammable gases has been mentioned; we would like to share our company’s treatment methods for discussion. When selecting castings or forgings, we primarily opt for low-carbon types; the components inside the valve and those in contact with the medium are subjected to annealing treatment to reduce their hardness. Minimize scoring on the inner wall of the valve body to ensure its integrity. Sulfur crystals tend to form in the valve body gaskets; it is recommended to use materials with good corrosion resistance for these gaskets, and users should be advised to inspect and replace them regularly. I have a question for everyone: should the cast valve body be annealed first and then processed, or processed first and then annealed?
If a gas-liquid separator is needed, please contact me
Is “Huzi” on the second floor the equipment manufacturer?
An annealing step should still be carried out first; it’s not because of whether it’s necessary or not, but heat treatment generally causes changes in the dimensional specifications. Although these changes are not significant, if processing is done before the material has returned to room temperature, the required precision levels will certainly not be achieved.