Dissimilar Seat Materials
Dissimilar Seat Materials
(OP)
I am considering replacing the seat material on a parallel slide gate disk with a 300 series stainless steel overlay. The seat ring in the valve is a bronze material, vintage 1930. Would you expect any wear or other issues associated with using these dissimilar metals in this design. Valve is not in a severe service or in service where dielectric isolation would be a consideration.





RE: Dissimilar Seat Materials
... A very cautious,no,????? (Others?), perhaps depending on fluid. If seawater for instance, SS might not be the best in itself.
It would probably help your 'answer rate' if you gave more information: existing material replaced, other details, size, apllication, operational pressures etc.
RE: Dissimilar Seat Materials
RE: Dissimilar Seat Materials
... size? Somhow I believe you are talking about fairly large valves, perhaps above 24 inches? Smaller?
For this aplication in Europe, depending on placement/exact service and size, at least for 24 inches and below, a typical modern replacement would be gatevalves with complete rubber-lined gate, body in nodular cast iron, epoxy coated body and top inside and outside (250-300my), selected from top-quality producers and top models.
A good alternative is high-quality knife-gate valves (ss quality knife, nodular cast iron housing, epoxy coated (also here certified surface coating)) which would also be chaper and lighter for sizes 12 inches and up, and if actuated.
Other alternatives for new valves exists, and complete new valves and pipeline should anyway be considered as an alternativ to repair, with cost/lifetime calculations for complete renewal alternatives compared to overhaul and repair.
Apart from this, I do not think you will have problems with your material combination, repair done properly, but I could be wrong. This is more a material/metallurgical/corrosion problem. You could perhaps try to present this in a material-oriented forum?
RE: Dissimilar Seat Materials
But I'd say you're okay, as long as you get a good, parallel lap job on the sealing surfaces.