Is 13Cr+STL for the valve seat, and 13Cr+STL for the valve disc/sphere acceptable? Does the internal component have to be a casting?
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Valve body and valve cover: A105; valve seat: 13Cr+STL; valve disc/sphere: 13Cr+STL; valve stem: 13Cr. Some technicians said it’s not acceptable – can’t the valve seat be made of 13Cr with the sealing surface made of STL? The valve body and valve cover are CF8, while the seat, valve disc/sphere, and valve stem are 304. Is it not acceptable either? It must be that both the valve body and valve cover are CF8, and the seat and valve disc/sphere as well, is that right? Is this how it’s written in many compounds? Is the valve body a cast component, and must the internal parts as well be cast? Please give some feedback.
This technician is wrong; the material of the valve internals can be of the same grade or a higher grade than that of the valve body. Generally speaking, carbon steel valve bodies can be paired with stainless steel internals, whereas stainless steel internals cannot be used with carbon steel internals. Specifically, you can refer to the internal component numbers and material pairings in API600.
What this technician is saying isn’t correct; the valve body is made of cast CF8, while the valve disc/sphere and valve stem can be either CF8 or 304.
The material selection for valves requires that the material of the valve’s internal components be no lower than that of the valve body.
Previously, the valve body was made of cast material, while the internal components were not cast. We have used both of these that the original poster is using before. . . I asked the manufacturer, and they said there was no problem. .
You can check the pipeline grade specifications for LPEC online; the fourth edition can be found on Baidu. In any case, what was said is incorrect
Some design institutes use this approach; we had a project last time with a similar composition – the valve body was made of WCB, the gate was made of 1CR13, and STL was used for surfacing. In fact, some people from design institutes have not fully understood the requirements of the API600 internal component standards. F6 refers to materials such as 1CR13. But there’s nothing to do about it; the manufacturer follows customer opinions.