Help: Valve specification replacement
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Medium: K2CO3+KHCO3 solution at around 90 degrees Celsius (crystallization may occur). The specifications required by the design institute are as follows: TRIM:13Cr/HF (API#8). The specifications proposed for substitution are as follows: TRIM:13Cr (F6a CL.2). Question: The main difference lies in the presence of HF or not; is it possible to use the alternative specification under these operating conditions? Thank you
13Cr denotes the material of the valve body; it contains 13% chromium and is a martensitic stainless steel. National standard code — 1Cr13 ； FH refers to the material of the valve sealing surface. The American Petroleum Institute provides the following specifications: Table 13 in API 600 contains information related to the sealing surface; 1 Cr = chromium ； Ni=Nickel ； Co=cobalt ； Mo=molybdenum. 2 HF=Harden the surface using CoCr or NiCr welding alloys. Suffix A is applicable to NiCr. HF means hard face. It should be surface hardening treatment, which involves using a certain material. Given the possibility of crystallization, it is recommended to use HFD
Trim, the internal components of a valve, including the valve core, valve stem, valve seat, etc
According to the API600 design standards, internals type 8 and 8A can replace internal type 1! ! ! No problem! ! Moreover, the inner component No. 8 is of semi-STL type, providing a performance that better meets the requirements of your application conditions.
Thank you. What I mean is to replace the specifications originally required by the design institute with the ones below – is that possible?
Number 8 can replace number 1, but number 1 cannot replace number 8. Although it’s just a matter of additional STL files, in reality number 1 is inferior to number 8, so it definitely won’t work! The design institute won’t agree to such a substitution either! !
You can go and ask in the soda ash section; their physical and chemical properties are similar, as they are both carbonates of alkali metals
My understanding is that the requirement for HF is intended to improve the sealing effect, and it has nothing to do with corrosion resistance. But in general, lower grades (without HF requirements) cannot be used as a substitute for higher grades (with HF requirements)
HF hardening treatment is necessary because of the possibility of crystallization; theoretically, it is not possible to do without this hardening treatment. Besides, it’s just surfacing with STL; it shouldn’t be much more expensive, right?