Gray Cast iron VS Ductile iron
Gray Cast iron VS Ductile iron
(OP)
For diaphragm valve lined with PTFE, I understand that the fluid will not contact body material. I would like to use gray cast iron instead of ductile iron. Are there any disadvantages for this applicatoin.





RE: Gray Cast iron VS Ductile iron
RE: Gray Cast iron VS Ductile iron
The only set of rules that should concern you is the design code that governs your installation.
Both ASME B31.1 and B31.3 put limitations on use of cast iron in toxic, flammable and steam service. Limitations imposed typically are in the form of pressure/temperature maxima or inclusion only in non-shock service.
If a material is deemed suitable for service (by the piping code) and the component is design rated for that combination of temperature and pressure, then you should be able to use it. Valve manufacturers have excellent experience with succesful and non-successful installations and are usually happy to share it with a customer..
MJC
RE: Gray Cast iron VS Ductile iron
RE: Gray Cast iron VS Ductile iron
Why should you consider cast iron. It will not save you money. The standard for any valve manufacturer is ductile.
My advise, stick to the standard material configuration.
ood luck !
Ed
RE: Gray Cast iron VS Ductile iron
For critical service I would always use DI over CI. I beleive that Saunders diaphragm valves are only available in CI but other manufacturers such as Kim or Gemu could well have DI. Of course you would expect to pay more for a DI bodied valve. But this will be a lot less than the repair of a cracked flange.
RE: Gray Cast iron VS Ductile iron