TABLE OF CONTENTS For most process applications, the materials of construction can be accommodated to fit both the corrosive-erosive and mechanical strength requirements. Manufacturers have established standard materials, which will fit a large percentage of the applications, and often only a few parts need to be changed to adapt the valve to a corrosive service. Typical standard parts are (see Figures 9-3a, 9-3b, and 9-4) as follows:
| Option 1 (typical only) | |
| Body | carbon steel, SA 216, gr.WCB |
| Nozzle | 316 stainless steel |
| Disk/Seat | stainless steel |
| BlowDown | Ring 300 Ser. stainless steel |
| Stem or Spindle | stainless steel |
| Spring | C.S.rust proof or high temp.alloy, rust proof |
| Bonnet | SA-216, gr.WCB carbon steel |
| Bellows | 316L stainless steel |
| Option 2 (typical only) | |
| Body | 316 stainless steel |
| Nozzle | 17-4 stainless steel or 316 stainless steel |
| Disk/Seat | Teflon, Kel-F, Vespel or Buna-N |
| BlowDown Ring | 316 stainless steel |
| Stem or Spindle | 17-4 stainless steel or 316 SS |
| Spring | 316 stainless steel |
| Bonnet | 316 stainless steel |
| Bellows |
For pressure and temperature ratings, the manufacturers' catalogs must be consulted. In high pressure and/or temperature, the materials are adjusted to the service.
For chemical service the necessary parts are available in 3.5% nickel steel; Monel; Hastelloy C; Stainless Type 316, 304, and so on.; plastic-coated bellows; nickel; silver; nickel-plated springs; and other workable materials.
The designer must examine the specific valve selected for a service and evaluate the materials of construction in contact with the process as well as in contact with...
