316SS or Hastelloy C A494 for Operation T up to 500F 1

[carol2005]

Need to install a Pressure/Vacuum Relief valve on a vessel. Normal operating temperature is as high as 500F. Wondering what material is good for the Pressure/Vacuum Relief Valve? 316 Stainless Steel or Hastelloy C A494? Or select other materials? Thank you for your suggestions.

 

[JLSeagull]

The fluid composition is as important as the pressure and temperature regarding material compatibility. Begin with the material used in the associated vessel trim or piping specifications. Perhaps carbon steel is suitable. Stainless might be the next alloy to consider before any of the nickel based alloys.

 

[carol2005]

The venting fluid would be hot Nitrogen and operating pressure is below 10 bar.

 

[carol2005]

Gasket for the vent is another concern. I need to contact the vendors for information.

 

[carol2005]

Thank you,JLSeagull. WHich material is better for high temperature? SS or Hastelloy?

 

[JLSeagull]

Refer to ASME B16.5 for flange ratings, cross reference your alloy preference to UNS numbers. To do this search the alloy by name and “UNS”. Hastelloy C-276 cross references to UNS N10276. Searching ASME B16.5 for 10276 reflects ASTM B 462. This would be found on table 2-3.8. In this case 500 degree F and Class 300 flange is rated 665 psig.

See 2.2 for A 182 Grade F316. Looking at table F2-2.2 for deg F find that 500 degree F a Class 300 type 316 SSt flange is good to 480 psig and the pressure drops to a maximum of 1500 degree F.

In this example Class 300 flanges are rated for higher pressure in Hastelloy C-276 than for type 316 stainless steel.

See 2-3.X for some of the nickel alloys such as B 564. Hastelloy includes ASTM B 366, B 564, B 572, B 581, etc. Looking at F2-3.2 at 500 degree F find that B 160 grade N02200 Class 300 is limited to 455 and only published to 600 degree F. N02201 Class 300 is only rated 255 psig at 500 degree F. Table 3.3 is published to 1200 F. Table F2-3.6 for N08800 Class 300 500 degree F is rated 600 psig and published to 1500.

 

[0707]

carol2005

For your case with a temperature of 260ºC and in nitrogen service I think 316 Stainless Steel would be enough.