Asme 16.20 gasket material 1

[Liftingengineer]

I am looking to simplify the gasketing process for my maintance department. Our spec and stock vary between the 4 winding materials 304, 304L, 316, 316L and the fillers PTFE and Graphite. Does anyone know the reasoning if there is a different in the use of the different Stainless steels? My current believe is that the L does not matter, and also 316 will outperform 304.

 

[numberfive]

Take a look at the attached Spiral Wound Gastket Specification Sheet - I commonly refer to this

 

[jtseng123]

"L" does matter, and generally 316 is better than 304.
All gasket materials used are purely based on the "service" of each equipment. You can not arbitrarily substitute one with the other without consulting to a material engineer who also familiar with the service.
Gasket supplier, such as Flexitallic, will be able to give you a guideline based on service. Contact them first. "Pressure vessel handbook" by Megyesy, has a section talking about chemical resistance of gaskets for your reference.

 

[jnich]

There's definitely a difference, but it may not matter depending on your application. Both 316 and 316L will outperform 304 regarding corrosion-resistance. 316L has a slightly lower strength (SMYS & UTS) compared to 316, but is easier to weld and will resist corrosion better compared to welded 316. The client I've worked with only allows spiral-wound gaskets for high-pressure piping applications. Interestingly enough, the vendor I've always worked with (Flexitallic) only offers 316L windings for their CGI-style spiral-wound gaskets. I'm not sure why that is though.

 

[tothepoint]

Flexitallic and all SW gasket manufacturers produce inner ring (CGI style) spiral wound gaskets in both 316 and 304 metallurgy. Fact.
Confirm that your service is chemically compatible with either 304 or 316 an then standardize on one if compatibility allows.
Do you need both PTFE and Flexible Graphite fillers? Can you standardize on one; preferably FG?
Don't specify and use CGI (inner ring) style SW gaskets unless you have problems created by inward buckling. Inner rings double or triple the price of the SW gasket, they can protrude into the pipe bore creating turbulence, and they make the gasket much stiffer requiring higher assembly bolt loads to seat the gasket.
If inward buckling is an issue you should evaluate anti-buckling SW gasket designs: Garlock EDGE or AB-326