Valves are constructed of a variety of media - this section will cover the typical valve steel grades, elastomers and trims used in industry.
Each steel grade has certain chemical or mechanical requirements - these grades result in different potential applications. In valve applications, stainless steel is typically considered a premium (though other high end special alloys exist), followed by low temp then reg temp. Given the characteristics of each steel grade stainless steel valves can be used as a substitute for low temp and reg temp valves - low temp valves can also be used as a substitute for reg temp valves in most applications. Click on a grade/section for more information.
ASTM - American Society for Testing and Materials www.astm.org
As a quick guide here are the typical steel designations for the valve industry:
ASTM A216 - WCB/WCC - cast steel good for regular temp applications -20*F to 800*F
ASTM A352 - LCB/LCC - low temp cast steel good for low temp applications -50*F to 800*F
ASTM A351 - CF8M - cast stainless steel good for absolute zero to 1500* F
ASTM A182 - 316SS - forged stainless steel good for absolute zero to 1500* F
A105 - forged steel good for regular temp applications -20*F to 800*F
ASTM A350 - LF2 - low temp forged steel good for low temp applications -50*f to 800*F
ASTM A276-410 - Click her for more information on this common steel grade used in gate, globe and check valves.
Specialty Trims - The grades covered above are the common grades; click here for information on other alloys.
Heat Treatment - Heat treatments are used to change the properties of steel; click here for more information.
Elastomers are the seats and seals of the valve industry. Having the right elastomer can make the difference of a valve failing or lasting years in service. Elastomers typically have a lower melting/critical temperature than steel and knowing about them can go a long way to choosing the right valve. Keep in mind that like steel, elastomers come in a variety of grades and variations with different mechanical/chemical properties. Click here to view a chemical resistance chart detailing what media is good for what elastomers. (link to chemical resistance chart)
Click here to view more information on common elastomers used in the valve industry.
Gate, globe and check valves are often referred to as having a specific trim; the trim is a number that determines what material is used on the gate, disc, or sealing portion of a valve. Click here to view the API trim chart.
Chemical Resistance Chart
Contact - The Valve Pipeline
Check valves have a "cracking pressure" or a minimum upstream pressure at which the valve will operate.