Most of our BPR’s are made from stainless steel Type 316 alloy (SS316) or Type 316L (SS316L) for excellent corrosion resistance to most chemicals. These pressure regulators are machined from cold rolled bar-stock, and are frequently in stock for sizes 1/2 and smaller. Regulators with welded connections are typically provided with stainless steel 316L low-carbon alloy. Our regulators can also be machined from SS304 and Hastelloy upon customer request.
Stainess steel regulator bodies can be fitted with a variety of diaphragms, such as fluoroelastomer (Viton), PTFE, PEEK, and SS316 itself (primarily for higher pressure applications).
Type 316 Stainless Steel
Type 316 Stainless Steel is a prominent member of the austentitic stainless steels. The addition of Molybdenum give SS316 an overall superior corrosion resistance than SS304 (especially for pitting and crevice corrosion in chloride environments). It is resistant to a wide range of chemicals, including acids, bases, solvents, and marine environments.
While a strong majority of chemicals are suitable for SS316, examples of chemicals that have a severe effect on SS316 are Hydrofluoric Acid, Hydrochloric Acid, Hydrobromic Acid, Ethyl Sulfate, Copper Chloride, Ferric Chloride, Phosphoric Acid, Sulfuric Acid , Silver Bromide, Aqua Regia, Sodium Hypochlorite, Sodium Sulfide.
The Cole-Parmer Chemical Compatibility Database () is an excellent reference. For clients with chemicals that are not compatible with SS316, Equilibar offers regulators made from Hastelloy and 100% PTFE.
Low Carbon SS316L
Stainless steel 316L (SS316L) has the same chemical composition as SS316, except that the carbon content is specified to be in a low and tighter range:
- SS316: <= 0.08% Carbon
- SS316L: 0.03% to 0.04% Carbon
While the chemical resistance of SS316 and SS316L is considered to be similar for machined components, Grade 316L’s lower carbon content is needed to prevent a reduction in corrosion resistance in the heat affected zone around welds. SS316L is equivalent to Type A4 in ISO 3506.
Equilibar’s back pressure valves are typically machined from cold rolled bar stock of Stainless Steel 316, though often of round bars dual certified as both Grade SS316 and 316L. All of our regulators with welded end fittings, including our hygienic regulators are made from SS316L.
Stainless steel 316 is the most common material for Equilibar back pressure regulators. Sizes 1/2 and smaller are often available in stock from SS316.