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Diaphragm Seal Materials

Diaphragm Seal Materials
Diaphragm Seal Elements

Mansfield & Green brand diaphragm seals are constructed of materials suitable for all types of applications and process media. Utmost care should be exercised when specifying to insure material compatibility with your specific requirement.

Tantalum-clad stainless steel is available in flange attached seal elements only. 304L and 316L stainless steel is used in all seals that are welded in the field. Other materials are available on special request.

Mansfield & Green diaphragm seals can be equipped with an AMETEK USG gauge or furnished for an application with any brand and model pressure transmitter or pressure switch.


Mansfield & Green diaphragm seals are available in a wide variety of materials so that you can select the optimum seal element that is compatible with your specific process requirement.

Diaphragm seals utilize a thin, highly compliant or flexible diaphragm between the process medium and the pressure containing internals of the pressure instrument. These diaphragm materials are compatible with the process media and include the following materials: 304L SST; 316L SST; Hastelloy C276, C22 or B; Inconel 600 or 625; Monel 400; Kalrez 1050; Neoprene; Tantalum; TEFLON; Titanium; Viton; and many others. Please contact your distributor or USG customer service for more information at or +1 215-293-4100.

Upper Housing
The standard upper housing material for Mansfield & Green diaphragm seals is carbon steel, zinc-plated for better corrosion resistance. Optional 316L stainless steel and other materials are also available, such as MONEL, Hastelloy, Titanium, etc.

Lower Housing
Selection of the correct lower housing material is especially important since this part of the seal is directly exposed to the process media. As a general rule, materials chosen are normally of the same type as used in the remainder of the piping system.

Lower housing material options include:
  • Carbon Steel
  • 304L Stainless Steel
  • 316L Stainless Steel
  • Titanium
  • Carpenter 20 Stainless
  • MONEL 400
  • Nickel 200
  • Inconel 600
  • Inconel 625
  • PVC
  • Polyproprylene
  • Zirconium

    Type R Series removable metal diaphragms are selfgasketed by means of a TEFLON coating. No separate gasket is required.

    Standard Type S Series seals incorporate gasket material of non-asbestos aramid fiber. Glass-filled TEFLON and TEFLON-coated stainless steel gaskets are also available for Type S Series. Other materials are available on special request.

    Type SMJ and SNJ Series
    These seal elements are used in applications where there is a jacketed pipeline and where heated or cooled processes are involved. The Type SMJ conforms to Schedule 40 process pipe rating (other schedules available). Type SNJ seals meet ANSI flange pressure/temperature ratings.

    Mansfield & Green furnishes bolts and nuts with all thread-attached and In-Line Flow Thru seal elements. Standard bolt material is high-temperature alloy steel, Grade 41 BV 35 or equal, 105,000 psi minimum yield strength at 650°F (343°C); 316L stainless steel and other materials are available upon special request. Nuts are supplied in Type 18 stainless steel as standard. Other materials are available upon special request. AMETEK also supplies studs where required.

    The customer supplies bolts and nuts for all flange attached seals. All seals with TEFLON gaskets or diaphragms should be torqued to 10 ft. lbs., aramid and elastomer gaskets to 20-25 ft. lbs., and metal gaskets to 40-45 ft. lbs. All bolts should be lubricated prior to installation.

    Fill Fluids
    Specifiers should exercise extreme care in the selection of the proper fill fluid for specific applications since fill fluids may react chemically with process fluids and other materials. Compatibility of the selected fill fluid is the responsibility of the customer. Typical fill fluids are listed in this catalog and our distributor price book.