Nominal Seating Surface, Stem and Backseat Bushing or Weld-deposit Materials and Hardness

Note

Cr = Chromium; Ni = Nickel; Co = Cobalt; Cu = Copper; NA = Not Applicable

Trim materials, including stem and base material for HF trim items shall have a corrosion resistance and temperature limit at least equal to the valve body’s corrosion resistance and pressure temperature rating.

• aHB (formerly BHN) is the symbol for the Brinell hardness as per ASTM E10.
• bFee machining grades of 13Cr are prohibited.
• cBody and gate seat surfaces should be 250 HB minimum with a 50 HB minimum differential between the body and gate seat surface.
• dManufacturer’s standard Hardness.
• eDifferential hardness between the body gate seat surface is not required
• fCase hardness by nitriding to a thickness of 0.13 mm (0.005 In.) minimum.
• gThis classification includes such trademark materials as satellite 6™, Stoody 6™, and wallex 6™
• hManufacturer’s standard hardfacing with a maximum iron content of 25%
• iHardness differential between the body and gate seat surfaces shall be the manufacturer’s standard
• jNot used
• kManufacturer’s standard with 30 Ni minimum
• lNot used
• mTypical backseat weld deposit material
• nPer manufacture’s standard if not hardfaced 250 HB minimum if hardfaced

*This term is used as an example only, and does not constitute an endorsement of this product by API.

Trim Material Equivalent Grades