A/SA350 Low Temp Forged Fittings & Flanges Specification

American Piping Products stocks A/SA350 forged fittings and flanges for low-temperature pressure systems in the following grades:

  • A/SA350-LF2 CL1 / CL2
  • A/SA350-LF3 CL1


ASTM A350 & ASME SA350 covers several grades of carbon and low-alloy steel forged or ring-rolled flanges, forged fittings and valves intended primarily for low-temperature service and requiring notch toughness testing. They are made to specified dimensions, or to dimensional standards, such as the ASME and API specifications.  Product furnished to this specification shall conform to the requirements of specification A961/A961M.


The steel shall be produced by any of the following primary processes: Open-hearth, basic-oxygen, electric-furnace or vacuum-induction melting (VIM). The steel shall be fully killed, fine-grain practice. The molten steel may be vacuum treated prior to or during pouring of the ingot. Material for forgings shall consist of ingots or forged, rolled, or strandcast blooms, billets, slabs or bars.

Heat treatment

After hot working and before reheating for heat treatment, the forging shall be allowed to cool substantially below the transformation range. Forgings of grades other than Grade LF787 shall be furnished in the normalized, or in the normalized and tempered, or in the quenched and tempered condition.

Chemical requirements

Refer to carbon fitting and flange specification guide.

Mechanical properties

Refer to carbon fitting and flange specification guide.

Reference documents

  • ASTM A788/A788M Specification for Steel Forgings, General Requirements
  • ASTM A961/A961M Specification for Common Requirements for Steel Flanges, Forged Fittings, Valves, and Parts for Piping Applications
  • ASME B 16.5 Steel Pipe Flanges and Flanged Fittings
  • ASME B 16.9 Factory-Made Wrought Steel Butt-Welding Fittings
  • ASME B 16.10 Face-to-Face and End-to-End Dimensions of Ferrous Valves
  • ASME B 16.11 Forged Steel Fittings, Socket-Welding and Threaded
  • ASME B 16.30 Unfired Pressure Vessel Flange Dimensions
  • ASME B 16.34 Valves-Flanged, Threaded, and Welding End
  • ASME B 16.47 Large Diameter Steel Flanges