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MSS SP75 WPHY Fittings

MSS SP-75 specification covers factory-made, seamless and electric welded carbon and low alloy steel, butt-welding fittings for use in high pressure gas and oil transmission and distribution systems, including pipelines, compressor stations, metering and regulating stations, and mains.

MSS SP 75 is the standard specification for high-test, wrought, butt-welding fittings which covers factory-made seamless and electric fusion-welded carbon and low-alloy steel butt-welding pipe fittings for use in high-pressure oil and gas transmission and distribution systems, including pipelines, compressor stations, metering and regulating stations, and mains.

In term of minimum yield strength, MSS SP 75 pipe fittings can be further categorized into 7 classes:

  • WPHY-42
  • WPHY-46
  • WPHY-52
  • WPHY-56
  • WPHY-60
  • WPHY-65
  • WPHY-70

“WP” is the abbreviation for “wrought pipe” or “wrought plate” while “HY” stands for “high yield”. These WPHY pipe fittings can be furnished as long-radius elbows, 3R elbows, straight tees, reducing tees, caps and reducers. They are usually used for the joint with API 5L pipes or ASTM A694 forged pipe flanges.

We Supplier this MSS SP75 WPHY Pipe Fittings in the following form.

At some point, with all the possibilities of thread form, diameter, and pitch, you need to send it off to SK Grimes or another machinist.


MSS(Manufacturers Standardization Society) is the only organization in the world dedicated exclusively to the technical needs of the valve and fittings industry.

Standards and codes are written and revised by 25 technical committees and address topics such as valves, valve actuators, pipe fittings, flanges, and pipe hangers.

Chemical Composition Requirements of MSS SP 75

ElementsValue, %
Carbon (C)≤0.30
Manganese (Mn)≤1.60
Phosphorus (P)≤0.035
Sulfur (S)≤0.035
Copper (Cu)≤0.50
Nickel (Ni)≤0.50
Silicon (Si)≤0.50
Chromium (Cr)≤0.25
Molybdenum (Mo)≤0.13
Vanadium (V)≤0.13
Columbium (Cb)≤0.10

*1. The sum of Cu, Ni, Cr and Mo shall not exceed 1%.
*2. Carbon equivalent C.E.=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15 shall not exceed 0.45%.

Mechanical Properties of MSS SP 75 Pipe Fittings
MSS SP 75 ClassYield StrengthTensile StrengthElongationCharpy Test
Min. psiMin. psimin. %Ave. Energy absorbed @ 20°F

MSS standard list for fittings


MSS SP-25Standard Marking System for Valves, Fittings, Flanges and Unions.
MSS SP-43Wrought Stainless Steel Butt Welding Fittings.
MSS SP-44Standard for Steel Pipe Line Flanges.
MSS SP-75Specification for High Test Wrought Butt Welding Fittings.
MSS SP-79Socket Welding Reducer Inserts.
MSS SP-83Carbon Steel Pipe Unions Socket welding and Threaded.
MSS SP-87Factory-Made Butt Welding Fittings for Class 1 Nuclear Piping Applications.
MSS SP-95Swage(d) Nipples and Bull Plugs.
MSS SP-97Integrally Reinforced Forged Branch Outlet Fittings-socket Welding, Threaded and Butt Welding Ends.

Material, Welding & Manufacture

The raw material of MSS SP 75 pipe fittings shall be fully killed steels made by either open hearth, basic oxygen, or electric furnace process. It consists of blooms, billets, slabs, forging quality bar, plate, seamless or fusion-welded pipes. The welding processes shall be conducted in accordance with Section IX of ASME Boiler and Pressure Vessel Code, or related ASTM & API specifications. Post-weld heat treatment shall be taken in accordance with the requirements of Section VIII, Division 1 of ASME Boiler and Pressure Vessel Code. The welding ends (bevels) of the fitting shall be furnished differently in terms of wall thickness.The MSS SP 75 WPHY pipe fittings may be readily manufactured by forging, hammering, pressing, piercing, rolling, extruding, upsetting, welding, or by a combination of these processes. Finished products shall be free of injurious defect or welding-repair. Machining and grinding of surface defects may be required by some clients.

Heat Treatment

Pipe fittings manufactured to MSS SP 75 shall be furnished in the heat treated condition. Hot formed fittings shall be cooled below the lower critical temperature prior to heat treatment. Fittings shall be heat treated by one or more of the following procedures: annealing (stress relieving), normalizing, normalizing and tempering, quenching and tempering.

Tests and Examinations

The tests and examinations available for WPHY fittings includes hydrostatic test(proof test), tensile tests, PMI(spectrum), Charpy test, radiographic examination(X-Rays, RT), magnetic particles inspection(MPI), ultrasonic examination(UT), Liquid Penetration Examination(LPE), etc.

Dimensions and Tolerances

MSS SP 75 only specifies the dimensions and tolerances for pipe fittings sized from NPS 16 (DN 400) through NPS 60 (DN 1500). Dimensional requirements for NPS 14 and smaller are provided by reference to ASME B 16.9.