Chemical Composition Requirements of MSS SP 75
Elements | Value, % |
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 |
Titanium(Ti) | ≤0.05 |
*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 Class | Yield Strength | Tensile Strength | Elongation | Charpy Test |
Min. psi | Min. psi | min. % | Ave. Energy absorbed @ 20°F | |
WPHY-42 | 42000 | 60000 | 25 | ≥20ft*lbs |
WPHY-46 | 46000 | 63000 | 25 | |
WPHY-52 | 52000 | 66000 | 25 | |
WPHY-56 | 56000 | 71000 | 20 | |
WPHY-60 | 60000 | 75000 | 20 | |
WPHY-65 | 65000 | 77000 | 20 | |
WPHY-70 | 70000 | 82000 | 18 |
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.
