Welded

  • Standard pipe lengths are about 20 feet long (SRL) or about 40 feet long (DRL).
  • Pipes are identified by nominal pipe size (NPS). For sizes 1/8” through 12”, the actual outside diameter is larger than the corresponding NPS while the outside diameter for sizes 14” and up are the same as the NPS. Please consult the pipe chart for dimensional information.
  • To obtain the working pressure, take the required information from the Product Dimensions Chart table and use Barlow’s Formula at the bottom of this page.

Additional Information

The information presented above are typical or average values and are not a guarantee of maximum or minimum values

A/SA 312 Permissible variations in outside diameter
Nom. pipe size ins. TOLERANCE
PLUS MINUS
1/8 to 1-1/2, incl. 1/64 (0.015) 1/32 (0.031)
Over 1-1/2 to 4, incl. 1/32 (0.031) 1/32 (0.031)
Over 4 to 8, incl. 1/16 (0.062) 1/32 (0.031)
Over 8 to 18, incl. 3/32 (0.093) 1/32 (0.031)
Over 18 to 24, incl. 1/8 (0.125) 1/32 (0.031)
Seamless and Welded Austenitic Stainless Steel Pipe have a minimum wall thickness that at any point shall not be more than 12.5 per cent under the nominal wall thickness specified.

See ASTM A999 for additional information.

ASTM/ASME Designation

Title
A/SA 312 Specification for Seamless and Welded Austenitic Stainless Steel Pipe.
A/SA 358 Specification for Electric-Fusion-Welded Austenitic Chromium-Nickel Alloy Steel Pipe for High-Temperature Service
A/SA 376 Specification for Seamless Austenitic Stainless Steel Pipe for High-Temperature Central-Station Service
A/SA 409 Specification for Welded Large Diameter Austenitic Stainless Steel Pipe for Corrosive or High-Temperature Service
A 778 Specification for Welded Unannealed Stainless Steel Pipe

 

Barlow’s Formula for Theoretical Bursting Pressure
P = 2 (S * T) / O.D.
P – Bursting Pressure (P.S.I.) T – Wall Thickness (Inches)
O.D. – Outside Diameter (Inches) S – Tensile Strength

Typical Tensile Strengths (S)
Stainless Steel (300 Series) S = 70000 to 75000 psi
Chrome Moly (P1 to P5) S = 55000 psi
Chrome Moly (Balance) S = 60000 psi
Alloy 20 S = 80000 psi
904L S = 70000 psi
Duplex s = 90000 psi

 

A/SA 358 Welded Pipe
Electric Fusion Welded Austenitic Chromium Nickel Alloy Steel Pipe for High Temperature Service

Five classes of pipe are covered as follows:

  • Class 1 – Pipe shall be double welded by processes employing filler metal in all passes and shall be completely radiographed.
  • Class 2 – Pipe shall be double welded by processes employing filler metal in all passes. No radiography is required.
  • Class 3 – Pipe shall be single welded by processes employing filler metal in all passes and shall be completely radiographed.
  • Class 4 – Same as class 3 except that the weld pass exposed to the inside pipe surface may be made without the addition of filler metal (see 5.2.2.1 and 5.2.2.2).
  • Class 5 – Pipe shall be double welded by processes employing filler metal in all passes and shall be spot radiographed.
Permissible variations in wall dimensions

Permissible Variations – The dimensions at any point in a length of pipe shall not exceed the following:

  • Outside Diameter – Based on circumferential measurement, ± 0.5% of the specified outside diameter.
  • Out-of-Roundness – Difference between major and minor outside diameters, 1%.
  • Alignment – Using a 10-ft or 3-m straightedge placed so that both ends are in contact with the pipe, 1/8 in. (3mm).
  • Thickness – The minimum wall thickness at any point in the pipe shall not be more than 0.01 in. (0.3mm) under the nominal thickness.
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