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ASTM A358 Specification

The ASTM A358 specification includes electric-fusion-welded austenitic chromium-nickel stainless steel pipe.  This pipe is suitable for corrosive, high-temperature service, and/or general applications.  The pipes are divided into five different classes:

  • Class 1 pipe is double welded by using filler metal in all passes and completely radiographed.
  • Class 2 pipes is double welded using filler metal in all passes with no radiography.
  • Class 3 pipes are single welded
  • Class 4 pipes are single welded, however the weld pass of Class 4 exposed to the inside pipe surface may be without filler metal addition.
  • Class 5 pipes are double welded using filler metal and is spot radiographed.


Weld defects are repaired by removal to sound metal and rewelding. Heat treatment is required on the original welds. The finished pipes undergo tension test, transverse guided-bend weld test, and hydrostatic test.

At Penn Stainless, all of our products can be ordered to ASTM, ASME, AMS, UNS, MILS, ANSI, and more.  Please see our product pages or contact us directly for more information.

Please see the  ASTM Site for additional information regardng this specification.

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