ASTM A403 Stainless Pipe Fitting

ASTM A403 Pipe Fittings

Scope of ASTM A403:

  • This specification covers wrought stainless steel fittings for pressure piping applications .
  • Several grade of austenitic stainless steel alloy are included in this specification grades are designated with a prefix , WP or CR , based on the applicable ASME or MSS dimensional and rating standard, respectively .
  • For each of the WP stainless grades , several classes of fittings are covered , to indicate whether seamless or welded construction was utilized . Class designations are also utilized to indicate the non-destructive test method and extent of non-destructive examination (NDE) . Table 1 is a general summary of the fitting classes applicable to all WP grade of stainless steel covered by this specification . There are covered elsewhere.
  • This specification is expressed in both inch-pound units and in SI units . However, unless the order specifies the applicable “M” specification designation (SI uints), the material shall be furnished to inch-pound units .
  • The values stated in either SI units or inch-pound units are to be regarded separately as standard . Within the text , the SI units are shown in brackets . The values stated in each system may not be exact equivalents ; therefore , each system shall be used independently of the order . Combining values form the two systems may result in non-conformance with the standard .
  • This specification does not apply to cast steel fittings . Austenitic stainless steel castings are covered in specifications A351/A351M , A743/A743M , and A744/A744M
Chemical Composition (%) of ASTM A403
Grade UNS C Mn P S Si Ni Cr Mo
304 S30400 0.008 2.00 0.045 0.030 1.00 8.0-11.0 18.0-20.0 -
304H S30409 0.04-0.10 2.00 0.045 0.030 1.00 8.0-11.0 18.0-20.0 -
304L S30403 0.035 2.00 0.045 0.030 1.00 8.0-13.0 18.0-20.0 -
304LN S30453 0.030 2.00 0.045 0.030 0.75 8.0-10.5 18.0-20.0 -
304N S30451 0.08 2.00 0.045 0.030 0.75 8.0-11.0 18.0-20.0 -
309 S30900 0.15 2.00 0.045 0.030 1.00 12.0-15.0 22.0-24.0 -
310 S31000 0.15 2.00 0.045 0.030 1.50 19.0-22.0 24.0-26.0 -
316 S31600 0.08 2.00 0.045 0.030 1.00 10.0-14.0 16.0-18.0 2.00-3.00
316H S31609 0.04-0.10 2.00 0.045 0.030 1.00 10.0-14.0 16.0-18.0 2.00-3.00
316LN S31653 0.030 2.00 0.045 0.030 0.75 11.0-14.0 16.0-18.0 2.00-3.00
316L S31603 0.035 2.00 0.045 0.030 1.00 10.0-16.0 16.0-18.0 2.00-3.00
316N S31651 0.008 2.00 0.045 0.030 1.00 11.0-14.0 16.0-18.0 2.00-3.00
317 S31700 0.008 2.00 0.045 0.030 1.00 11.0-15.0 18.0-20.0 3.0-4.0
317L S31703 0.030 2.00 0.045 0.030 1.00 1.0011.0-15.0 18.0-20.0 3.0-4.0
321 S32100 0.008 2.00 0.045 0.030 1.00 9.0-13.0 17.0-20.0 -
321H S32109 0.04-0.10 2.00 0.045 0.030 1.00 9.0-13.0 17.0-20.0 -
347 S34700 0.08 2.00 0.045 0.030 1.00 9.0-13.0 17.0-20.0 -
347H S34709 0.04-0.10 2.00 0.045 0.030 1.00 9.0-13.0 17.0-20.0 -
348 S34800 0.008 2.00 0.045 0.030 1.00 9.0-13.0 17.0-20.0 -
348H S34809 0.04-0.010 2.00 0.045 0.030 1.00 9.0-13.0 17.0-20.0 -
XM-19 S20910 0.060 4.0-6.0 0.040 0.030 1.00 11.5-13.5 20.5-23.5 1.5-3.00
  S31254 0.020 1.00 0.030 0.010 0.80 17.5-18.5 19.5-20.5 6.0-6.5
  S31725 0.030 2.00 0.045 0.030 0.75 13.5-17.5 18.0-20.0 4.0-5.0
  S31726 0.030 2.00 0.045 0.030 0.75 13.5-17.5 17.0-20.0 4.0-5.0
  S34565 0.030 5.0-7.0 0.030 0.010 1.00 16.0-18.0 23.0-25.0 4.0-5.0
  S33228 0.004-0.008 1.0 0.020 0.015 0.30 31.0-33.0 26.0-28.0 -
Mechanical Properties of ASTM A403
Grade UNS Tensile Strength, min Yield Strength,min Elongation min % in 4D
ksi MPa ksi MPa Longit % Trans%
ALL ALL 75 515 30 205 28 20
304L S30403 70 485 25 170 28 20
316L S31603 70 485 25 170 28 20
304N S30451 80 550 35 240 28 20
316N S31651 80 550 35 240 28 20
  S31726 80 550 35 240 28 20
XM-19 S20910 100 690 55 380 28 20
  S31254 94-119 650-820 44 300 28 20
  S34565 115 795 60 415 28 20
  S33228 73 500 27 185 28 20
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