A312 PIPE SPECIFICATION (GRADES 304/L & 316/L)

Scope

This specification covers seamless, straight-seam welded, and heavily cold worked welded stainless steel pipe intended for high-temperature and general corrosive service.

Process

Pipe to be manufactured Seamless, Welded or Heavily Cold Worked

Chemical Requirements

GradeUNS #Content % by weight
CarbonManganesePhosphorusSulfurSiliconChromiumNickelMolybdenum
TP304S304000.082.000.0450.0301.0018 – 208 – 11x
TP304LS304030.0352.000.0450.0301.0018 – 208 – 13x
TP316S316000.082.000.0450.0301.0016 – 1810 – 142 – 3
TP316LS316030.0352.000.0450.0301.0016 – 1810 – 142 – 3

Permitted Variations in Wall Thickness

Tolerance, % from Nominal
NPS DesignatorOverUnder
⅛ to 2½ incl., all t/D ratios20.012.5
3 to 18 incl., t/D up to 5% incl.22.512.5
3 to 18 incl., t/D > 5% incl.15.012.5
20 and larger, welded, all t/D ratios17.512.5
20 and larger, seamless, t/D up to 5% incl.22.512.5
20 and larger, seamless, t/D > 5%15.012.5

where:

t = Nominal Wall Thickness

D = Ordered Outside Diameter

  • Exception for welded pipe: the weld area shall not be limited by the “Over” tolerance

Permitted Variations in Outside Diameter 

NPS DesignatorPermissible Variations in Outside DiameterDN DesignatorPermissible Variations in Outside Diameter
Over
in.
Under
in.
Over
[mm]
Under
[mm]
⅛ – 1½, incl164 (0.015)132 (0.031)[6–40], incl[0.4][0.8]
Over 1½ to 4, incl132 (0.031)132 (0.031)Over [40 to 100][0.8][0.8]
Over 4 to 8, incl116 (0.062)132 (0.031)Over [100 to 200][1.6][0.8]
Over 8 to 18, incl332 (0.093)132 (0.031)Over [200 to 450][2.4][0.8]
Over 18 to 26, incl⅛ (0.125)132 (0.031)Over [450 to 650][3.2][0.8]
Over 26 to 34, incl532 (0.156)132 (0.031)Over [650 to 850][4.0][0.8]
Over 34 to 48, incl316 (0.187)132 (0.031)Over [850 to 1200][4.8][0.8]

Heat Treatment

All pipe shall be furnished in the heat-treated condition

Heat treat temperature for 304/L and 316/L is 1900 deg F (1040 deg C) minimum and then quenched in water or rapidly cooled.

Tensile Requirements

GRADE
304
GRADE
304L
GRADE
316
GRADE
316L
Tensile Strength, minimum PSI75,00070,00075,00070,000
Yield Strength, minimum PSI30,00025,00030,00025,000

Hydrostatic or Nondestructive Electric Test

Each pipe shall be subjected to the nondestructive electric test or the hydrostatic test. The type of test to be used will be at the option of the manufacturer unless otherwise specified in the purchase order.

Referenced Documents

ASTM Standards

ASME Standards:

  • B1.20.1 Pipe Threads, General Purpose
  • B36.10M Welded and Seamless Wrought Steel Pipe
  • B36.19 Stainless Steel Pipe
  • ASME Boiler and Pressure Vessel Code: Section VIII4