316L Stainless Steel Sheet and Pipe: Specifications and Production Guide

Standards and Designations

316L is a low-carbon molybdenum-bearing austenitic stainless steel. Sheet, plate and strip are specified under ASTM A240/ASME SA240 (UNS S31603), bars under ASTM A276, seamless and welded pipe under ASTM A312 (TP316L), boiler and superheater tubes under ASTM A213, and general-purpose tubing under ASTM A269. The European designation is 1.4404 (X2CrNiMo17-12-2) per EN 10088, the Japanese designation is SUS316L per JIS G4303-G4305, and the Chinese designation is 022Cr17Ni12Mo2 per GB/T 3280 and GB/T 14976. Related molybdenum-bearing grades in the same family include 316 (1.4401), 316Ti (1.4571), 1.4432 and 1.4435.

Chemical Composition and Mechanical Properties

The composition limits below follow ASTM A240.

Element (wt %)	316L (S31603)
Carbon, max	0.03
Manganese, max	2.0
Silicon, max	0.75
Phosphorus, max	0.045
Sulfur, max	0.030
Chromium	16.0-18.0
Nickel	10.0-14.0
Molybdenum	2.0-3.0
Nitrogen, max	0.10

Minimum mechanical properties for annealed sheet and plate per ASTM A240, and for seamless and welded pipe per ASTM A312, are listed below.

Property	A240 sheet/plate	A312 TP316L pipe
Tensile strength, min (MPa)	485	485
0.2% yield strength, min (MPa)	170	170
Elongation, min (%)	40	35

The low carbon limit of 0.03% prevents chromium carbide precipitation at grain boundaries during welding, so 316L does not need post-weld heat treatment to maintain corrosion resistance in heavy welded structures.

Manufacturing Routes and Surface Finishes

Sheet and coil are produced by hot rolling followed by cold rolling and bright or batch annealing; typical surface finishes are 2B, 2D, BA, No.4, HL and mirror, with pickling and passivation applied after annealing. Seamless pipe is manufactured by hot piercing or extrusion followed by cold drawing or cold rolling to the required dimension. Welded pipe is formed from strip and joined by electric resistance welding, electric fusion welding or double submerged arc welding for large diameters. After welding, pipe is solution annealed and pickled to restore corrosion resistance, then straightened and tested. Typical welded pipe dimensions cover outside diameters from about 12.7 mm up to 2200 mm in larger structural sizes, while seamless pipe commonly ranges from about 3 mm to 630 mm outside diameter with wall thicknesses from 1 mm to 50 mm; square and rectangular hollow sections are produced in similar size ranges for structural use.

Sizes, Tolerances and Testing

Standard length is 6 m or as required. Typical dimensional tolerances for precision-drawn tube are outside diameter plus or minus 0.2 mm, wall thickness plus or minus 0.02 mm and length plus or minus 5 mm, with tighter classes available on request. Ends are supplied plain, beveled, or threaded with coupling. Routine testing includes chemical analysis, tensile testing, flattening and flaring tests, hydrostatic testing, eddy current or ultrasonic examination, and positive material identification on critical batches. Mill test certificates report the actual heat chemistry and mechanical results, and independent third-party inspection can be arranged to the purchaser's specification.

Typical Applications and Selection

316L is used where 304 does not provide enough chloride resistance: seawater piping and heat exchangers, coastal architectural panels and handrails, chemical and pharmaceutical process equipment, food and beverage plants, medical devices, and welded storage tanks for mildly corrosive liquids. Select 316L for welded components that cannot be annealed after fabrication; choose 316 (1.4401) where the higher minimum strength of 515 MPa is required and post-weld annealing is performed, and 316Ti (1.4571) where stabilization is preferred for long-term high-temperature service.

Frequently Asked Questions

What is the difference between 316 and 316L? Carbon content: 316L limits carbon to 0.03% max versus 0.08% max for 316, which eliminates sensitization during welding; the minimum strength of 316L is slightly lower.

Is 316L pipe suitable for seawater? 316L resists chloride pitting better than 304 and is used in coastal and marine service, but for severe or stagnant seawater conditions duplex grades such as UNS S32205 are often specified.

Can 316L sheet be welded without heat treatment? Yes, this is the main advantage of the low-carbon grade; no post-weld heat treatment is required to restore corrosion resistance.

What surface finishes are available for 316L sheet? Common finishes include 2B, 2D, BA, No.4, HL and mirror, supplied annealed and pickled or polished.

How is 316L pipe tested? Standard tests include hydrostatic or eddy current examination, tensile testing, flattening and flaring, with positive material identification and mill test certificates provided per order.

What is the Chinese equivalent of 316L? The GB/T designation is 022Cr17Ni12Mo2, and the European and Japanese equivalents are 1.4404 and SUS316L.

Frequently Asked Questions

Q1. Which standards cover 316L sheet and pipe?
Sheet, plate and strip are specified under ASTM A240/ASME SA240 (UNS S31603), bars under ASTM A276, seamless and welded pipe under ASTM A312 (TP316L), boiler and superheater tubes under ASTM A213 and general-purpose tubing under ASTM A269; the European designation is 1.4404 (X2CrNiMo17-12-2) per EN 10088.

Q2. What are the composition limits of 316L?
Per ASTM A240: carbon 0.03 max, manganese 2.0 max, silicon 0.75 max, phosphorus 0.045 max, sulfur 0.030 max, chromium 16.0-18.0, nickel 10.0-14.0, molybdenum 2.0-3.0 and nitrogen 0.10 max; the Chinese designation is 022Cr17Ni12Mo2 per GB/T 3280 and GB/T 14976.

Q3. What are the minimum mechanical properties?
For annealed sheet and plate per ASTM A240 and for seamless and welded pipe per ASTM A312, tensile strength is 485 MPa minimum and 0.2 percent yield strength is 170 MPa minimum, with 40 percent minimum elongation for sheet and plate and 35 percent for pipe.

Q4. How are 316L sheet and pipe manufactured?
Sheet and coil are hot rolled, cold rolled and bright or batch annealed with finishes such as 2B, 2D, BA, No.4, HL and mirror; seamless pipe is hot pierced or extruded then cold drawn or cold rolled, and welded pipe is formed from strip and joined by electric resistance, electric fusion or double submerged arc welding, then solution annealed and pickled.

Q5. What dimensions and tolerances apply to 316L tube?
Welded pipe covers outside diameters from about 12.7 mm up to 2200 mm, while seamless pipe commonly ranges from about 3 mm to 630 mm outside diameter with wall thicknesses from 1 mm to 50 mm; precision-drawn tube is typically supplied with outside diameter plus or minus 0.2 mm, wall thickness plus or minus 0.02 mm and length plus or minus 5 mm, in a standard length of 6 m.