What Is ASME SA312 TP316L Material Pipe?

What ASME SA312 TP316L Designates

ASME SA312 is the ASME Boiler and Pressure Vessel Code specification for seamless, welded and heavily cold worked austenitic stainless steel pipe. It appears in Section II, Part A of the code and is technically identical to ASTM A312.

TP316L identifies the grade: a molybdenum-bearing austenitic stainless steel with a maximum carbon of 0.03%, recorded as UNS S31603 and corresponding to EN 1.4404 / X2CrNiMo17-12-2. The TP prefix marks the tube and pipe product form within the specification.

ASME SA312 and ASTM A312: How They Relate

The two documents share the same technical content. ASTM A312 is an industry specification, while ASME SA312 is the code adoption used when pressure equipment or piping is built to ASME rules. Chemistry, mechanical properties and test requirements are the same, so pipe certified to ASTM A312 is normally accepted as ASME SA312 and the reverse, subject to the governing design code.

Item	ASTM A312	ASME SA312
Issued by	ASTM International	ASME Boiler and Pressure Vessel Code, Section II, Part A
Grade and property requirements	TP304, TP316, TP316L and similar, with tabulated mechanical values	Identical
Typical route	Commercial procurement and general engineering	Code-stamped pressure equipment and piping systems

Seamless and Welded Manufacture

SA312 TP316L pipe is supplied in two forms, and the specification covers both.

Seamless: a solid billet is pierced, then hot worked and cold finished to size. With no longitudinal weld, seamless pipe is usually chosen for high pressure, high temperature and cyclic duty.

Welded: strip or plate is formed into a cylinder and longitudinally welded, then annealed and sized. Welded pipe covers a wide size range with shorter lead times, and the specification offers radiographic and other non-destructive test options.

Both forms are delivered in the solution annealed condition with the weld reinforcement controlled.

Chemical Composition and Mechanical Properties

Heat analysis limits for the TP316L grade are shown below; product analysis tolerances, slightly wider for some elements, are permitted by the specification.

Element	Limit, %
Carbon (C)	0.03 max
Manganese (Mn)	2.00 max
Silicon (Si)	1.00 max
Phosphorus (P)	0.045 max
Sulfur (S)	0.030 max
Chromium (Cr)	16.0 - 18.0
Nickel (Ni)	10.0 - 14.0
Molybdenum (Mo)	2.00 - 3.00
Nitrogen (N)	0.10 max

Property	Requirement
Tensile strength	485 MPa (70 ksi) min
Yield strength, 0.2% offset	170 MPa (25 ksi) min
Elongation in 2 in. (50 mm)	35% min
Hardness, Rockwell B	90 HRB max

These are minimum values for annealed pipe. Actual results are confirmed on the mill test certificate for each heat and lot.

Equivalent Standards, Grades and Typical Applications

Standard or grade	Description
ASTM A312 / ASME SA312	Seamless, welded and heavily cold worked austenitic stainless steel pipe
ASTM A213 / ASME SA213	Seamless ferritic and austenitic alloy steel boiler, superheater and heat exchanger tubes
EN 10216-5	Seamless steel tubes for pressure purposes, stainless steel technical delivery conditions
DIN 17458	Historic German standard for seamless stainless steel pressure pipe, superseded by EN 10216-5
GOST 9941-81	Seamless cold and warm deformed corrosion-resistant steel tubes
GOST 9940-81	Hot deformed seamless corrosion-resistant steel pipes
UNS S31603	Unified numbering system designation for the 316L grade
EN 1.4404 / X2CrNiMo17-12-2	European material number and designation for 316L

Typical duties for ASME SA312 TP316L pipe include:

Chemical and petrochemical process piping handling chlorides and organic acids

Heat exchanger shells, condensers and water boxes

Offshore and coastal piping exposed to chloride-bearing atmospheres

Sanitary and high-purity process lines in pharmaceutical and food plants

General pressure piping in power and utility installations

Frequently Asked Questions

Q: Is ASME SA312 TP316L the same material as ASTM A312 TP316L?
Yes. ASME SA312 is the code adoption of ASTM A312 and the technical requirements are identical, so both designations describe the same pipe.

Q: What does the S in SA312 indicate?
The S prefix marks a specification adopted into the ASME Boiler and Pressure Vessel Code, Section II, Part A, as opposed to the original ASTM document.

Q: What is the difference between SA312 pipe and SA213 tube?
SA312 covers pipe for pressure and general piping service, sized by nominal pipe size and schedule, while SA213 covers smaller seamless tubes for boilers, superheaters and heat exchangers.

Q: What is the UNS number for TP316L?
TP316L is UNS S31603, equivalent to EN 1.4404 and X2CrNiMo17-12-2.

Q: Can SA312 TP316L be supplied as welded pipe?
Yes. Welded pipe is permitted by the specification, and the purchaser can require radiographic examination, eddy current testing or a hydrostatic test on the finished pipe.

Q: What service temperature is acceptable?
The design code, not the product specification, sets the allowable stress and temperature limits. Allowable stress falls as temperature rises, and many designs add further restrictions in the creep range, so the governing code and the end user specification decide the final limit.