ASTM and ASME specifications

ASTM A312 / ASME SA-312 Stainless Steel Pipe

Compare A312 pipe grades, seamless and welded routes, and dimensions. Send your specified edition, size, schedule and quantity for a quote.

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Technical reference

Specifications and ordering data

Specification

Field	Order reference
Standard	ASTM A312/A312M or ASME SA-312 as ordered
Product or route	Seamless, welded and heavily cold-worked austenitic pipe within the standard
Critical dimensions and fit	Order NPS, schedule or specified wall, exact TP or UNS grade, route and ends
Supply enquiry	Confirm sizes, lengths, route, documentation and lead time for your order

Dimensions and weight

Selected ASME B36.19 dimensions. Schedule columns give nominal wall thickness. Theoretical inside diameter and mass use nominal dimensions, with a reference density of 8,000 kg/m³. Actual mass varies by grade and tolerances.

NPS	OD (mm)	10S wall (mm)	40S wall (mm)	80S wall (mm)	40S ID (mm)	40S kg/m
½	21.34	2.11	2.77	3.73	15.80	1.29
¾	26.67	2.11	2.87	3.91	20.93	1.72
1	33.40	2.77	3.38	4.55	26.64	2.55
1½	48.26	2.77	3.68	5.08	40.90	4.12
2	60.33	2.77	3.91	5.54	52.51	5.54
2½	73.03	3.05	5.16	7.01	62.71	8.80
3	88.90	3.05	5.49	7.62	77.92	11.51
4	114.30	3.05	6.02	8.56	102.26	16.38
5	141.30	3.40	6.55	9.52	128.20	22.18
6	168.28	3.40	7.11	10.97	154.06	28.80
8	219.08	3.76	8.18	12.70	202.72	43.36
10	273.05	4.19	9.27	12.70	254.51	61.46
12	323.85	4.57	9.52	12.70	304.81	75.21

Reference ASME B36.19 dimensional standard · Tonkin stainless pipe dimensional chart

Service and pressure basis

Use the approved design code and service conditions. The applicable rating depends on material, temperature, minimum effective wall, joint details and the limits of the connected assembly. A schedule or a hydrostatic test result alone cannot establish an operating pressure.

Reference ASME process piping code B31.3

Chemical composition

Selected chemistry by mass for the A312 pipe designations below. The ordered edition, full element limits and any applicable notes govern acceptance. A dash means the value is omitted here.

Grade	UNS	C (%)	Cr (%)	Mo (%)	Grade feature
TP304	S30400	≤0.08	18–20	—	Chromium-nickel base grade
TP316	S31600	≤0.08	16–18	2–3	Molybdenum-bearing grade
TP321	S32100	≤0.08	17–19	—	Titanium stabilised
TP347	S34700	≤0.08	17–19	—	Niobium stabilised
TP304L	S30403	≤0.035	18–20	—	Low carbon
TP304H	S30409	0.04–0.10	18–20	—	Controlled carbon range
TP316L	S31603	≤0.035	16–18	2–3	Low carbon
TP316H	S31609	0.04–0.10	16–18	2–3	Controlled carbon range
TP310S	S31008	≤0.08	24–26	—	High chromium and nickel
TP317L	S31703	≤0.035	18–20	3–4	Higher molybdenum range than TP316L
TP316Ti	S31635	≤0.08	16–18	2–3	Titanium stabilised
TP321H	S32109	0.04–0.10	17–19	—	Titanium stabilised
TP347H	S34709	0.04–0.10	17–19	—	Niobium stabilised
904L	N08904	≤0.02	19–23	4–5	Copper-bearing high-alloy grade

Reference ASTM A312/A312M scope · Centravis tubular product catalogue · Alleima high-temperature tubular grades

Mechanical properties

Selected minimum room-temperature tensile and yield strengths for A312 pipe. Elongation acceptance depends on the specimen orientation and applicable thickness basis. For tube orders, apply the nominated tube specification.

Grade	Tensile minimum (MPa)	Yield minimum (MPa)
TP304	515	205
TP316	515	205
TP321	515	205
TP347	515	205
TP304L	485	170
TP304H	515	205
TP316L	485	170
TP316H	515	205
TP310S	515	205
TP317L	515	205
TP316Ti	515	205
TP321H	515	205
TP347H	515	205
904L	490	215

Reference ASTM A312/A312M scope · CTS A312 technical reference · Tioga A312 pipe grade reference

Testing and certificates

Request the heat record, material results and applicable nondestructive electric or hydrostatic test evidence.

When	What to check
Before ordering	Document the required test method, edition and any witness points
At delivery	Match the material report and heat or lot identification to the shipment

Application and product comparison

A269 is general-service tubing sized by actual OD and wall.

For the enquiry, order NPS, schedule or specified wall, exact TP or UNS grade, route and ends.

Example request for quotation

ASTM A312/A312M or ASME SA-312 as ordered · TP316L NPS 2 Sch 40S seamless, 12 lengths × 6 m, bevel per drawing. Add quantity, lengths, delivery city and the required reports.

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Ordering guidance

Separate the material standard from the dimensional standard

ASTM A312 covers specified austenitic stainless steel pipe products. ASME B36.19 provides dimensional references for stainless pipe. Quote the required material grade and product specification alongside NPS and schedule, rather than treating the schedule as a material specification.

State the required manufacturing route and any supplementary test or traceability requirement. If the order calls for ASME SA-312, repeat that exact designation and edition on the purchase line and request confirmation on the documents.

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Illustration: Three round pipe and tube cross-sections

Material callouts

How to specify the A312 grade

The purchase line needs the TP grade, not just “A312 stainless steel.” Use the grade in the material specification and confirm availability for the required size and route.

Common callout	What to check on the offer
TP304 / TP304L	Quote the exact 304 or 304L requirement. Confirm dual marking on the certificate if offered.
TP316 / TP316L	Quote the exact 316-family grade and the required pipe route. A dimensional match does not establish grade compliance.

See the 316L page for a pipe OD and schedule reference. Dimensions are not a stock or pressure-rating table.

Buyer’s guide

A312 and SA-312 purchase checks before releasing pipe

Read the three parts of the callout

A312 or SA-312 names the material specification, TP304L or TP316L identifies the grade, and the specified dimensional reference controls the pipe dimensions. ASME B36.19 is commonly used for stainless pipe dimensions where called out. Record the NPS and the full schedule designation, including any suffix on the drawing. Confirm actual OD and wall when a spool has to match installed piping.

Record the permitted manufacturing route

A312 covers seamless, welded and heavily cold-worked austenitic pipe within its scope. If an order permits only one route, put that restriction on the RFQ. Where the supplier offers a different route, request a separate technical deviation and check the offer against the applicable product and project requirements before release.

Compare the certificate and inspection scope

Ask the quotation to identify the ASTM or ASME edition, heat traceability, applicable test records, length basis and end condition. For an ASME code job, use the Section II material designation and edition required by the project and ask that the documentation match. Obtain agreement before cutting or transferring markings between lengths.

Purchase field	What it controls	What to record
Material specification	Product form, routes and acceptance requirements within scope	A312 or SA-312 and specified edition
Grade	The material required within the specification	Full designation such as TP316L
Dimensional basis	Pipe outside diameter and wall series	NPS, full schedule and applicable dimensional standard
Project additions	Requirements beyond the basic item description	Route restriction, length, ends and inspection scope

Example enquiry

An illustrative quote line is A312 TP316L, NPS 2, Schedule 40S, seamless where required, with lengths and ends per isometric and traceability per the purchase order. Give any ASME code requirement separately and explicitly.

Does the pipe schedule establish working pressure?

It identifies a wall series. Use the project design code, material, temperature and system details to determine the allowable service conditions.

Technical references ASTM A312/A312M scope · ASME B36.19 pipe dimensions · ASME Boiler and Pressure Vessel Code, Section II

Prepare your enquiry

What to put on the purchase list

Item	What to send
Product details	A312 or SA-312 as specified · TP grade · NPS · schedule · route · documentation
Delivery	Quantity with units, delivery city and required date if known
Acceptance	Required certificates and inspection scope; attach the drawing revision where applicable

Does A312 identify the wall thickness?

No. Include the schedule or specified wall, plus nominal size.

Technical reference: ASTM steel standards catalogue

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Send your dimensions, quantities and delivery city. Include any inspection or material certificate requirements so they can be quoted against the same line items.

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