ASTM A269/A269M is a widely used specification for seamless and welded austenitic stainless steel tubing for general service — general corrosion-resisting and low- or high-temperature duty — and is commonly specified for instrumentation, hydraulic and process tubing. This guide summarises the current edition, A269/A269M-24: what it covers, the grades and their chemistry, heat treatment, the tests every lot must pass, dimensional tolerances, and the optional supplementary requirements you can add to an order.
1. Scope: what A269 covers
- Product: seamless or welded austenitic stainless steel tubing of nominal wall thickness, for general corrosion-resisting and low- or high-temperature service.
- Usual size range: ¼ in [6.4 mm] inside diameter and larger, and 0.020 in [0.51 mm] nominal wall and heavier.
- Small sizes: mechanical property requirements do not apply to tubing smaller than ⅛ in [3.2 mm] ID or 0.015 in [0.38 mm] wall. Smaller or thinner tubing is covered by ASTM A632.
- Units: inch-pound units apply unless the order specifies A269M; the two systems are used independently.
- General requirements: tubing must also meet ASTM A1016/A1016M unless A269 says otherwise.
- For tubing used in ASME B31.3 process piping, additional testing may apply.
2. Grades and chemical composition
A269 Table 1 lists more than thirty austenitic grades, from TP201 to super-austenitic alloys such as S31254 and N08904. The six most commonly ordered grades are shown below (percent, maximum unless a range is given).
| Grade | UNS | C | Mn | P | S | Si | Ni | Cr | Mo | Other |
|---|---|---|---|---|---|---|---|---|---|---|
| TP304 | S30400 | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 8.0–11.0 | 18.0–20.0 | – | – |
| TP304L | S30403 | 0.035* | 2.00 | 0.045 | 0.030 | 1.00 | 8.0–12.0 | 18.0–20.0 | – | – |
| TP316 | S31600 | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 10.0–14.0 | 16.0–18.0 | 2.00–3.00 | – |
| TP316L | S31603 | 0.035* | 2.00 | 0.045 | 0.030 | 1.00 | 10.0–15.0 | 16.0–18.0 | 2.00–3.00 | – |
| TP321 | S32100 | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 9.0–12.0 | 17.0–19.0 | – | Ti ≥ 5×(C+N), ≤ 0.70 |
| TP347 | S34700 | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 9.0–12.0 | 17.0–19.0 | – | Nb 10×C min, 1.10 max |
Source: ASTM A269/A269M-24, Table 1. *For small-diameter or thin-wall tubing needing many drawing passes, a carbon maximum of 0.040% is permitted in TP304L, TP304LN, TP316L and TP316LN; small-diameter tubes are those under 0.500 in [12.7 mm] OD and light-wall tubes those under 0.049 in [1.2 mm] minimum wall.
An analysis of one billet, one length of flat-rolled stock or one tube is made from each heat, with product-analysis tolerances from ASTM A480/A480M (not applied to carbon for grades with a carbon maximum of 0.04% or less).
3. Manufacture and heat treatment
- Tubes may be seamless or welded, and hot finished or cold finished at the manufacturer’s option.
- All tubing is supplied solution heat-treated: heated to at least the temperature in Table 2 — 1900 °F [1040 °C] for TP304, 304L, 316, 316L, 321 and 347 — then quenched in water or rapidly cooled. Seamless tubes may instead be quenched directly after hot forming while still above the solution temperature.
- If a lower final heat-treatment temperature is specified, each tube is stencilled with that temperature after the suffix “HT”.
- For TP321, TP347 and TP348, solution annealing above 1950 °F [1065 °C] may impair intergranular corrosion resistance after sensitizing exposure; a lower-temperature stabilization anneal can be specified (Supplementary Requirement S3).
- Tubes are pickled free of scale; pickling is not needed when bright annealing is used.
4. Required tests
| Test | Applies to | Frequency |
|---|---|---|
| Flaring test | Seamless tubes | One end of one tube per lot |
| Flange test | Welded tubes | One end of one tube per lot |
| Reverse flattening test | Welded tubes | One specimen per 1500 ft [460 m] of finished tubing; coils over 1500 ft sampled at both ends |
| Hardness test | All tubes | Two tubes per lot |
| Hydrostatic or nondestructive electric test | All tubes | Every tube; the choice is the manufacturer’s unless the order specifies one |
- Hardness limit: 192 HBW / 200 HV or 90 HRB maximum for TP304, 304L, 316, 316L, 321 and 347 (Table 2). For walls under 0.065 in [1.65 mm], Rockwell superficial or Vickers testing may be used; hardness testing is not required for tubes under ¼ in [6.4 mm] ID or under 0.020 in [0.51 mm] wall.
- No tensile requirement in A269 itself. The specification checks mechanical soundness through hardness, flaring/flange and flattening tests. Tensile and yield values that appear on some mill test certificates are reported by the producer; if your project needs them, state the requirement in the order.
- Coils: a coil must be continuous, without any circumferential butt welds.
- Marking: each tube is marked seamless or welded, with “NDE” when the nondestructive electric test was used, and with the HT temperature when below 1900 °F [1040 °C].
5. Dimensional tolerances (Table 4)
| Group | OD, in [mm] | OD tolerance, in [mm] | Wall tolerance, % | Cut length, over, in [mm] (under: 0) | “Thin-walled” if nominal wall is |
|---|---|---|---|---|---|
| 1 | Up to ½ [13] | ±0.005 [0.13] | ±15 | ⅛ [3.2] | – |
| 2 | ½ to 1½ [13 to 38], excl | ±0.005 [0.13] | ±10 | ⅛ [3.2] | less than 0.065 in [1.65 mm] |
| 3 | 1½ to 3½ [38 to 89], excl | ±0.010 [0.25] | ±10 | ³⁄₁₆ [4.8] | less than 0.095 in [2.41 mm] |
| 4 | 3½ to 5½ [89 to 140], excl | ±0.015 [0.38] | ±10 | ³⁄₁₆ [4.8] | less than 0.150 in [3.81 mm] |
| 5 | 5½ to 8 [140 to 203], excl | ±0.030 [0.76] | ±10 | ³⁄₁₆ [4.8] | less than 0.150 in [3.81 mm] |
| 6 | 8 to 12 [203 to 305], excl | ±0.040 [1.01] | ±10 | ³⁄₁₆ [4.8] | less than 0.200 in [5.08 mm] |
| 7 | 12 to 14 [305 to 356], excl | ±0.050 [1.26] | ±10 | ³⁄₁₆ [4.8] | less than 0.220 in [5.59 mm] |
Source: ASTM A269/A269M-24, Table 4. Wall tolerance widens to ±12.5% when the wall is ¾ in [19.0 mm] or more, or the ID is 60% or less of the OD; tubes under ½ in [12.7 mm] ID that cannot be drawn over a mandrel may vary ±15% in wall. Cut-length tolerances apply up to 24 ft [7.3 m]; beyond that the over-tolerance increases by ⅛ in [3 mm] per 10 ft [3 m] or part thereof, up to ½ in [13 mm].
Ovality of thin-walled tubes: for tubes defined as thin-walled in the last column, the maximum and minimum diameter at any cross section may each deviate from nominal by up to twice the OD tolerance, provided the mean diameter stays within the tolerance.
6. Optional supplementary requirements
These apply only when written into the enquiry or order:
- S1 Stress-relieved annealed tubes — for chloride stress-corrosion service in TP304L, TP316L, TP321, TP347 and TP348: heat treatment at 1550–1650 °F [845–900 °C] after roll straightening, with no mechanical straightening afterwards.
- S2 Pneumatic test — air-under-water or pneumatic leak test per A1016/A1016M.
- S3 Stabilizing heat treatment — for TP321, TP347 and TP348, at a temperature agreed between purchaser and vendor.
- S4 Intergranular corrosion test — per ASTM A262 Practice E.
7. How to order A269 tubing
A269 asks the order to state, as required: quantity (feet, metres or number of lengths); seamless or welded; grade; size as outside diameter and nominal wall thickness; length (specific or random); optional requirements such as heat treatment or the choice of hydrostatic or nondestructive electric test; whether a test report is required; the specification designation (A269 or A269M); and any supplementary requirements.
For example: “500 m, seamless, TP316L, 0.500 in OD × 0.049 in wall, random lengths, hydrostatic test, EN 10204 3.1 certificate, ASTM A269-24, Supplementary Requirement S4.”
How TeCarve supplies A269 tubing
TeCarve is the sole export arm of two stainless steel tube factories in Foshan and Wenzhou, China. We supply A269 tubing in straight lengths and as coiled tubing, along with seamless and welded tube. Every order ships with an EN 10204 3.1 mill test certificate — you can see a real A269 316L certificate in that guide. Trial orders start from 100–300 kg; in-stock sizes ship in 7–10 days and custom production in 10–25 days. Send your grade, OD, wall, length and required tests to sales@tecarve.com.
Frequently asked questions
Is ASTM A269 for seamless or welded tubing?
Both. A269 covers seamless and welded austenitic stainless steel tubing; the order states which is required, and the tube is marked accordingly.
What is the difference between ASTM A269 and A632?
A269 covers tubing usually ¼ in [6.4 mm] ID and larger with walls of 0.020 in [0.51 mm] and heavier. Smaller or thinner tubing is covered by ASTM A632 for small-diameter tubing.
Does every A269 tube get a hydrostatic test?
Every tube gets either a hydrostatic test or a nondestructive electric test. The manufacturer chooses unless the purchase order specifies which one.
What hardness does A269 allow for 316L tubing?
TP316L tubing may not exceed 192 HBW / 200 HV or 90 HRB.
What is the OD tolerance for ½ inch A269 tubing?
A ½ in OD tube falls in Group 2 (½ to 1½ in, excl.): ±0.005 in [0.13 mm] on OD and ±10% on wall.
Related reading: EN 10216-5 guide · ASTM A312 pipe guide · Pipe vs tube · Pipe size & schedule chart · 304 vs 316 vs 316L
