ASTM A312/A312M is the standard specification by ASTM International covering seamless, welded, and heavily cold worked austenitic stainless steel pipe for high-temperature service and general corrosion applications. Dimensions are governed by ASME B36.19M. The companion specification ASME SA-312 adopts identical requirements for ASME Boiler and Pressure Vessel Code (BPVC) compliance.
HT PIPE supplies ASTM A312 / SA-312 compliant seamless and welded stainless steel pipes across all standard grades with full Mill Test Certificates (MTC) per EN 10204 3.1.
ASTM A312/A312M covers austenitic stainless steel pipe in three manufacturing categories:
| Category |
Manufacturing Process |
Size Range (NPS) |
Heat Treatment |
| Seamless Pipe |
Pierced from hollow bloom/billet, hot/cold worked |
NPS 1/8 – NPS 30 |
Solution annealed |
| Welded Pipe |
Formed plate/coil, longitudinal weld (HFW/ERW/SAW) |
NPS 1/8 – NPS 30 |
Solution annealed (entire pipe including weld) |
| Heavily Cold Worked |
Cold worked to enhance strength — no PWHT |
NPS 1/2 – NPS 6 |
No post-weld heat treatment required |
Scope Statement (ASTM A312-24): "This specification covers seamless, welded, and heavily cold worked austenitic stainless steel pipe intended for high-temperature service and for general corrosion applications. Pipe shall be manufactured by the seamless, welded, or heavily cold worked process and shall be heat treated."
| Designation |
Issuing Body |
Unit System |
Dimension Standard |
Latest Edition |
| ASTM A312 |
ASTM International |
Inch-Pound |
ASME B36.19M |
A312/A312M-24 |
| ASTM A312M |
ASTM International |
SI (Metric) |
ASME B36.19M |
A312/A312M-24 |
| ASME SA-312 |
ASME (BPVC Sec. II Part A) |
Both |
ASME B36.19M |
2023 Edition |
2. Grades Covered by ASTM A312
ASTM A312 covers austenitic stainless steel pipe grades (TP = Type) organized into standard and high-performance categories:
2.1 Standard Austenitic Grades (300 Series)
| Grade / TP |
UNS No. |
Alloy Type |
Typical Application |
| TP304 / TP304L / TP304H |
S30400 / S30403 / S30409 |
18Cr-8Ni / Low C / High C |
General chemical, food, dairy, water treatment |
| TP309S / TP309H |
S30908 / S30909 |
22Cr-12Ni heat resisting |
Furnace parts, radiant tubes, heat exchangers |
| TP310S / TP310H |
S31008 / S31009 |
25Cr-20Ni heat resisting |
High-temp furnace, reformer, cracker piping |
| TP316 / TP316L / TP316H |
S31600 / S31603 / S31609 |
16Cr-10Ni-2Mo |
Marine, pharma, chemical process, desalination |
| TP317 / TP317L |
S31700 / S31703 |
18Cr-11Ni-3Mo |
Pulp & paper, FGD, aggressive chemical media |
| TP321 / TP321H |
S32100 / S32109 |
Ti-stabilized |
High-temp piping (>525°C), exhaust, aerospace |
| TP347 / TP347H |
S34700 / S34709 |
Nb+Ta-stabilized |
High-temp pressure vessels, aerospace, nuclear |
| TP348 / TP348H |
S34800 / S34809 |
Ta + Co restricted |
Nuclear reactor coolant circuits |
2.2 Lean & High-Performance Austenitic Grades
| Grade / TP |
UNS No. |
Alloy Type |
Typical Application |
| TPXM-19 (Nitronic 50) |
S20910 |
22Cr-13Ni-5Mn + N |
Cryogenic, high-strength piping, valve stems |
| TPXM-29 |
S24000 |
18Cr-3Ni-12Mn |
High-strength, cryogenic service |
| S31254 (254 SMO type) |
S31254 |
20Cr-18Ni-6Mo (6% Mo) |
Seawater, bleach plant, desalination |
| N08367 |
N08367 |
20Cr-24Ni-6Mo + N |
Offshore platforms, seawater systems |
| N08904 (904L type) |
N08904 |
20Cr-25Ni-4Mo-1.5Cu |
H₂SO₄, phosphoric acid, offshore |
| N08926 |
N08926 |
25Cr-27Ni-3Mo-1.5Cu + N |
High-chloride seawater, sour gas |
3. Chemical Composition — Key Grades (ASTM A312 Table 1)
Values are maximum unless shown as a range. "—" = not required / not applicable. Heat analysis per ASTM A312-24.
| Grade |
C% |
Mn% |
P% |
S% |
Si% |
Cr% |
Ni% |
Mo% |
N% |
Other |
| TP304 |
0.08 |
2.00 |
0.045 |
0.030 |
0.75 |
18.0–20.0 |
8.0–11.0 |
— |
— |
— |
| TP304L |
0.035 |
2.00 |
0.045 |
0.030 |
0.75 |
18.0–20.0 |
8.0–12.0 |
— |
— |
— |
| TP304H |
0.04–0.10 |
2.00 |
0.045 |
0.030 |
0.75 |
18.0–20.0 |
8.0–11.0 |
— |
— |
— |
| TP316 |
0.08 |
2.00 |
0.045 |
0.030 |
0.75 |
16.0–18.0 |
11.0–14.0 |
2.0–3.0 |
— |
— |
| TP316L |
0.035 |
2.00 |
0.045 |
0.030 |
0.75 |
16.0–18.0 |
10.0–14.0 |
2.0–3.0 |
— |
— |
| TP316H |
0.04–0.10 |
2.00 |
0.045 |
0.030 |
0.75 |
16.0–18.0 |
11.0–14.0 |
2.0–3.0 |
— |
— |
| TP321 |
0.08 |
2.00 |
0.045 |
0.030 |
0.75 |
17.0–19.0 |
9.0–12.0 |
— |
— |
Ti: 5×C–0.70 |
| TP347 |
0.08 |
2.00 |
0.045 |
0.030 |
0.75 |
17.0–19.0 |
9.0–13.0 |
— |
— |
Nb+Ta: 10×C–1.0 |
| TP310S |
0.08 |
2.00 |
0.045 |
0.030 |
1.50 |
24.0–26.0 |
19.0–22.0 |
— |
— |
— |
| S31254 |
0.020 |
1.00 |
0.030 |
0.010 |
0.80 |
19.5–20.5 |
17.5–18.5 |
6.0–7.0 |
0.18–0.25 |
Cu: 0.50–1.0 |
| N08904 |
0.020 |
2.00 |
0.040 |
0.030 |
1.00 |
19.0–23.0 |
23.0–28.0 |
4.0–5.0 |
— |
Cu: 1.0–2.0 |
| N08367 |
0.030 |
2.00 |
0.040 |
0.030 |
1.00 |
20.0–22.0 |
23.5–25.5 |
6.0–7.0 |
0.18–0.25 |
— |
| TPXM-19 |
0.06 |
4.0–6.0 |
0.045 |
0.030 |
1.00 |
20.5–23.5 |
11.5–13.5 |
1.50–3.00 |
0.20–0.40 |
V: 0.10–0.30 |
Note: Full chemistry ranges and additional grades per ASTM A312-24 Table 1. Product analysis tolerances apply.
4. Mechanical Property Requirements (ASTM A312 Table 2)
All values are minimum requirements in the solution-annealed condition. Per ASTM A312/A312M-24.
| Grade |
UNS |
Tensile Strength
min MPa (ksi) |
Yield Strength 0.2%
min MPa (ksi) |
Elong.
min % |
Hardness
max |
| TP304 |
S30400 |
515 (75) |
205 (30) |
35 |
92 HRB / 192 HBW |
| TP304L |
S30403 |
485 (70) |
170 (25) |
35 |
92 HRB / 192 HBW |
| TP304H |
S30409 |
515 (75) |
205 (30) |
35 |
92 HRB / 192 HBW |
| TP316 |
S31600 |
515 (75) |
205 (30) |
35 |
95 HRB / 217 HBW |
| TP316L |
S31603 |
485 (70) |
170 (25) |
35 |
95 HRB / 217 HBW |
| TP316H |
S31609 |
515 (75) |
205 (30) |
35 |
95 HRB / 217 HBW |
| TP321 |
S32100 |
515 (75) |
205 (30) |
35 |
95 HRB / 217 HBW |
| TP347 |
S34700 |
515 (75) |
205 (30) |
35 |
95 HRB / 217 HBW |
| TP310S |
S31008 |
515 (75) |
205 (30) |
35 |
95 HRB / 217 HBW |
| S31254 |
S31254 |
655 (95) |
310 (45) |
35 |
90 HRB / 195 HBW |
| N08904 |
N08904 |
490 (71) |
215 (31) |
35 |
90 HRB / 200 HBW |
| N08367 |
N08367 |
550 (80) |
240 (35) |
35 |
90 HRB / 200 HBW |
| TPXM-19 |
S20910 |
620 (90) |
345 (50) |
35 |
100 HRB / 241 HBW |
Note: For heavily cold worked pipe, yield and tensile strength may be substantially higher. Test requirements per ASTM A370.
5. Heat Treatment Requirements
| Grade Family |
Condition |
Heat Treatment |
Cooling |
| Standard Austenitic (TP304, TP316…) |
Solution Annealed |
1040–1100°C (1900–2010°F) min |
Rapid quench — water or air |
| Stabilized (TP321, TP347, TP348) |
Solution Annealed |
1040–1100°C (1900–2010°F) min |
Rapid quench — water or air |
| Heat-Resisting (TP309, TP310) |
Solution Annealed |
1040–1100°C (1900–2010°F) min |
Water quench preferred |
| High-Performance (S31254, N08367…) |
Solution Annealed |
1100–1150°C (2010–2100°F) |
Water quench required |
| Heavily Cold Worked Pipe |
Cold Worked |
Cold work to enhance strength; no PWHT |
N/A — no heat treatment |
Important: Welded A312 pipe must be solution annealed after welding — the entire pipe including the weld zone must reach solution annealing temperature and be rapidly cooled. This is critical for H grades and stabilized grades to ensure carbides are dissolved and the weld HAZ is fully annealed.
6. Testing & Inspection Requirements
| Test |
Requirement |
Reference Standard |
| Chemical Analysis (Heat) |
One per heat / melt; all elements per Table 1 |
ASTM A312 Table 1 |
| Tensile Test (Transverse) |
One per lot (pipe lengths from same heat/heat treat lot) |
ASTM A370 |
| Flattening Test |
Welded pipe: one per 100 lengths from same lot; seamless exempt |
ASTM A312 |
| Flange Test (optional) |
Alternative to flattening for welded pipe |
ASTM A312 |
| Hardness Test |
Brinell or Rockwell; one per lot |
ASTM E10 / E18 |
| Intergranular Corrosion (IGC) |
Supplementary S2 for L-grades; practice per A262 |
ASTM A262 Practice A, B, or E |
| Hydrostatic Test |
Each pipe: hold for 5 sec at calculated test pressure = 2S×t/D (max 2500 psi) |
ASTM A312 |
| Non-Destructive Test (NDT) |
Alternative to hydrostatic: ERW/HFW pipe — eddy current or ultrasonic perASTM A888 |
ASTM A888 / E213 / E309 |
7. Pipe Dimensions — ASME B36.19M (Stainless Steel Pipe)
ASTM A312 pipe dimensions are per ASME B36.19M (Stainless Steel). Key schedule thicknesses for common NPS:
| NPS |
OD
(mm) |
Sch 5S
mm |
Sch 10S
mm |
Sch 40S
mm |
Sch 80S
mm |
Sch 160
mm |
XXS
mm |
| 1/2 |
21.34 |
1.65 |
2.11 |
2.77 |
3.73 |
4.78 |
7.47 |
| 1 |
33.43 |
1.65 |
2.77 |
3.38 |
4.55 |
5.16 |
9.09 |
| 2 |
60.33 |
1.65 |
2.77 |
2.77 |
3.91 |
6.55 |
11.07 |
| 4 |
114.30 |
2.11 |
3.05 |
3.05 |
4.85 |
7.14 |
— |
| 6 |
168.28 |
2.11 |
3.40 |
3.40 |
5.16 |
7.11 |
— |
| 8 |
219.08 |
2.11 |
3.76 |
3.76 |
5.16 |
8.18 |
— |
| 10 |
273.05 |
2.11 |
3.96 |
4.19 |
5.16 |
9.27 |
— |
| 12 |
323.85 |
2.77 |
4.57 |
4.57 |
5.16 |
9.53 |
— |
Note: NPS 14 and above: 40S wall = 6.35 mm. Sch 5S/10S are thin-wall schedules unique to B36.19M. Full B36.19M table covers NPS 1/8 to NPS 30. Carbon steel pipe per B36.10M uses different schedules.
8. Industries & Applications
| Industry |
Recommended Grades |
Typical Pipe Sizes & Schedules |
| Chemical & Petrochemical |
TP304L, TP316L, TP904L |
NPS 1/2 – NPS 24; Sch 10S–80S |
| Oil & Gas / Offshore |
TP316L, TP316H, S31254, N08367 |
NPS 2 – NPS 20; Sch 10S–80S |
| Desalination / Seawater |
S31254, N08367, N08926 |
NPS 4 – NPS 16; Sch 10S–40S |
| Power Generation |
TP321H, TP347H, TP310S |
NPS 1 – NPS 24; Sch 40S–160 |
| Pharma / Food & Beverage |
TP304L, TP316L |
NPS 1/2 – NPS 8; Sch 5S–10S |
| Paper & Pulp (FGD) |
TP317L, TP904L, N08367 |
NPS 4 – NPS 24; Sch 10S–40S |
9. A312 vs A358 vs A778 — Stainless Pipe Specifications Compared
| Criteria |
ASTM A312 |
ASTM A358 |
ASTM A778 |
| Pipe Type |
Seamless + Welded |
Welded (HFW/SAW) |
Welded only |
| Heat Treatment |
Solution annealed (all pipe) |
Solution annealed (all pipe) |
Not required (un-annealed) |
| NDE of Weld |
Optional / per purchase order |
Mandatory (radiographic, UT, or ET) |
Optional |
| Grades |
Austenitic TP grades |
Same as A312 (augmented) |
TP304, TP304L, TP316L only |
| Application |
General corrosion + high-temp |
Critical / code-grade welded pipe |
Low-pressure restrained piping |
| Cost |
Moderate |
Higher (NDE required) |
Lower (no heat treatment) |
Key Distinction: ASTM A312 is the most commonly used stainless steel pipe specification for general industrial service. A358 adds mandatory weld NDE for critical service. A778 is for low-pressure applications where post-weld annealing is not required and some sensitization is acceptable.
10. Related Standards
| Standard |
Scope |
Relationship to A312 |
| ASME B36.19M |
Stainless Steel Pipe — OD, Wall, Weight |
Mandatory dimension standard for A312 |
| ASME B36.10M |
Welded & Seamless Wrought Steel Pipe (carbon) |
Carbon steel pipe dimensions (different schedules) |
| ASTM A370 |
Mechanical Testing of Steel Products |
Tensile test method required by A312 |
| ASTM A262 |
Intergranular Corrosion Test |
Supplementary requirement for L-grades |
| ASTM A358 |
Welded Pipe — Aug. Quality (NDE required) |
Higher-quality welded pipe alternative |
| ASTM A778 |
Welded Unannealed Austenitic SS Pipe |
Lower-cost alternative for limited service |
| ASME B31.3 |
Process Piping Code |
Governs allowable stress, design of A312 piping |
11. How to Order — Required Information
| No. |
Item |
Requirement / Example |
| 1 |
Specification |
ASTM A312 / ASME SA-312 |
| 2 |
Grade / UNS |
e.g., TP316L (UNS S31603) or TP321H (UNS S32109) |
| 3 |
Manufacturing Process |
Seamless (SML) or Welded (WLD) |
| 4 |
NPS & Schedule |
e.g., NPS 4 Sch 10S or NPS 6 Sch 40S |
| 5 |
Length |
Random (RL), Single Random (SRL ~6m), Double Random (DRL ~12m), or Cut-to-length |
| 6 |
Ends |
Plain End (PE), Beveled End (BE), Threaded (T&C) — per ASME B1.20.1 |
| 7 |
Supplementary Tests |
A262 IGC (for L-grades), flattening test, PMI, UT, Hydro |
| 8 |
Certification |
EN 10204 3.1 Certified Mill Test Report |
| 9 |
Quantity |
Lineal meters or tons (MT) |
Download ASTM A312 / A312M Standard (PDF)
The official ASTM A312/A312M-24 PDF is available from our HT Pipe Download Center. The document includes full chemical composition Table 1, mechanical property Table 2, heat treatment requirements, dimensions per ASME B36.19M, and supplementary requirements.
Go to Download Center | Request MTC / Quotation
12. Frequently Asked Questions
Q: What is ASTM A312 stainless steel pipe?
ASTM A312/A312M is the standard specification for seamless, welded, and heavily cold worked austenitic stainless steel pipe. It covers pipe for general corrosion and high-temperature service in sizes NPS 1/8 to NPS 30, with dimensions per ASME B36.19M. Common grades include TP304, TP304L, TP316, TP316L, TP321, TP347, and TP310S.
Q: Seamless vs Welded A312 pipe — which to choose?
Seamless A312 pipe has no weld seam and is preferred for high-pressure, high-temperature, or critical service applications. Welded A312 pipe (HFW or SAWL) is more cost-effective for moderate-pressure applications and is acceptable for most chemical and process piping per ASME B31.3. Both must be fully solution annealed and pass the same mechanical tests.
Q: What are the mechanical properties of ASTM A312 TP316L?
ASTM A312 TP316L (UNS S31603): minimum tensile strength 485 MPa (70 ksi), yield strength 0.2% offset min. 170 MPa (25 ksi), elongation min. 35% in 2 inches, hardness max. 95 HRB / 217 HBW. Must be solution annealed at 1040–1100°C and rapidly cooled.
Q: What is Sch 10S vs Sch 40S stainless steel pipe?
Sch 10S and Sch 40S are stainless steel pipe schedules per ASME B36.19M. Sch 10S is a thin-wall schedule (~2.77 mm for NPS 2), while Sch 40S (≈STD) has heavier walls (~3.91 mm for NPS 2). Note: carbon steel B36.10M schedules differ — Sch 10 (carbon) has the same OD but different wall thickness than Sch 10S (stainless). Always reference B36.19M for stainless pipe.
Q: Can ASTM A312 pipe be used in ASME B31.3 process piping?
Yes. ASTM A312 seamless or welded austenitic stainless steel pipe is fully acceptable for ASME B31.3 Process Piping. Material specification for Chapter II (Design) and Chapter VI (Materials) must reference ASTM A312 or ASME SA-312. Allowable stress values (S) for each grade are listed in B31.3 Table K-1.
Q: Is A312 the same as ASME SA-312?
Technically identical in chemistry and mechanical properties. ASME SA-312 is ASTM A312 adopted into ASME BPVC Section II Part A. SA-312 additionally requires Certified Material Test Reports (CMTR) with full traceability and authorized inspection for ASME Code-stamped piping systems. Most mills supply dual-certified A312/SA-312 material at no additional cost.
Request a Quote — ASTM A312 Seamless & Welded Stainless Steel Pipe
Zhengzhou Huitong (HT Pipe) supplies ASTM A312 / SA-312 compliant seamless and welded stainless steel pipes in all standard grades. Full EN 10204 3.1 CMTRs and competitive lead times from affiliated mills in China.
