ASTM A479 / A479M: Stainless Steel Bars & Shapes for Pressure Vessels
Crestflo machines instrumentation valve bodies, fitting bodies, manifold bodies and bar-stock thermowells from A479-conforming bar, and every part ships with an EN 10204 3.1 material test certificate and a heat number. Turnaround runs 6–8 weeks.
ASTM A479 / A479M carries the title "Standard Specification for Stainless Steel Bars and Shapes for Use in Boilers and Other Pressure Vessels." ASTM International publishes it, and the ASME Boiler & Pressure Vessel Code has adopted it as SA-479. The spec covers hot- and cold-finished bar and shapes across four families: austenitic, duplex, ferritic and martensitic stainless.
Scope note: ASTM A479 is a bar-and-shapes product-form specification, not a tube spec (ASTM A213 / A269), not a forging spec (ASTM A182), and stricter than the general bar spec ASTM A276. This page defines the standard; Crestflo does not sell raw bar or mill product, it supplies finished instrumentation components machined from A479-conforming bar.
Request an ASTM A479 quote → · sales@crestflousa.com · +1 346 594 9005
Also known as: ASTM A479 designations & related terms
Buyers and specifications write this standard many ways. The names below all point back to the same specification and the same grades.
| Category | Terms covered |
|---|---|
| Primary designation | ASTM A479, A479, ASTM-A479, ASTM International A479 |
| Metric companion | ASTM A479/A479M, A479M, A 479, A479/A479M (M = SI / metric units) |
| ASME adoption | ASME SA-479, SA479, SA-479 (Boiler & Pressure Vessel Code, Section II Part A) |
| Full title | "Standard Specification for Stainless Steel Bars and Shapes for Use in Boilers and Other Pressure Vessels" |
| Grade-form call-outs | A479 Type 304, A479 316, A479 316L, A479 F304, A479 F316, A479 XM-19, A479 UNS S31600, A479 duplex, A479 S32750 |
| Common phrasings | A479 spec, A479 standard, A479 specification, A479 stainless bar, A479 bar spec, stainless steel bars ASTM A479, A479 supplier, A479 manufacturer USA |
Standard at a glance: ASTM A479 attributes
| Attribute | Value (standard published reference) |
|---|---|
| Designation | ASTM A479 / A479M (the M companion gives SI / metric units) |
| Full title | "Standard Specification for Stainless Steel Bars and Shapes for Use in Boilers and Other Pressure Vessels" |
| Issuing body | ASTM International |
| ASME adoption | Adopted into the ASME Boiler & Pressure Vessel Code as SA-479 (BPVC Section II, Part A) |
| Current edition | ASTM revises A479 periodically; cite the current published edition your project specification requires |
| Scope | Hot-finished and cold-finished stainless bars (rounds, squares, hexagons) and hot-rolled or extruded shapes (angles, tees, channels) for boilers and other pressure vessels |
| Grade families | Austenitic, austenitic-ferritic (duplex), ferritic and martensitic stainless steels |
| Grade identification | By UNS number plus type designation (e.g. Type 316 = UNS S31600) |
| Heat-treatment condition | Solution-annealed for austenitic and duplex grades; condition varies by grade family |
| Required testing | Tension test, hardness test, chemical analysis (heat and product), and product marking per the standard |
| Related product-form specs | A276 (general bar), A182 (forgings/flanges), A213/A269 (tube), A312 (pipe), A789/A790 (duplex tube) |
The standard's full grade table and numeric acceptance tables are copyrighted and set by the current edition, so this page summarizes scope, grades and representative requirements rather than reproducing the document itself. Values are per the applicable standard. Customizable to requirement.
What is ASTM A479?
ASTM A479 / A479M is the ASTM International standard specification covering hot- and cold-finished stainless steel bars and shapes used in boilers and other pressure vessels. Its full title reads "Standard Specification for Stainless Steel Bars and Shapes for Use in Boilers and Other Pressure Vessels." The "/A479M" companion designation spells out the same requirements in SI (metric) units. A479 and A479M aren't two separate standards, then, just two unit systems built on one specification.
A479 lays out which stainless grades are acceptable, the chemical and mechanical requirements, heat-treatment conditions, and how the bar has to be tested and marked for pressure-retaining service. That service is safety-critical, so ASTM International's requirements got pulled into the ASME Boiler & Pressure Vessel Code as SA-479. A bar ordered to A479, then, is the same material a boiler or vessel fabricator would call out as SA-479.
ASTM A479 scope: bars and shapes for pressure vessels
The specification covers two product families, available in both hot-finished and cold-finished conditions:
- Bars, round, square and hexagon.
- Shapes, hot-rolled or extruded angles, tees and channels.
Both cover boilers and other pressure vessels, and that's the line separating A479 from the broader stainless bar spec, ASTM A276. A276 handles general engineering bar and shapes. A479 is narrower: it's the pressure-vessel-qualified subset the ASME code recognizes as SA-479.
Where can I get the ASTM A479 PDF?
The full standard is copyrighted and sold by ASTM International through its official webstore. This page summarizes A479's scope, grades and requirements for engineering reference but does not reproduce or distribute the copyrighted document. For compliance work, purchase the current official edition rather than relying on unofficial "free download" copies, which may be superseded.
ASTM A479 grades covered: types & UNS numbers
Crestflo teaches on every grade in A479, which covers austenitic, duplex, ferritic and martensitic stainless steels, each tagged with a UNS number and type. The grades customers ask for most are listed below. Crestflo never sells bar or mill product for any of them; it supplies each one only as an instrumentation form, whether that's a valve, a fitting, a manifold or a thermowell.
| Grade / Type | UNS No. | Family | Material reference |
|---|---|---|---|
| 304 | S30400 | Austenitic | 304 / 304L |
| 304L | S30403 | Austenitic (low-carbon) | 304 / 304L |
| 316 | S31600 | Austenitic (Mo-bearing) | 316 / 316L |
| 316L | S31603 | Austenitic (low-carbon) | 316 / 316L |
| 321 / 347 | S32100 / S34700 | Austenitic (stabilized) | — |
| 309 / 310 | S30900 / S31000 | Austenitic (heat-resistant) | — |
| XM-19 (Nitronic 50) | S20910 | High-strength austenitic | — |
| 904L | N08904 | Super-austenitic | 904L |
| Duplex 2205 | S31803 / S32205 | Austenitic-ferritic (duplex) | Duplex 2205 |
| Super Duplex 2507 | S32750 | Super-duplex | Super Duplex 2507 |
| Super Duplex | S32760 | Super-duplex | Super Duplex 2507 |
| Ferralium 255 | S32550 | Super-duplex | Super Duplex 2507 |
| 410 / 430 | S41000 / S43000 | Martensitic / ferritic | — |
The full list of grades sits in the current edition of the standard, so always check any specific grade against that edition. Values follow the applicable standard and can be adjusted to requirement.
ASTM A479 Grade 304 & 316 (the common austenitic grades)
Type 304 (UNS S30400) under A479 is the standard 18Cr-8Ni austenitic bar grade, chosen for general corrosion resistance. 304L (S30403) is the low-carbon version, and it resists sensitization when welded. Molybdenum gets added in Type 316 (S31600), which improves resistance to pitting. 316L (S31603) is the low-carbon form of that grade, and it's the one most often specified for instrumentation exposed to aggressive media. Composition, properties and grade selection are covered on the 316 / 316L material page and the 304 / 304L material page.
ASTM A479 duplex & super-duplex (2205, 2507)
A479 also covers austenitic-ferritic duplex grades, including 2205 (UNS S31803 / S32205) and super-duplex 2507 (S32750), S32760 and S32550. These deliver higher strength and chloride-cracking resistance than standard austenitics, see Duplex 2205 and Super Duplex 2507, and the 2205 vs 2507 comparison.
ASTM A479 chemical composition (representative grades)
Composition depends on each grade's chemistry, and A479 sets those specs. Below are typical nominal ranges, in weight percent, for the common grades.
| Grade (UNS) | C max | Cr | Ni | Mo | N |
|---|---|---|---|---|---|
| 304L (S30403) | 0.030 | 18.0–20.0 | 8.0–12.0 | — | — |
| 316L (S31603) | 0.030 | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | — |
| 2205 (S31803 / S32205) | 0.030 | 22.0–23.0 | 4.5–6.5 | 3.0–3.5 | 0.14–0.20 |
| 2507 (S32750) | 0.030 | 24.0–26.0 | 6.0–8.0 | 3.0–5.0 | 0.24–0.32 |
Values match the applicable grade chemistry and the current A479 edition, and can be tailored to your requirements. The standard sets the full per-grade limits, including Mn, Si, P and S.
ASTM A479 mechanical properties (representative annealed minima)
A479 lays out minimum tensile and yield strength, elongation and hardness limits, broken down by grade, size and finish. Here are representative minima for solution-annealed bar in the common grades:
| Grade | Tensile min | Yield min (0.2% offset) | Elongation min | Hardness max |
|---|---|---|---|---|
| 304L | 70 ksi (485 MPa) | 25 ksi (170 MPa) | 40% | ~92 HRB |
| 316L | 70 ksi (485 MPa) | 25 ksi (170 MPa) | 40% | ~95 HRB |
| 2205 | 95 ksi (655 MPa) | 65 ksi (450 MPa) | 25% | 31 HRC |
| 2507 | 116 ksi (800 MPa) | 80 ksi (550 MPa) | 15% | 32 HRC |
Minima shift with grade, section size and finish, and they're set by the current A479 edition. Values follow whichever standard applies, and can be customized to requirement. Confirm the governing minima against the edition your specification cites.
ASTM A479 vs ASME SA-479: are they the same?
SA-479 is the ASME Boiler & Pressure Vessel Code's adoption of ASTM A479. ASME reviews ASTM specifications and republishes the accepted ones with an "SA" prefix in Section II, Part A. A479 and SA-479 are technically equivalent. Which designation you cite depends on the code of construction: a bar ordered to A479 satisfies an SA-479 call-out as long as its edition and requirements match. For pressure-vessel and boiler work under the ASME code, though, the specification is usually cited as SA-479.
ASTM A479 vs A276 vs A182: which stainless spec applies?
The three specs differ in product form and pressure-vessel qualification, not grade. The same UNS chemistry can show up in all three.
| Specification | Product form | Pressure-vessel qualified? | Typical role |
|---|---|---|---|
| ASTM A479 | Bars & shapes (rounds, squares, hexagons, angles, tees, channels) | Yes, adopted as ASME SA-479 | Bar stock for pressure-retaining components; the material Crestflo machines |
| ASTM A276 | Bars & shapes (general) | No (general engineering bar) | General stainless bar; A479 is the stricter, code-adopted subset |
| ASTM A182 | Forgings, flanges, forged fittings (F-grades) | Yes (forged product form) | Forged pressure parts, e.g. F316 forged fittings, a different product form |
A479 covers pressure-vessel-qualified bar and shapes. A276 covers general bar and shapes. A182 covers forgings and flanges. Match by UNS number first, then by whatever product form your design calls for. There's no single "equivalent" to A479, equivalence runs on grade (the same UNS chemistry in a different form) and on code (SA-479).
Related standards & product forms
A479 belongs to a family of stainless product-form specifications. Picking the right one starts with the product form your part actually needs.
| Standard | Product form | Reference page |
|---|---|---|
| ASTM A479 | Bars & shapes for pressure vessels | This page |
| ASTM A276 | General stainless bars & shapes | ASTM A276 |
| ASTM A182 | Forgings, flanges, forged fittings | ASTM A182 |
| ASTM A213 | Seamless ferritic/austenitic boiler & heat-exchanger tube | ASTM A213 |
| ASTM A269 | Seamless & welded austenitic instrumentation tubing | ASTM A269 |
| ASTM A312 | Seamless & welded austenitic pipe | ASTM A312 |
| ASTM A789 / A790 | Seamless & welded duplex tube / pipe | ASTM A789 · ASTM A790 |
For sour service, A479 grade selection is often layered with NACE MR0175 / ISO 15156 requirements. Check the sour-service selection guide for details.
ASTM A479 testing, traceability & NACE conformance
Crestflo's mill work under A479 covers tension and hardness testing, chemical analysis on both heat and product, and product marking. Beyond what the standard itself calls for, Crestflo layers on the documentation and verification a QA reviewer or spec checker needs before signing off on a delivered part.
| Requirement | How Crestflo satisfies it |
|---|---|
| Grade verification | PMI (positive material identification) on the delivered component, in addition to the mill's heat and product analysis |
| Mechanical / condition proof | Solution-annealed condition per grade; tensile and hardness reportable to requirement |
| Documentation / traceability | EN 10204 3.1 material test certificate as standard (3.2 on request), with a heat/lot number on every part |
| Independent verification | In-house NDT; destructive testing at ISO/IEC 17025-accredited labs; third-party inspection on request |
| Sour-service overlay | Where the service is sour, grades supplied to NACE MR0175 / ISO 15156 requirements, with the qualified condition documented |
Full EN 10204 MTC mechanics and our country-of-origin & TAA position are documented on their own pages. Datasheets and CAD models are available to customers on request.
Crestflo instrumentation parts machined from A479-conforming bar
Crestflo doesn't sell A479 bar as raw stock. Instead, it machines finished instrumentation components from A479-conforming stainless and duplex bar, so the pressure-boundary material carries the A479/SA-479 pedigree while the part ships ready to install.
- Instrumentation valve bodies, needle, ball, check/NRV and bleed valves, bar-stock and forged-body, qualified to the applicable valve standards ASME B16.34 / API (not the compression-fitting standard).
- Manifold bodies, 2-valve, 3-valve and 5-valve, with 100% seat and shell leak testing.
- Compression tube fitting bodies, machined from A479-conforming bar and tested for interchange per ASTM F1387, in imperial and metric sizes up to 2" (50 mm) OD.
- Bar-stock thermowells, flanged and threaded, machined from solid A479 bar, up to 1 m length.
Grades in the A479 families above are available across these forms, from 316/316L and 904L to Duplex 2205 and Super Duplex 2507, supplied only as instrumentation components, not bar, sheet or plate.
Why Crestflo for A479-conforming instrumentation
- The pedigree's right there on paper. Components get machined from A479-conforming bar and shipped with an EN 10204 3.1 MTC (3.2 on request), plus a heat number on every part, which is exactly the traceability a pressure-vessel or PED audit expects.
- The A479 grades actually cover the range. 304, 304L, 316, 316L, 904L, Duplex 2205, Super Duplex 2507, and more, all supplied as finished instrumentation forms.
- A drop-in replacement, and a proven one. Fittings are tested for interchange per ASTM F1387; valves and manifolds are qualified to ASME B16.34 / API. A spec'd line gets replaced without any redesign.
- Lead time that actually moves projects along. Standard items sit in ready stock, specials get made to order, and delivery runs 6–8 weeks against the 20-plus weeks that's typical among the majors.
- Honest origin. Indian origin; US / European melt available on request, with full material traceability.
- Small MOQ and private label, both imperial and metric, customizable to requirement.
- Certified quality system: ISO 9001 / 14001 / 45001 & PED certified.
Crestflo is the instrumentation arm of a Government-of-India-recognized export house with four decades behind it and a long delivery record across the Middle East. Manufacturing runs deep in its history, but the brand itself is focused squarely on serving US customers. We Engineer Confidence.
Request an ASTM A479 quote
Send your requirement to Crestflo, grade/UNS, product form, size and quantity, plus any code (SA-479) or NACE overlay, and the Engineering Team will confirm the conforming grade, condition and documentation for your part.
RFQ, tell us what you need:
- Name
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- Requirement description (product, grade, size, quantity, service conditions)
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US contact: sales@crestflousa.com · +1 346 594 9005 · Houston, TX.
Frequently asked questions
What is ASTM A479?
ASTM A479 / A479M sets the ASTM International specification for stainless steel bars, hot- or cold-finished, in rounds, squares and hexagons, along with shapes like angles, tees and channels, meant for boilers and other pressure vessels. It lays out which grades are acceptable, the chemical and mechanical requirements, how heat treatment and testing are handled, and how the material gets marked. ASME has adopted it into its own code as SA-479.
What is the difference between ASTM A479 and ASTM A276?
Both cover stainless bar and shapes, but A479 is the pressure-vessel-qualified spec (ASME picked it up as SA-479), while A276 covers stainless bar and shapes more broadly. The grades and testing overlap quite a bit. Still, when the job is code-controlled boiler or pressure-vessel work, A479 / SA-479 is what gets called out.
What is ASTM A479 Grade 304 material?
A479 Grade/Type 304 (UNS S30400) is the standard austenitic 18Cr-8Ni stainless bar grade under A479. It's used where general corrosion resistance is what matters. 304L (S30403), by contrast, is the low-carbon variant meant for welded service. See the 304 / 304L material page.
What is the latest edition of ASTM A479?
ASTM revises A479 from time to time, so don't assume the copy you have is current. Check the ASTM catalog for the latest published edition, and cite whichever revision your project specification calls for, since edition references aren't the same across contracts.
What material is equivalent to ASTM A479?
There's no single equivalent, since A479 is a product-form spec rather than a material grade itself. Equivalence works two ways here. On the grade side, the same UNS chemistry (Type 316 equals UNS S31600, for instance) turns up in A276 bar stock and A182 F316 forgings alike. On the code side, it's ASME SA-479. So match by UNS number, then confirm the product form matches too.
Is ASME SA-479 the same as ASTM A479?
SA-479 is the ASME Boiler & Pressure Vessel Code's adopted version of ASTM A479. The two are technically equivalent, though which one you cite depends on the code of construction governing the job.
Which grades does ASTM A479 cover?
Austenitic grades (304/304L, 316/316L, 321, 347, 309, 310, XM-19), duplex austenitic-ferritic grades (2205 / S31803 / S32205, 2507 / S32750, S32760), super-austenitic 904L, and ferritic/martensitic grades such as 410 and 430 round out the family. The full list is set by the current edition, so check the grade table above.
Does ASTM A479 apply to duplex stainless like 2205 and 2507?
Yes. A479 covers austenitic-ferritic (duplex) grades such as UNS S31803/S32205 (2205) and S32750 (2507). Check the Duplex 2205 and Super Duplex 2507 material pages for more.
Does Crestflo supply parts made from A479-conforming bar?
Crestflo machines instrumentation valve bodies, fitting bodies, manifold bodies and bar-stock thermowells from A479-conforming stainless and duplex bar. Every part ships with an EN 10204 3.1 MTC (3.2 on request) and heat-number traceability. What Crestflo sells is finished instrumentation components, not raw bar or mill product.
Can I get an MTC and NACE compliance for A479 material?
Crestflo supplies EN 10204 3.1 / 3.2 material test certificates and PMI. For sour service, it also provides grades meeting NACE MR0175 / ISO 15156 requirements, with the qualified condition documented.
Where can I download the ASTM A479 PDF?
ASTM International owns the copyright on the full standard and sells it through its official webstore. This page just summarizes A479's scope, grades and requirements. It doesn't reproduce or distribute the document itself.
Explore related standards, materials & products
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Materials: 316 / 316L · 304 / 304L · 904L · Duplex 2205 · Super Duplex 2507 · 254 SMO · AL-6XN · Alloy 20
Products: Instrumentation valves · Tube fittings · Thermowells · 3-valve manifold
Guides: 304 vs 316 · 2205 vs 2507 · material selection by service