ASTM A276 vs A479 vs ASME SA-479: Stainless Steel Bar Guide

Quick answer

ASTM A276 and ASTM A479 are not automatic substitutes. ASTM A276/A276M covers general stainless steel bars and shapes. ASTM A479/A479M covers stainless steel bars and shapes for boiler and pressure vessel construction. ASME SA-479 is the corresponding material-specification wording used in the ASME code system.

The product forms overlap: round, square and hex bar appear in both specifications, along with certain hot-rolled or extruded shapes. The application scope is what changes the purchasing decision. If a drawing, pressure-equipment specification or end user names A479 or SA-479, an A276 certificate should not be accepted merely because the grade and chemistry look similar.

Before ordering, confirm the exact standard, edition, grade or UNS number, bar form, dimensions, delivery condition, required tests and MTC wording.

ASTM A276 vs A479 vs ASME SA-479

The comparison below is a purchasing summary, not a replacement for the official standards.

Both ASTM specifications cover more than chemistry. ASTM's public summaries describe mechanical-property testing for A276 and A479. A479 also contains heat-treatment and corrosion-test requirements for applicable grades and conditions. The exact requirement depends on the grade, product condition, ordered edition and purchase document.

As of 16 August 2026, ASTM lists A276/A276M-24a and A479/A479M-24 as active editions. A buyer should still use the edition named by the drawing, contract or governing code rather than silently replacing it with a newer edition.

Can ASTM A276 replace ASTM A479?

No, not by default.

A 316L heat may fall within the same UNS chemistry range whether the inquiry begins with A276 or A479. That does not prove that the bar was produced, heat treated, tested and certified to both specifications. Standard compliance is supported by the applicable manufacturing and test records, not by adding another designation to an existing MTC.

Hold the substitution when any of these conditions apply:

• the drawing or PO explicitly states ASTM A479 or ASME SA-479;
• the component enters a boiler, pressure vessel or code-controlled supply chain;
• the project requires a named heat-treatment condition or corrosion test;
• the end user must approve material substitutions;
• the available MTC does not show the ordered specification and required test results.

If the project accepts either specification, write that acceptance into the PO before production. Do not resolve the question after the bars have been cut or shipped.

What ASTM A276 covers

ASTM A276/A276M covers hot-finished or cold-finished stainless steel bars, except bars intended for reforging. Its public scope includes rounds, squares and hexagons, plus hot-rolled or extruded shapes such as angles, tees and channels.

This is common starting language for stainless steel round bar, hex bar and square bar used in machining, fabrication and general industrial parts. A typical 304 order might state:

ASTM A276/A276M 304 stainless steel round bar, 25 mm diameter, cold-finished condition, diameter tolerance per drawing, 3 m length, MTC and heat-number tags required.

A276 is not shorthand for every stainless bar route. ASTM points free-machining stainless bars toward ASTM A582/A582M, and bars for reforging toward ASTM A314. The correct standard should follow the material route and final application.

What ASTM A479 adds for pressure-related purchasing

ASTM A479/A479M is written for stainless steel bars and shapes used in boiler and pressure vessel construction. The covered forms can look similar to A276 stock, but the project context changes what must be confirmed.

For a 316L bar entering a pressure-related order, buyers commonly need to settle:

• the exact ASTM A479/A479M edition;
• grade and UNS wording, such as 316L / UNS S31603;
• bar form, size and hot- or cold-finished condition;
• specified heat treatment or delivery condition;
• tensile, yield, elongation and hardness results where applicable;
• corrosion testing where the ordered grade and specification require it;
• heat-number traceability from MTC to each bundle;
• any supplementary project, third-party or end-user requirement.

A479 does not turn a vague request for "316L pressure bar" into a complete specification. The drawing and PO still control dimensions, tolerances, condition, test scope and acceptance.

For the product route, see 316/316L stainless steel bar and 316L stainless steel round bar.

ASTM A479 and ASME SA-479 are related, but edition control matters

ASME SA-479 is the designation used when the A479 material specification is adopted within the ASME Boiler and Pressure Vessel Code material system. In purchasing emails, ASTM A479 and ASME SA-479 are often written together. That does not remove edition control.

The governing ASME Code edition or project specification may reference a particular SA-479 edition. A current ASTM edition should not be substituted automatically for the edition accepted by the code user, inspector or end customer.

A practical PO should avoid loose wording such as:

316L bar, A479 equivalent.

Use exact language instead:

316L / UNS S31603 stainless steel round bar, ASME SA-479, edition as required by the project specification, 40 mm diameter, condition and tests per PO, MTC with heat-number traceability required.

Also remember that SA-479 material alone does not certify the finished valve, vessel part or pressure component. Design, fabrication, welding, examination and project authorization sit outside the bar MTC.

A276/A276M and A479/A479M: do not mix unit systems

The slash-M designation is not decorative. A276/A276M and A479/A479M provide inch-pound and SI routes, and the order should state the designation that matches the drawing and dimensions.

For an order written in millimetres and megapascals, confirm whether the buyer requires the A276M or A479M designation. Do not combine an inch-pound tolerance table with SI dimensions and assume the result remains compliant.

This detail is especially useful for buyers in Vietnam, Thailand, Malaysia and Indonesia, where drawings are commonly metric while imported project documents may retain ASTM or ASME wording.

MTC checks before payment or shipment release

The MTC should prove the material supplied against the ordered requirement. For A276, A479 or SA-479 bar, check these fields before release:

Do not ask the supplier to add A479 or SA-479 wording after production unless the original manufacturing and test records support that certification. If the MTC and PO name different standards, hold release and resolve the mismatch in writing.

The MTC checklist before shipment covers the document, label and packing-list workflow in more detail.

Two RFQ examples

For ordinary machining stock:

ASTM A276/A276M 304 stainless steel round bar, 20 mm diameter, cold-finished, tolerance per drawing, 3 m length, 2 MT. MTC and heat-number bundle labels required. Please quote FOB China port and state the available standard edition.

For a pressure-related project:

316L / UNS S31603 stainless steel round bar, ASTM A479/A479M or ASME SA-479 as stated in the attached project specification, 35 mm diameter, required condition and tests per PO, 1.5 MT. Submit a sample MTC for document approval before production. Destination: Laem Chabang, Thailand.

The second inquiry should include the project specification rather than asking the supplier to decide which pressure-code wording applies.

Common ordering mistakes

• Treating matching 316L chemistry as proof that A276 and A479 are interchangeable.
• Writing "A479 equivalent" without naming the accepted standard and edition.
• Assuming every current ASTM edition is accepted by the governing ASME code.
• Omitting the delivery or heat-treatment condition.
• Requesting SA-479 only after the available stock MTC has been issued.
• Checking the certificate after the bars have already been shipped.
• Expecting material certification to also cover compliance for the finished pressure component.

Clear PO wording prevents most of these problems before production starts.

Official sources and limits

The official ASTM product pages used for this update are:

• ASTM A276/A276M-24a, Standard Specification for Stainless Steel Bars and Shapes
• ASTM A479/A479M-24, Standard Specification for Stainless Steel Bars and Shapes for Use in Boilers and Other Pressure Vessels

This article summarizes public scope and procurement implications. It does not reproduce the paid standard text or replace engineering, code-user or authorized-inspector approval. Confirm ASME SA-479 against the applicable ASME Code edition and project documents.

Frequently asked questions

Send the standard and project wording with your inquiry

Send the grade, UNS number, bar form, size, condition, standard, required edition, test scope, quantity and destination through the stainless steel bar quote page. We will check the available material and certificate route against the wording you provide before issuing the quotation.