What ASTM A276 Covers
ASTM A276 is the general-purpose standard for stainless steel long products supplied as bar and simple shapes. It applies to wrought material in the hot-worked, cold-worked, annealed, or heat-treated condition and sets the chemical composition limits, mechanical property minimums, and permitted dimensional tolerances that a mill must meet before a heat can be certified to the specification.
The scope includes the familiar bar sections buyers order every day:
- Round bar (the most common form)
- Square and flat bar
- Hexagon bar
- Angles, tees, and other hot-rolled shapes
Because A276 spans austenitic, ferritic, martensitic, and duplex families, a single purchase order can call out the grade and the mechanical condition without switching specifications. For bar destined specifically for boiler and pressure-vessel internals, the closely related ASTM A479 stainless steel bar standard applies the same chemistry but adds the construction-code mechanical and testing requirements.
A276 and the Round-Bar Product Range
Every A276 grade we carry is held ex-stock as finished stainless steel round bar, part of our wider round-bar program. Material is cut and dispatched immediately, and every order ships with an EN 10204 3.1 (or 3.2 on request) mill test certificate.
Grades Supplied to ASTM A276
The austenitic grades dominate corrosion-resistant bar work. The table below lists the grades we stock to A276 with their UNS numbers and the attribute that drives grade selection.
| Grade | UNS | Family | Selection driver |
|---|---|---|---|
| 304 | S30400 | Austenitic | General corrosion resistance, workhorse grade |
| 304L | S30403 | Austenitic | Low carbon (C ≤ 0.03%) for welded parts |
| 316 | S31600 | Austenitic | 2–3% Mo for chloride pitting resistance |
| 316L | S31603 | Austenitic | Low carbon plus molybdenum for welded chloride duty |
| 321 | S32100 | Austenitic | Titanium-stabilized against sensitization |
| 347 | S34700 | Austenitic | Niobium-stabilized for elevated temperature |
| 310 | S31000 | Austenitic | High-temperature oxidation resistance |
| 904L | N08904 | Super-austenitic | ~4.5% Mo, copper-bearing, sulfuric-acid service |
Chemistry That Drives Bar Selection
A276 fixes the composition window for each grade. The elements below are the ones that decide which bar you specify:
| Grade | Carbon | Chromium | Nickel | Molybdenum | PREN (approx.) |
|---|---|---|---|---|---|
| 304 / 304L | 304L ≤ 0.03% | 18–20% | 8–10.5% | – | ~18 |
| 316 / 316L | 316L ≤ 0.03% | 16–18% | 10–14% | 2–3% | ~24 |
| 904L | ≤ 0.02% | 19–23% | ~25% | ~4.5% | ~34 |
The molybdenum content is what separates 316 from 304 on pitting resistance, and the copper-bearing, high-molybdenum chemistry of 904L super-austenitic stainless is what lets it resist sulfuric acid where 316 cannot. For the full method behind these numbers, see the PREN and pitting resistance guide.
Mechanical Conditions Under A276
A276 lists mechanical property minimums for each grade in the condition supplied. Austenitic bar is normally furnished solution-annealed, which gives the best corrosion resistance and ductility; cold-finished bar carries higher strength and tighter tolerances for machining. Typical annealed austenitic minimums are a tensile strength around 515 MPa (75 ksi), yield (0.2% offset) around 205 MPa (30 ksi), and elongation near 40%, with hardness capped by grade.
When bar will be welded and then held in the 425–815 °C range, specify an L grade to avoid sensitization and the intergranular attack that follows. The guide to preventing sensitization and the intergranular corrosion explainer cover why the low-carbon grades matter for machined and welded assemblies.
How to Choose the Right A276 Grade
Grade selection for bar follows the same logic as for plate and sheet: match the alloy to the real service environment, not to habit.
- General and indoor duty: 304 or 304L bar handles most non-chloride fabrication. See general fabrication applications.
- Chloride, marine, and coastal exposure: step up to 316 or 316L for the molybdenum. Compare the two families in 304 vs 316 and 304L vs 316L.
- Hot concentrated chlorides or sulfuric acid: move to 904L before reaching for more expensive alloys.
- Elevated temperature: 321, 347, or 310 hold up where plain 304 would scale or sensitize.
A common and costly error is defaulting to 304 for chloride-adjacent or coastal duty, where it pits. Confirm the actual service chlorides before choosing 304 over 316, since stepping up is far cheaper than a failed component. Our stainless grade selection guide and grade selector tool walk through the decision.
Related Standards and Forms
A276 governs bar and shapes; neighboring specifications cover the same alloys in other product forms and services.
| Standard | Scope |
|---|---|
| ASTM A479 | Stainless bar for boilers and pressure vessels |
| ASTM A240 | Stainless plate, sheet, and strip |
| ASTM A182 | Forged stainless flanges, fittings, and valve parts |
| ASTM B446 | Inconel 625 nickel-alloy bar and rod |
For nickel-alloy long products outside the stainless range, bar is supplied to the relevant ASTM B-series specification rather than A276.
Quality, Testing, and Traceability
Every bar order is backed by an EN 10204 3.1 or 3.2 mill test certificate, confirming chemistry and mechanical properties against the A276 limits for the supplied heat. Material comes from genuine mill sources, and third-party inspection by TÜV SÜD, Bureau Veritas, DNV, SGS, or ABS can be arranged. Nandini Steel has been an ISO 9001:2015-certified stockist and supplier since 2003, with full material traceability from heat to dispatch.
Frequently Asked Questions
What is ASTM A276?
What is the difference between ASTM A276 and ASTM A479?
Which stainless grades are available as A276 bar?
Does A276 bar come with a mill test certificate?
What forms and sizes does A276 cover?
Request a Quote
Need A276 stainless bar cut to size? Contact Nandini Steel for live pricing and ex-stock availability. Call +91 22 43404600, WhatsApp +91 99202 09184, email reachus@nandinisteel.com, or send an RFQ through our contact page.