ASTM A276 vs A479 Stainless Steel Bars and Shapes

Overview

ASTM A276/A276M covers stainless steel bars and selected shapes for general corrosion-resistant and high-temperature uses, while ASTM A479/A479M covers stainless bars and shapes for boiler and other pressure-vessel construction. A shared alloy grade does not make the two specifications automatically interchangeable.

Designation and acceptance

A276/A276M-25 and A479/A479M-25 overlap in product forms such as rounds, squares, hexagons and selected hot-rolled or extruded shapes, but their intended construction context differs. A479 is explicitly tied to boilers and pressure vessels. Both interact with A484/A484M general requirements, and neither replaces the applicable equipment code, bar dimensions, heat-treatment condition or inspection obligations.

Members and selection

Designation	Selection context
A276 general bars	Use for hot- or cold-finished stainless bar in general applications when the product and project requirements permit A276.
A276 shapes	Angles, tees and channels require confirmation that the requested form, size and finish fall within the document and market route.
A479 pressure-service bars	Use where boiler or pressure-vessel construction invokes A479 and the construction code accepts the selected grade and condition.
A484 general requirements	Apply the referenced bar, billet, shape and forging general requirements, dimensional tolerances and order-precedence rules.

Comparison framework

Criterion	Decision context
Intended service	A276 is a general stainless bar and shape specification; A479 is directed to boiler and pressure-vessel construction.
Code relationship	A479 material conformity supports pressure construction but does not by itself approve a finished pressure component or design.
Delivery condition	Annealed, hardened and tempered, strain-hardened or other conditions must be selected from the applicable specification and grade.
Dual certification	A supplier may claim both only when the product independently satisfies both invoked specifications and the certificate demonstrates that basis.

Performance

Bar properties vary by alloy family, diameter or section, finishing route and heat-treatment condition.
Machinability and surface integrity depend on grade, inclusion control, cold work and finish rather than the ASTM number alone.
Pressure and elevated-temperature suitability requires construction-code, design stress and service review beyond room-temperature acceptance tests.

Orderable product scope

Round, square and hexagonal bars require size, length, straightness, finish and machining allowance.
Angles, tees and channels require section dimensions, tolerances, straightness and hot-rolled or extruded route clarification.
Pressure-component stock requires A479 when invoked, plus code-approved grade, heat treatment, test evidence and traceability.

Processing

Confirm hot-finished, cold-finished, peeled, turned, ground or polished condition before machining allowances are set.
Maintain the ordered heat-treatment condition through any subsequent thermal processing and document requalification when it changes.
For pressure construction, connect material heat numbers to component traceability and the fabricator's approved quality system.

Applications

A276 bars for shafts, fasteners, machined components, supports and general corrosion-resistant fabrications.
A276 shapes for frames and supports where section availability and tolerance match the design.
A479 bars and shapes for boiler or pressure-vessel components when required by the governing construction documents.

Selection

Begin with the equipment or project document: choose A479 when pressure construction requires it, not merely because the alloy is stainless.
Verify the exact form, grade, condition, size range and property requirements in the selected product specification.
Require written technical comparison and code approval before substituting A276 for A479 or accepting an unstated dual certification.

Procurement

State ASTM A276/A276M-25 or ASTM A479/A479M-25; do not write A276/A479 as an undefined combined standard.
State grade/UNS, bar or shape form, hot- or cold-finished route, condition, dimensions, length and quantity.
Define surface, straightness, dimensional tolerances, mechanical tests, corrosion tests where invoked and any supplementary requirements.
For A479 orders, state construction code, inspection authority, certificate, traceability, marking and pressure-service additions.

Request a sourcing review

Sources and review

ASTM A276/A276M-25 - Stainless Steel Bars and Shapes

ASTM International · 2025, active

ASTM A479/A479M-25 - Stainless Steel Bars and Shapes for Boilers and Pressure Vessels