ASTM Standards for 1.4306 Stainless Steel
ASTM Standards for 1.4306 Stainless Steel: 304L Plate, Pipe, and Bar Specifications Explained
1.4306 stainless steel, often identified as AISI 304L, is a low-carbon austenitic stainless steel widely used in industries requiring excellent corrosion resistance and weldability. In the U.S., this material is covered under several ASTM standards, each specifying the product form, mechanical properties, and testing requirements.
This article provides an in-depth overview of the ASTM standards for 1.4306 stainless steel, including detailed comparisons such as ASTM A312 vs A269 tubing, and ASTM A276 bar vs A240 sheet specifications-helping engineers, buyers, and fabricators make informed material choices.
ASTM Standards for 1.4306 / AISI 304L Stainless Steel
Here is a breakdown of the most commonly used ASTM standards relevant to 1.4306 / 304L stainless steel:
| ASTM Standard | Product Form | Main Features |
|---|---|---|
| ASTM A240 | Plate, Sheet, and Strip | Used in pressure vessels and structural applications |
| ASTM A312 | Seamless and Welded Pipes | For corrosive and high-temperature piping |
| ASTM A269 | Tubing for General Service | Lower pressure, often used in fluid systems |
| ASTM A270 | Sanitary Tubing | High cleanliness required in food and pharmaceutical |
| ASTM A276 | Hot/Cold Finished Bars and Shapes | Suitable for machining, structural use |
| ASTM A666 | Sheet and Plate Mechanical Properties | Defines temper and forming capability |
304L ASTM A240 Sheet Specification (1.4306)
ASTM A240 covers 304L (1.4306) stainless steel in sheet, plate, and strip form. Key specification highlights:
Thickness Range: Typically from 0.3 mm to 50 mm
Finish Options: 2B, BA, No.4, No.8 (mirror)
Mechanical Properties (Annealed Condition):
Yield Strength (min): 170 MPa
Tensile Strength (min): 485 MPa
Elongation: ≥ 40%
Corrosion Resistance: Excellent in mildly corrosive environments
Applications: Pressure vessels, tanks, kitchen equipment, architectural panels
ASTM A312 vs A269 Tubing: What's the Difference?
Both ASTM A312 and ASTM A269 cover 304L / 1.4306 stainless steel tubing, but they serve different purposes:
| Aspect | ASTM A312 | ASTM A269 |
|---|---|---|
| Application | High-pressure piping systems | Low-pressure/general service |
| Wall Thickness | Heavier wall (Schedule 10 to XXS) | Lighter wall thicknesses |
| Surface Finish | Pickled or bright-annealed | Usually polished or annealed |
| Testing Requirements | Hydrostatic or NDT (e.g., X-ray) | Less stringent, no X-ray needed |
| Use Case Examples | Chemical processing, power plants | Heat exchangers, fluid transfer |
Summary: Use A312 for critical pressure and temperature conditions, and A269 for standard fluid systems.
ASTM A276 304L Stainless Steel Bar Specification
ASTM A276 specifies hot-finished or cold-finished bars and shapes of stainless steel, including 1.4306 / AISI 304L:
Common Forms: Round bar, square bar, flat bar, hexagon bar
Surface Finish: Peeled, polished, ground, or turned
Applications: Shafts, fasteners, supports, and machined parts
Hardness: Typically below 95 HRB (annealed condition)
Formability & Weldability: Excellent, thanks to low carbon content
Low Carbon Stainless Steel ASTM Specification
1.4306 is classified as a low-carbon version of 304 stainless steel. Compared to standard 304, its maximum carbon content is just 0.030%, reducing the risk of intergranular corrosion after welding.
| Grade | Carbon Max (%) | Typical Use |
|---|---|---|
| 304 | 0.08 | General structural and utility use |
| 304L / 1.4306 | 0.030 | Welded structures, tanks, piping |
Low-carbon stainless steels like 1.4306 are essential in pressure vessels, chemical tanks, and welded pipe systems where corrosion resistance at weld seams is critical.
AISI 304L vs 1.4306 Equivalent Comparison
Though often used interchangeably, AISI 304L and EN 1.4306 have subtle differences:
| Property | AISI 304L | EN 1.4306 |
|---|---|---|
| Standard System | ASTM / SAE (USA) | EN 10088-2 (Europe) |
| Nickel Content | 8.0–12.0% | 10.0–13.0% (higher for corrosion resistance) |
| Carbon Content | ≤ 0.030% | ≤ 0.030% |
| Use Case Focus | General industry | Pharmaceuticals, ultra-clean applications |
Conclusion: 1.4306 is essentially a higher-purity version of 304L, with elevated nickel for better corrosion performance, especially in hygienic or high-spec environments.
