SAKYSTEEL supplies 316L BA stainless steel tubing for clean gas and liquid distribution systems that specify a bright-annealed surface. Bright annealing limits oxidation during heat treatment and preserves a bright surface. For clean-service applications, the tubing is selected together with the required internal surface condition, cleaning, end protection and packaging. BA is a practical choice where the project accepts this finish and does not require electropolishing.
Material: 316L / UNS S31603
Surface process: Bright annealed (BA); internal roughness specified separately
Common sizes: 1/4–1 in. OD in the combinations below; metric examples also listed
Construction: Seamless or welded, identified in the purchase specification
Clean-service requirements: Cleaning, drying, end caps, packaging and inspection scope defined for the application
Common OD and wall combinations are shown below. Select the tube size to match the connection dimensions, flow requirements and system design. Nominal metric equivalents are rounded.
| Tube OD (in.) | Tube OD (mm) | Wall (in.) | Wall (mm) |
|---|---|---|---|
| 1/4 | 6.35 | 0.035 | 0.89 |
| 3/8 | 9.53 | 0.035 | 0.89 |
| 1/2 | 12.70 | 0.049 | 1.24 |
| 3/4 | 19.05 | 0.065 | 1.65 |
| 1 | 25.40 | 0.065 | 1.65 |
Metric size examples: 6 × 1.0, 8 × 1.0, 10 × 1.0 and 12 × 1.0 mm (OD × wall). A 6 m length or your required cut length can be quoted. Inch and metric sizes are separate ordering choices; rounded conversions are for reference. These examples do not indicate current stock or a pressure rating.
| Item | Selection and ordering basis |
|---|---|
| Material and tube specification | 316L / UNS S31603. Identify ASTM A269 or the applicable project tubing specification, construction and edition. |
| Small-diameter specification | ASTM A632 may be considered only for sizes within its scope: OD from 0.050 in. to under 1/2 in., and wall from 0.005 in. to under 0.065 in. It does not cover every size in the table above. |
| Internal surface | BA surface condition plus any required maximum internal Ra, measurement method and inspection coverage. BA itself does not define a single Ra value. |
| Joining and connections | For orbital welding, identify end squareness, burr control and the dimensions required by the welding procedure. For tube fittings, check their tubing and surface requirements. |
| High-purity material criteria | Where SEMI F20 is specified, the required material criteria and supporting documentation must be confirmed for the order. |
| Clean delivery | Identify the required cleaning, drying, protection and packing conditions separately from the BA finish. |
BA identifies a heat-treatment and surface condition. An ordinary industrial tube may also be bright annealed, so a BA appearance alone does not establish high-purity suitability. The distinction lies in the complete purchase specification and verified delivery condition.
BA and EP tubing can both have explicit internal Ra requirements. Choose EP when electropolishing is required by the project, or when the proposed BA product cannot meet the specified surface acceptance criteria. Do not select EP solely because the inquiry includes an Ra value.
No. BA refers to bright annealing. Mechanical polishing uses abrasive processing, while electropolishing removes material electrochemically. A shiny outside surface does not identify the internal treatment or cleanliness.
BA does not define one universal roughness value. State the maximum internal Ra, units and inspection requirement. Acceptance should be based on the offered specification and agreed verification, rather than the BA designation alone.
Only if it satisfies the complete project specification. Review the material, internal surface, contamination controls, cleaning, drying, packaging and records. Bright annealing does not replace these checks.
Choose BA when the project permits a bright-annealed surface and the proposed tubing meets the required surface and cleanliness criteria. Choose EP when the specified process or surface acceptance requires it. Both choices still need appropriate material and clean delivery controls.
Confirm the tube construction, dimensions, end squareness, burr condition and cleanliness against the welding procedure. End preparation and protection should be specified with the order; the BA label alone does not mean weld-ready ends.
There is no single pressure rating for all BA tubing. The rating depends on material, OD, wall, tolerances, temperature, construction and the design basis; connections can also limit the system rating. Provide the design conditions for size and specification review.
Agree the required material and dimensional records, surface inspection and any roughness verification before ordering. Specify cleaning and drying acceptance where the service requires it. End caps and suitable bagging protect the tube after cleaning, but the packaging description alone is not a cleanliness certificate. Keep protective closures in place until the installation procedure requires removal.
Send the OD × wall, length, quantity, seamless or welded construction and service medium. Include the tubing standard, required internal Ra, connection or welding details, cleaning and packaging requirements, and inspection documents.