Fabrication
What is a BA finish tube and when is it required?
BA means bright annealed: the tube is annealed in a controlled reducing atmosphere so it leaves the furnace with a clean, bright, scale-free surface needing no pickling. It is specified where surface cleanliness and low roughness matter — pharmaceutical, food, semiconductor and high purity gas and instrument lines.
Bright annealing is a heat treatment carried out in hydrogen or a hydrogen-nitrogen atmosphere. Because no oxygen reaches the steel, no oxide scale forms, so the tube does not need pickling and the surface retains a smooth, reflective finish with a typical internal roughness of 0.4 to 0.8 micrometre Ra.
That matters where the surface itself is a functional requirement:
- Pharmaceutical and biotech — clean-in-place systems and WFI loops, where roughness drives cleanability and biofilm risk. Electropolishing often follows.
- Food and dairy — hygienic process lines to 3-A or EHEDG practice.
- Semiconductor and high purity gas — particle shedding and outgassing must be minimal.
- Instrument and hydraulic tubing — a clean bore and tight tolerance give reliable compression fitting seals.
When enquiring, state the grade (316L is most common), OD and wall, the required internal Ra, whether electropolishing is needed, and the test and documentation package — typically EN 10204 3.1 with PMI, hydrostatic or eddy current test results and a surface roughness report.
Axicor supplies BA finish tubing in stainless and nickel alloy grades alongside heat exchanger, boiler and finned tube product lines.
Need this confirmed for your job?
Send the duty, the size and the certification you need. We answer with a grade, a stock position and a price — not a brochure.
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