Bright Annealed Cold Drawn Stainless Steel Tubing Seamless Tube for Automotive Applications
Bright Annealed Stainless Steel Tubing (Cold-Drawn Seamless) for Automobiles
Material Overview
Bright Annealed (BA) stainless steel tubing is a cold-drawn seamless tube that is solution annealed in a controlled, oxygen-free (reducing or inert) atmosphere to preserve a clean, bright metallic surface on both the OD and ID, while restoring ductility after cold working.
For automotive systems, BA seamless tubing is typically selected when you need:
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High corrosion resistance and long service life
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Excellent bending/flaring performance for assembly
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Clean internal surface for fluids and gases
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Premium appearance for exposed routing and trim
Specifications
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Manufacturing: Seamless tube → cold drawn to size → bright annealed (BA)
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Typical supply form: Straight lengths or coils (depending on OD/wall), ends deburred and capped
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Dimension range (customizable): OD / ID / wall thickness to drawing; common automotive sizes include small OD thin-wall tubing for hard lines and sensor routing
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Surface condition: Bright annealed OD/ID; optional polishing, passivation, or special roughness targets upon request
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Inspection & testing: Chemistry/traceability by heat & lot; hydrostatic test or nondestructive electric test available per ASTM A269 unless otherwise specified
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Documentation: Mill Test Certificate (MTC) with full traceability; optional PMI and third-party inspection
Key Features
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High surface quality: BA processing minimizes oxidation/discoloration, helping maintain a clean, reflective surface.
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Excellent formability: Solution annealed condition supports tight-radius bending, beading, and flaring for automotive connections.
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Corrosion resistance: Austenitic stainless grades (304/316L/321/347) provide strong resistance in many automotive fluids and environments.
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Leak-risk reduction: Consistent dimensional control plus NDT/hydrostatic test options support reliable sealing in hard-line assemblies.
Our Advantages
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“Will the tube stay bright and clean inside/outside after annealing?”
We use BA practice intended to limit oxidation by processing in controlled, oxygen-free atmospheres; this helps preserve metallic luster and can reduce the need for aggressive post-cleaning steps. -
“How do you reduce cracking risk during bending/flaring and improve assembly yield?”
Tubes are supplied in the heat-treated condition required for austenitic stainless tubing (solution heat treated). This restores ductility after cold drawing, improving flaring/bending performance for automotive routing and end-forming. -
“How do you verify pressure integrity and compliance for OEM purchasing?”
If ASTM A269 is specified, each tube can be qualified by hydrostatic test or nondestructive electric test (per the standard, manufacturer option unless the PO specifies otherwise). This supports consistent QA for brake/fuel/transmission and similar hard-line applications.
Chemical Composition
| Grade (ASTM) | UNS | C (max) | Mn (max) | P (max) | S (max) | Si (max) | Cr | Ni | Mo | Stabilizing element |
|---|---|---|---|---|---|---|---|---|---|---|
| TP304 | S30400 | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 18.0–20.0 | 8.0–11.0 | — | — |
| TP304L | S30403 | 0.035 | 2.00 | 0.045 | 0.030 | 1.00 | 18.0–20.0 | 8.0–12.0 | — | — |
| TP316L | S31603 | 0.035 | 2.00 | 0.045 | 0.030 | 1.00 | 16.0–18.0 | 10.0–15.0 | 2.00–3.00 | — |
| TP321 | S32100 | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 17.0–19.0 | 9.0–12.0 | — | Ti: ≥ 5×(C+N), ≤ 0.70 |
| TP347 | S34700 | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 17.0–19.0 | 9.0–12.0 | — | Nb(Cb): ≥ 10×C, ≤ 1.10 |
Mechanical Properties
| Grade (ASTM) | Tensile Strength (min) | Yield Strength (min) | Elongation (min) | Hardness (max) |
|---|---|---|---|---|
| TP304 | 515 MPa (75 ksi) | 205 MPa (30 ksi) | 35% | 192 HBW / 200 HV / 90 HRB |
| TP304L | 485 MPa (70 ksi) | 170 MPa (25 ksi) | 35% | 192 HBW / 200 HV / 90 HRB |
| TP316L | 485 MPa (70 ksi) | 170 MPa (25 ksi) | 35% | 192 HBW / 200 HV / 90 HRB |
| TP321 | 515 MPa (75 ksi) | 205 MPa (30 ksi) | 35% | 192 HBW / 200 HV / 90 HRB |
| TP347 | 515 MPa (75 ksi) | 205 MPa (30 ksi) | 35% | 192 HBW / 200 HV / 90 HRB |
Execution Standards
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ASTM: ASTM A269/A269M; ASTM A213/A213M
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EN: EN 10216-5
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GOST: GOST 9941
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JIS: JIS G3459
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GB: GB/T 13296
Application Fields
Main field: Automotive fluid transfer, sensing, and thermal systems.
Where it is used (examples):
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Brake / fuel / transmission / oil cooler hard lines: Stainless hard lines are commonly offered for these systems, and ASTM A269 is frequently referenced for stainless tubing in such line products.
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Corrosion-resistant routing in harsh environments: Underbody routing where road salts and moisture accelerate corrosion
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Sensor and instrumentation lines: Where internal cleanliness and stable ID are critical
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High-temperature sections (grade-dependent): Near exhaust/EGR/turbo areas where stabilized grades (321/347) can be beneficial
Q: Are you trading company or manufacturer ?
A: manufacturer,also can do trading.
Q: How long is your delivery time?
A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,
it is according to quantity.
Q: Do you provide samples? is it free or extra ?
A: Yes, we could offer the sample for free charge but need pay the cost of freight.
Q: What is your terms of payment ?
A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.
If you have another question, pls feel free to contact with me.
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