If precision, purity, and a flawless surface finish are things that cannot be compromised, 304 Stainless Steel Bright Annealed Tubes are up to the task. Metinox Overseas is a reputed manufacturer, supplier and exporter of SS304 BA tubes from Mumbai, India who supply tubes to pharmaceutical, food processing, semiconductor, instrumentation, and chemical processing industries across India and 14 export markets like pharmaceuticals, food processing, biotechnology, instrumentation, chemical processing and energy etc. Bright annealed tubes are produced in an oxygen free furnace environment to help eliminate oxidation to achieve a smooth reflective, mirror-like surface on the inside and outside of the tubes without the need to pickling or passivate. Made to ASTM A269, A249, A270 and A213 standards, each tube is subjected to stringent quality control to ensure that outer diameter and wall thickness comply with ASTM A269 dimensional tolerances, with tighter in-house precision tolerances available on request for instrumentation applications. With detailed Mill Test Certificates, complete material traceability, and the support of third-party inspection services, Metinox Overseas provides you a trusted partner for the high-quality SS 304 bright annealed tubing, offered in seamless and welded types, and customizable to your project needs.
What are 304 Stainless Steel Bright Annealed Tubes?
The 304 Stainless Steel Bright Annealed Tubes are high-performance austenitic stainless steel tubes which have been treated with a special heat treatment procedure in a controlled oxygen-free atmosphere. Bright annealing is different from conventional annealing, which is performed in ambient air and leads to surface oxidation and scaling; In bright annealing, the oxide formation is completely avoided by performing the process in an inert gas atmosphere, usually a mixture of hydrogen and nitrogen gas.
The outcome is a tube with an exceptionally smooth surface finish with a mirror effect for both the inner bore and outer wall. For applications in which contamination needs to be removed, regulatory cleanliness standards apply, and the surface needs to be accurately controlled in order to provide precise fluid dynamics within the bore, this ultra-clean surface is essential.
The Grade 304 alloy (UNS S30400 / DIN 1.4301) is the most popular austenitic stainless steel grade for its superior corrosion resistance, ease of forming and wide-temperature-temperature range that makes it ideal for use in a wide variety of applications. These properties are also improved when the tubes are bright annealed, making SS 304 BA tubes the material of choice for pharmaceutical, biotechnology, food- grade and precision instrumentation applications worldwide.
Why Choose Metinox Overseas?
- Decades of experience in stainless steel tube manufacturing and export
- In-house bright annealing furnaces with precise atmosphere control
- 100% compliance with ASTM, DIN, JIS, EN, and AISI standards
- Tight OD/WT tolerances: ±0.05 mm for precision-critical applications
- Comprehensive documentation: MTCs (EN 10204 3.1/3.2), dimensional reports, hydrostatic test certificates
- Flexible supply: small batch to large project quantities
- Fast lead times with air and sea freight export capability from Mumbai
Table of Contents
- SS 304 Bright Annealed Tubes Specification
- SS 304 BA Pipes and Tubes Chemical Composition
- Mechanical Properties of SS 304 Bright Annealed Tubes
- Equivalent International Grades of SS 304 BA Tubes
- SS 304 Bright Annealed Tube Price
- SS 304 Bright Annealed Tube Sizes
- Bright Annealing Process & Manufacturing Quality
- Product Types & Variants
- Applications & Industries Served
- Standards, Certifications & Quality
- FAQs
SS 304 Bright Annealed Tubes Specification
| Parameter | Details |
|---|---|
| Standard | JIS, ASTM, GB, DIN, EN, AISI |
| Specifications | ASTM A312, A249, A269, A270, A213, A511 |
| Thickness Range | 0.25 mm - 2 mm |
| Outer Diameter (OD) | 3 mm - 50.8 mm |
| Material | 300 & 400 Series Stainless Steel |
| Type | Seamless, Welded (ERW) |
| Finish | Bright Annealed (BA) - Inside and Outside |
| OD Tolerance | +/- 0.05 mm |
| WT Tolerance | +/- 0.05 mm |
| End Condition | Plain End / Beveled End |
SS 304 BA Pipes and Tubes Chemical Composition (% by weight)
| Grade | C (max) | Ni | Si (max) | N (max) | S (max) | Mn (max) | P (max) | Cr | Mo |
|---|---|---|---|---|---|---|---|---|---|
| SS 304 | 0.08 | 8.0-10.5 | 0.75 | 0.10 | 0.030 | 2.0 | 0.045 | 18.0-20.0 | - |
Mechanical Properties of SS 304 Bright Annealed Tubes
| Grade | Tensile Strength (MPa) min | Elongation (% in 50mm) min | Yield Strength 0.2% Proof (MPa) min | Rockwell B (HRB) max | Brinell (HB) max |
|---|---|---|---|---|---|
| SS 304 | 515 | 40 | 205 | 92 | 201 |
Equivalent International Grades of SS 304 BA Tubes
| Standard | UNS | Werkstoff Nr. | AFNOR | EN | JIS | BS | GOST |
|---|---|---|---|---|---|---|---|
| SS 304 | S30400 | 1.4301 | Z7CN18-09 | X5CrNi18-10 | SUS 304 | 304S31 | 08X18H10 |
SS 304 Bright Annealed Tube Price (Indicative)
| OD (mm) | Thickness (mm) | Price Per Meter (INR) |
|---|---|---|
| 6.35 | 0.89 | Rs. 180 - Rs. 250 |
| 9.52 | 0.89 | Rs. 240 - Rs. 320 |
| 12.70 | 1.24 | Rs. 350 - Rs. 480 |
| 15.88 | 1.24 | Rs. 450 - Rs. 600 |
| 19.05 | 1.65 | Rs. 650 - Rs. 850 |
| 25.40 | 1.65 | Rs. 950 - Rs. 1,250 |
| 31.75 | 1.65 | Rs. 1,350 - Rs. 1,800 |
| 38.10 | 1.65 | Rs. 1,900 - Rs. 2,500 |
| 50.80 | 2.11 | Rs. 3,000 - Rs. 4,000 |
Note: Prices vary based on mill origin, quantity, wall thickness, surface finish, and current nickel prices.
SS 304 Bright Annealed Tube Sizes
| OD (Inch) | OD (mm) | Common Thickness (mm) |
|---|---|---|
| 1/8" | 3.18 | 0.50, 0.71 |
| 1/4" | 6.35 | 0.71, 0.89, 1.24 |
| 3/8" | 9.52 | 0.71, 0.89, 1.24 |
| 1/2" | 12.70 | 0.89, 1.24, 1.65 |
| 5/8" | 15.88 | 1.24, 1.65 |
| 3/4" | 19.05 | 1.24, 1.65, 2.11 |
| 1" | 25.40 | 1.24, 1.65, 2.11 |
| 1-1/4" | 31.75 | 1.65, 2.11 |
| 1-1/2" | 38.10 | 1.65, 2.11 |
| 2" | 50.80 | 2.11, 2.77 |
| 2-1/2" | 63.50 | 2.77, 3.05 |
| 3" | 76.20 | 2.77, 3.05 |
| 4" | 101.60 | 3.05, 3.40 |
Bright Annealing Process & Manufacturing Quality
How the Bright Annealing Process Works
The bright annealing process is a precision heat treatment method that transforms standard stainless steel tube into a high-value, ultra-clean product. Here is the step-by-step process used at Metinox Overseas:
- Raw Material Inspection: Incoming stainless steel coils or tube blanks are inspected for chemical composition using PMI (Positive Material Identification) and dimensional verification.
- Tube Forming: Material is formed into seamless or welded tube profiles using cold drawing or ERW (Electric Resistance Welding) processes.
- Degreasing & Cleaning: Tubes are thoroughly cleaned to remove surface oils, debris, and contaminants before entering the furnace.
- Furnace Bright Annealing: Tubes are passed through a continuous belt furnace at 1,000°C-1,200°C in a hydrogen/nitrogen (H2/N2) inert atmosphere. The oxygen-free environment prevents any surface oxidation or scaling.
- Controlled Cooling: Tubes are rapidly cooled within the protective atmosphere to lock in the refined microstructure and preserve the bright surface.
- Final Inspection & Testing: Each batch undergoes dimensional inspection (OD, WT, length), surface finish assessment, hydrostatic testing, eddy current testing (for seamless grades), and visual inspection.
- Documentation & Dispatch: Mill Test Certificates, packing lists, and inspection reports are prepared before shipment.
Standard Annealing vs. Bright Annealing - Key Differences
| Feature | Standard Annealing | Bright Annealing (BA) |
|---|---|---|
| Atmosphere | Normal air / oxidizing | Oxygen-free (H2 / N2 gas) |
| Surface Finish | Dull grey with oxide scale | Shiny, mirror-like, reflective |
| Post-treatment | Pickling/passivation needed | None required |
| Corrosion Resistance | Standard | Superior (no scale layer) |
| Cleanliness | Surface contamination risk | Ultra-clean, hygienic |
| Dimensional Accuracy | Standard tolerance | +/- 0.05mm (tight tolerance) |
| Applications | General structural use | Pharma, food, instrumentation |
Product Types & Variants
Stainless Steel 304 Bright Annealed Tubes - Available Types
Metinox Overseas supplies SS 304 bright annealed tubes in a comprehensive range of types to suit every industrial requirement:
- SS 304 BA Seamless Round Tubes - Cold drawn, no weld seam, superior pressure rating
- SS 304 BA Welded (ERW) Round Tubes - Cost-effective option for fluid service and general-purpose applications
- SS 304 BA Square Tubes - Structural and decorative applications requiring bright finish
- SS 304 BA Rectangular Tubes - Instrumentation frames, architectural features
- SS 304 BA Capillary Tubes - Ultra-small OD for analytical instruments, medical devices
- SS 304 BA Heat Exchanger Tubes - Thin-walled, precision tubes for thermal applications
- SS 304 BA Instrumentation Tubes - Tight OD tolerances for hydraulic and pneumatic control lines
- SS 304 BA U-Bend Tubes - Pre-formed for heat exchanger bundle assemblies
- SS 304 BA Sanitary/Hygienic Tubes - ASTM A270 compliant for food, beverage, and pharma
- ASME SA213 / ASME SA249 BA Tubes - Pressure vessel and boiler-grade applications
Applications & Industries Served
Where SS 304 Bright Annealed Tubes Are Used
| Industry | Application | Key Advantage |
|---|---|---|
| Pharmaceuticals | High-purity fluid transfer lines | Contamination-free, mirror finish |
| Food & Beverage | Hygienic processing pipelines | FDA-compliant smooth surface |
| Chemical Processing | Corrosive media transport | Superior corrosion resistance |
| Biotechnology | Sterile process tubing | Ultra-clean bright annealed bore |
| Instrumentation | Precision sensor & control lines | Tight OD/WT tolerances |
| Refrigeration & HVAC | Refrigerant & coolant tubing | Excellent thermal conductivity |
| Petrochemical | Heat exchanger & process tubes | High-temperature resistance |
| Power Generation | Steam and condensate lines | Oxidation & scaling resistance |
Additional industry applications include: dairy processing, semiconductor manufacturing, aerospace fluid systems, shipbuilding, laboratory equipment, and pulp & paper mills.
Standards, Certifications & Quality
Applicable Standards & Specifications
- ASTM A269: Standard specification for seamless and welded austenitic stainless steel tubing for general service
- ASTM A249: Welded austenitic steel boiler, superheater, heat-exchanger and condenser tubes
- ASTM A270: Seamless and welded austenitic stainless steel sanitary tubing
- ASTM A213: Seamless ferritic and austenitic alloy-steel boiler, superheater, and heat-exchanger tubes
- ASTM A312: Seamless, welded, and heavily cold-worked austenitic stainless steel pipes
- ASME SA213 / SA249: ASME Boiler & Pressure Vessel Code equivalents
- DIN EN 10216-5: Seamless steel tubes for pressure purposes - austenitic grades
- JIS G3447 / G3463: Japanese Industrial Standards for stainless steel sanitary and heat-exchanger tubes
Quality Assurance at Metinox Overseas
- ISO 9001:2015 Quality Management System certification
- Third-party inspection available through SGS, Bureau Veritas, TUV, and Lloyd's Register
- Mill Test Certificates as per EN 10204 3.1 and 3.2
- In-house PMI (Positive Material Identification) testing
- Hydrostatic pressure testing on all pressure-bearing tubes
- Eddy current non-destructive testing (NDT) for defect detection on seamless tubes
- Dimensional inspection using digital micrometers and optical comparators
FAQs
Standard annealing is performed in an air atmosphere, which causes oxidation and leaves a dull, scaly surface. Bright annealing is carried out in a controlled, oxygen-free environment (using hydrogen or nitrogen gas), preventing oxidation entirely. The result is a smooth, reflective, mirror-like surface that requires no further pickling or passivation - making bright annealed tubes ideal for hygienic, high-purity, and precision applications.
SS 304 bright annealed tubes are processed at temperatures ranging from 1,000°C to 1,200°C (1,832°F to 2,192°F) in a controlled, inert gas atmosphere. This thermal treatment relieves internal stresses, improves ductility, enhances corrosion resistance, and produces the characteristic clean, bright surface finish.
Yes. SS 304 bright annealed tubes can be welded using TIG (GTAW) or MIG welding methods. Due to their low carbon content (max 0.08%), sensitization risk is minimized. For applications requiring repeated thermal cycles, we recommend using the low-carbon variant SS 304L for additional weld-zone protection.
Our 304 BA tubes conform to multiple ASTM standards including: ASTM A249 (welded austenitic steel boiler tubes), ASTM A269 (seamless and welded austenitic tubes for general service), ASTM A270 (sanitary tubing for food/pharma), and ASTM A213 (seamless ferritic/austenitic boiler and heat exchanger tubes)..
Metinox Overseas caters to both large-volume industrial buyers and smaller specialized requirements. Please contact our sales team to discuss your specific quantity, dimensions, and delivery requirements. We offer flexible ordering with competitive pricing for all project sizes.
Enquire Now
Get pricing within 24 hours!
