TP321 Stainless Steel Hexagonal Hollow Tube 321 Stainless Steel Hex Pipe S14 - S75mm

321 Stainless Steel Hexagonal Pipe – Technical Overview

1. Introduction

321 stainless steel hexagonal pipe is a hollow hexagonal bar made from titanium-stabilized austenitic stainless steel (321). The addition of titanium (Ti) enhances its resistance to intergranular corrosion, particularly in high-temperature environments (up to 900°C). It is widely used in aerospace, chemical processing, heat exchangers, and exhaust systems due to its excellent thermal stability and oxidation resistance.

2. Specifications

• Shape & Dimensions:

  • Hexagonal across flats (S): 6mm to 50mm

  • Wall thickness (T): 0.5mm to 5mm

  • Length: 1m to 6m (custom lengths available)

• Surface Finish: Smooth, polished, or matte finish options.

3. Standards Compliance

• International Standards:

  • ASTM A312/A269 (Seamless & Welded Pipes)

  • ASTM A554 (Welded Mechanical Tubing)

  • EN 10296-2 (European Standard)

• Chinese Standards:

  • GB/T 12770 (Welded Stainless Steel Pipes)

  • GB/T 14976 (Seamless Stainless Steel Pipes)

4. Chemical Composition (%)

Key Feature: Titanium (Ti) ≥ 5×C% prevents chromium carbide precipitation, improving high-temperature performance.

5. Mechanical Properties

Note: Retains strength at elevated temperatures (up to 900°C).

6. Manufacturing Process

1. Material Preparation: 321 stainless steel billets (with Ti stabilization).

2. Forming:

   • Seamless Pipes: Hot extrusion or cold drawing.

   • Welded Pipes: Rolled into hexagonal shape and TIG welded.

3. Heat Treatment: Solution annealing (920–1150°C) followed by rapid cooling to dissolve carbides.

4. Surface Treatment: Pickling, passivation, or polishing for corrosion resistance.

7. Key Features

✅ High-Temperature Resistance: Stable up to 900°C (avoids sensitization).
✅ Intergranular Corrosion Resistance: Titanium prevents chromium depletion.
✅ Oxidation Resistance: Forms a protective Cr₂O₃ layer in oxidizing atmospheres.
✅ Good Weldability: Suitable for welded structures.

8. Packaging

• Standard: Plastic end caps, bundled with steel straps, waterproof wrapping.

• Special: Wooden crates for heavy-duty protection.

9. Applications

• Aerospace: Jet engine components, exhaust systems.

• Chemical Industry: High-temperature pipelines, reactors.

• Heat Exchangers: Boilers, condensers.

• Automotive: Exhaust manifolds, catalytic converters.

• Architecture: Decorative structures requiring heat resistance.

Summary

321 stainless steel hexagonal pipe is ideal for high-temperature and corrosive environments, offering superior thermal stability and mechanical strength. Its titanium stabilization ensures long-term performance in critical applications.

Need customization or testing reports? Contact us for details!

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