TP321 Stainless Steel Seamless Pipe Tube / Alloy 321 SS Pipe ASTM A312 SCH40S Custom Cutting in Length Free

1. Key Technical Parameters

2. Core Performance Characteristics

• High-Temperature Stability: Titanium forms carbides (TiC) that prevent carbon from reacting with chromium (a common cause of "sensitization" in stainless steel). This ensures the pipe retains strength and corrosion resistance even when exposed to prolonged high temperatures (e.g., in furnaces or exhaust systems).
• Superior Corrosion Resistance: Unlike TP304 (a non-stabilized austenitic steel), TP321 resists intergranular corrosion—critical for applications involving welding, heat treatment, or exposure to corrosive media (e.g., nitric acid, industrial gases).
• Mechanical Durability: It offers excellent ductility and toughness at both ambient and high temperatures, making it suitable for structural components that require shape flexibility and resistance to thermal stress.
• Oxidation Resistance: The chromium-rich oxide layer on its surface provides strong protection against oxidation and scaling in high-temperature air or flue gas environments.

3. Production Process

1. Raw Material Selection: High-purity TP321 stainless steel billets (with strict compliance to chemical composition) are selected as the base material.
2. Hot Piercing: Billets are heated to 1200–1250°C and pushed through a piercing mill to create a hollow "metal tube" (known as a "mother tube").
3. Hot Rolling/Extrusion: The mother tube is further processed via hot rolling or extrusion to reduce its outer diameter and wall thickness to the target size, while maintaining seamless integrity.
4. Heat Treatment:
   • Solution Annealing: Heated to 1010–1150°C and rapidly cooled (quenched) to dissolve carbides, restore austenitic structure, and enhance corrosion resistance.
   • Stabilization Annealing: Optional (for critical applications) – heated to 850–900°C to promote titanium carbide formation, further reducing intergranular corrosion risk.
5. Cold Finishing (Optional): For applications requiring tight dimensional tolerance, the pipe undergoes cold drawing or cold rolling to refine surface finish (Ra ≤0.8 μm) and size precision.
6. Cutting & Inspection: The pipe is cut to standard lengths (6m/12m) or custom lengths (free of charge per order). It then undergoes rigorous testing:
   • Non-destructive testing (NDT): Ultrasonic testing (for internal defects) and eddy current testing (for surface defects).
   • Chemical composition analysis (via spectrometry).
   • Mechanical property testing (tensile, hardness, elongation).
   • Dimensional inspection (OD, wall thickness, straightness).

4. Compliance Standards

• Primary Standard: ASTM A312 (Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes) – the most widely recognized standard for TP321 pipes in North America and global markets.
• Dimensional Standard: ASME B36.10M (Standard for Wrought Steel and Wrought Iron Pipes) – defines wall thickness schedules (e.g., SCH40S, SCH80S) and nominal sizes.
• Other Relevant Standards:
  • EN 10216-5 (European standard for seamless stainless steel pipes for pressure purposes).
  • JIS G3459 (Japanese standard for stainless steel pipes).
  • GB/T 14976 (Chinese standard for seamless stainless steel pipes for fluid transport).

5. Competitive Advantages

• Intergranular Corrosion Resistance: Titanium stabilization eliminates "sensitization" (chromium carbide depletion at grain boundaries), a major advantage over TP304 in welded or heat-treated applications.
• Superior High-Temperature Performance: Outperforms TP304 and TP316 in continuous high-temperature service (above 600°C), as it retains strength and resists scaling better.
• Cost-Effective Alternative to High-Nickel Alloys: While TP321 has higher nickel content than TP304, it is more affordable than nickel-rich alloys (e.g., Alloy 310, Alloy 800) for high-temperature applications.
• Customization Flexibility: Free length cutting (per customer requirements) reduces on-site processing time and material waste, lowering overall project costs.
• Wide Compatibility: Complies with global standards (ASTM, EN, JIS), making it suitable for international projects and cross-border supply chains.

6. Equivalent Grades

7. Typical Applications

• Petrochemical & Chemical Industry:
  • Pipes for nitric acid production, sulfuric acid recovery, and chemical reactors.
  • Welded piping systems for corrosive fluid transport (avoids intergranular corrosion post-welding).
• Aerospace & Aviation:
  • Exhaust systems for aircraft engines (withstands continuous high temperatures up to 870°C).
  • Hydraulic lines and fuel delivery pipes in aircraft.
• Power Generation:
  • Boiler tubes, superheater tubes, and steam pipes in thermal power plants (resists oxidation and scaling).
  • Pipes for nuclear power plant secondary circuits (low carbon content reduces radiation-induced embrittlement).
• Automotive Industry:
  • Exhaust manifolds and catalytic converter pipes for high-performance vehicles (handles exhaust gas temperatures).
• Food & Pharmaceutical Industry:
  • Pipes for food processing (e.g., dairy, beverage) and pharmaceutical production (corrosion-resistant, easy to clean).
• Other Applications:
  • Heat exchanger tubes, furnace components, and industrial ovens.