321 pickled annealed seamless pipe for boiler superheater
321 stainless steel tubing is well-suited for boiler superheaters due to its titanium alloy stability. It offers excellent high-temperature strength, resistance to intergranular corrosion, and weldability up to 899°C (1650°F). It also has good creep and oxidation resistance, making it suitable for hydronic heating and cooling applications and ideal for high-temperature environments such as boilers and exhaust systems. The "pickling annealing" process ensures a clean, smooth, and corrosion-resistant surface after manufacturing.
What is 321 stainless steel used for?
Type 321 stainless steel is ideal for heat-resistant applications. It can be used in applications up to 900°C, while Type 304 stainless steel typically has a maximum service temperature of 500°C. Type 321 stainless steel offers excellent forming and welding properties. However, due to its poor polishing properties, it is not suitable for decorative applications.
pecification Of 321 Stainless Steel Boiler Tube
| Boiler Tube Standard | ASTM A269, A249, A511, A554 / ASME SA269, SA249, SA511, SA554 |
| Boiler Tube Dimension | ANSI/ASME B36.19M, ANSI/ASME B36.10M |
| Seamless Boiler Tube Sizes | 1 / 2" NB - 16" NB |
| Welded Boiler Tube Sizes | 1 / 2" NB - 24" NB |
| Boiler Tube Outside Diameter | 6.00 mm OD up to 914.4 mm OD, Sizes up to 24" NB available Ex-stock, OD Size Steel Boiler Tubes available Ex-stock |
| Boiler Tube Manufacturing Process | Seamless / Welded / ERW / Fabricated / CDW / 100% X Ray Welded |
| Stainless Steel Boiler Tube Schedule | SCH 5, SCH10, SCH 40, SCH 80, SCH 80S, SCH 160, SCH XXS, SCH XS |
| Boiler Tube Length | Single Random, Double Random, Standard & Cut length |
321 pickled annealed seamless pipe for boiler superheater Specifications
| Stainless Steel SS 321 / 321H | |
| AISI | 321 / 321H |
| UNS | S32100 / S32109 |
| Werkstoff Nr. | 1.4541 / 1.4878 |
321 pickled annealed seamless pipe for boiler superheater Mechanical & Physical Properties
| Density | 8.0 g/cm3 |
| Melting Point | 1454 °C (2650 °F) |
| Tensile Strength | Psi – 75000 , MPa – 515 |
| Yield Strength (0.2%Offset) | Psi – 30000 , MPa – 205 |
| Elongation | 35% |
Why 321 Steel is Suitable for Boiler Superheaters:
Titanium Alloy Stability: The addition of titanium prevents carbide precipitation, especially in the heat-affected zone of welds, eliminating the risk of intergranular corrosion.
High-Temperature Stability: 321 steel resists oxidation and maintains its strength even at temperatures up to 899°C (1650°F).
Corrosion and Oxidation Resistance: It offers excellent resistance to aqueous corrosion and hot gas oxidation, which is critical in boiler environments.
Excellent Weldability: Titanium alloys can be used to manufacture complex components without the need for post-weld annealing to restore corrosion resistance.
Creep and Stress-Rupture Strength: It performs well under sustained high temperatures, ensuring structural integrity.
Mechanical Properties: These pipes are strong, durable, and ductile, and can be manufactured as seamless or welded pipes. Seamless pipe construction offers high precision for smaller pipe sizes.
Purpose of "Pickling and Annealing" (P&A):
Annealing: Rapid cooling after high-temperature heat treatment improves pipe strength and corrosion resistance. Pickling: This pickling process removes surface scale or impurities formed during high temperature processing, resulting in a clean, smooth, corrosion-resistant surface.
Gnee Steel specializes in the production and sale of a wide range of stainless steel products, including 304, 316, 321, 904, 904L, 2205 Duplex, 2205 Duplex, and 316L stainless steel. Gnee Steel's products are widely used in the kitchen, aerospace, chemical, power, automotive, and nuclear energy sectors. We also provide custom stainless steel solutions tailored to customer needs. For stainless steel pricing or custom alloy solutions, please email ru@gneesteelgroup.com for a quote.
