Information on annealed and pickled U-shaped tubes made from cold-rolled 600 and 601 nickel alloys
Information on annealed and pickled U-shaped tubes made from cold-rolled 600 and 601 nickel alloys
Annealed and pickled cold-rolled Inconel 600 and 601 U-tubes are high-performance nickel alloys suitable for high-temperature and corrosive environments (such as heat exchangers and chemical processing). They offer excellent corrosion resistance (600 alloy resists chloride stress corrosion cracking, and 601 alloy resists oxidation/carburization), high strength after cold working, and good formability. Annealing softens the material, facilitating U-bending, while pickling removes surface scale, resulting in a clean surface. This makes them an ideal choice for demanding industrial heat transfer applications.
What are the casting equivalent materials for Inconel 600?
Inconel 600 (equivalent to UNS N06600) is a high-strength nickel-chromium alloy. It is known for its good corrosion resistance, high strength, and excellent performance at extreme temperatures. This alloy contains not only nickel and chromium but also iron and many other different components.
Inconel 600 cold-rolled, annealed, and pickled U-shaped tubes are high-performance nickel-chromium-iron alloy tubes with a special shape, processed through cold rolling, annealing heat treatment, and pickling surface treatment. The core process involves cold rolling to improve dimensional accuracy and surface finish, followed by annealing to relieve stress, restore material plasticity, and optimize its high-temperature oxidation resistance (up to approximately 1150°C) and resistance to chloride stress corrosion cracking. Finally, pickling removes scale and passivates the surface. These U-shaped tubes are specifically designed for corrosion-resistant, high-temperature heat transfer components requiring complex bending shapes in compact heat exchangers (such as shell-and-tube heat exchangers, boilers), high-temperature furnace tubes, and chemical reactors. They represent a top-tier tubing solution that combines precise forming, excellent performance, and reliable service.
Inconel 601 cold-rolled, annealed, and pickled U-shaped tubes are special U-shaped tubes processed using cold rolling, annealing, and pickling techniques. The core process involves cold rolling to ensure dimensional accuracy and surface finish, followed by annealing to restore material plasticity and maximize its superior oxidation resistance, carburization resistance, and high-temperature sulfidation resistance at temperatures up to approximately 1250°C. Finally, pickling achieves a clean and passivated surface. This tubing is specifically designed for extreme conditions in high-temperature heat treatment furnaces, industrial combustion systems, petrochemical cracking units, and aerospace hot-end components that require compact U-shaped bends and must withstand severe oxidation-reduction atmospheres, thermal cycling, and high-temperature corrosion over extended periods. It is a critical tubing solution for ultra-high temperature complex heat exchange and structural applications.
Comparison of chemical composition between Inconel 600 cold-rolled U-tubes and Inconel 601 annealed and pickled U-tubes:
| Element | Inconel 600 (Cold-rolled, Annealed & Pickled U-tube) | Inconel 601 (Cold-rolled, Annealed & Pickled U-tube) |
|---|---|---|
| Nickel (Ni) | ≥ 72.0 % | 58.0 – 63.0 % |
| Chromium (Cr) | 14.0 – 17.0 % | 21.0 – 25.0 % |
| Iron (Fe) | 6.0 – 10.0 % | Balance |
| Aluminum (Al) | – | 1.0 – 1.7 % |
| Carbon (C) | ≤ 0.15 % | ≤ 0.10 % |
| Manganese (Mn) | ≤ 1.0 % | ≤ 1.0 % |
| Silicon (Si) | ≤ 0.5 % | ≤ 0.5 % |
| Copper (Cu) | ≤ 0.5 % | ≤ 1.0 % |
| Titanium (Ti) | – | ≤ 0.15 % |
| Sulfur (S) | ≤ 0.015 % | ≤ 0.015 % |
Comparison table of mechanical properties between annealed Inconel 600 U-tubes and pickled Inconel 601 U-tubes:
| Property | Inconel 600 (Cold-rolled, Annealed & Pickled U-tube) | Inconel 601 (Cold-rolled, Annealed & Pickled U-tube) |
|---|---|---|
| Tensile Strength (MPa, min) | 550 – 690 | 655 – 895 |
| Yield Strength (0.2% Offset, MPa, min) | 240 | 345 |
| Elongation (% in 50 mm, min) | 30 | 30 |
| Hardness (Rockwell B, max) | 90 HRB | 95 HRB |
| High-Temperature Strength | Good strength up to ~700°C | Superior strength and oxidation resistance above 1000°C |
| Fatigue Strength | Moderate | Good, especially under thermal cycling |
U-tube Annealing and Pickling (A&P) Process
Cold Rolling: Provides initial strength and forms the tube shape.
Annealing: A heat treatment process that softens the alloy, relieves stresses caused by cold working, and improves ductility, allowing it to be bent into a U-shape without cracking.
Pickling: An acid treatment process that removes the black oxide scale formed during annealing and welding, leaving a clean, matte surface and enhancing corrosion resistance.
U-shape: Formed after annealing, crucial for compact heat exchanger designs (e.g., boiler/superheater tubes).
Why Choose Gnee as Your Nickel-Based Alloy Supplier
✅ Over 18 years of export experience, products sold to more than 80 countries
✅ Certified by ISO, SGS, and BV
✅ Global inventory of Inconel, Hastelloy, Incoloy, and Monel alloy tubing, plates, and bars
✅ Custom processing services available – including cutting, polishing, CNC machining, and packaging
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📦 Packaging and Shipping
All stainless steel products are packaged using the following methods:
Wooden pallets or crates
Moisture-proof packaging
Labels with furnace number, standard, and size labels
Shipped worldwide by sea, air, or express
Gnee Steel is a supplier of inconel 600 alloy, offering a wide range of products including: seamless pipe (sizes: 4-219 mm; thickness: 0.5-20 mm); welded pipe (sizes: 5.0-1219.2 mm; thickness: 0.5-20 mm); plates (thickness: 0.1 to 100 mm; width: 10-2500 mm); strips; alloy round bars (diameter: 3-800 mm); flat bars (thickness: 2-100 mm; width: 10-500 mm); hexagonal bars (size: 2-100 mm); wire rods; and extruded profiles. We collaborate with steel mills to provide our customers with inconel 600 alloy products that meet or exceed numerous leading industry standards, including ASTM, ASME, SAE, AMS, ISO, DIN, EN, and BS standards.
Gnee Steel stocks and sells inconel 600, pipes, plates, strips, round bars, flat bars, forged billets, hexagonal steel, wire rods, and extruded profiles. Please feel free to contact us at ss@gneesteel.com for a quote.
