446 Stainless Steel Pipe – 1150 °C Continuous Service, 30-50% Cost Saver vs 310/309, Ultimate Scaling Resistance
Meta Description: 446 stainless steel pipe seamless/welded 25% Cr, 1150 °C scaling resistance, best 446 stainless steel pipe price from global supplier. Data sheet, specs, stock.
Introduction – Why 446 Stainless Steel Pipe Becomes the Go-To Ferritic Hero Above 1000 °C
When a cement kiln in Egypt needed radiant tubing that could survive 1120 °C flue gas for five years straight, engineers skipped 310 and specified 446 stainless steel pipe. The reason? This ferritic 446 stainless steel pipe offers the highest oxidation resistance of any ferritic grade—1150 °C continuous, 1200 °C intermittent—while costing 30-50% less than nickel-rich austenitic alternatives. With 25% chromium, the 446 stainless steel oxidation resistance pipe forms a tight Cr₂O₃ scale that regrows after spallation, giving furnace OEMs, refinery heaters and glass lehrs unprecedented uptime. Unlike 310, 446 stainless steel seamless pipe exhibits lower thermal expansion (10.4 µm/m·K), reducing thermal-fatigue cracks in cyclic duty. From schedule 40 446 stainless steel pipe in pyrolysis heaters to 8″ EFW recuperator coils, this high-temperature 446 stainless steel pipe resists sulfidation, carburization and molten chloride salts, making it the best 446 stainless steel pipe distributor choice for aggressive heat. Our company stocks 8,000+ tons, provides full 446 stainless steel pipe data sheet certifications, and guarantees the most competitive 446 stainless steel pipe price on the planet. Read the technical tables below, download the scaling curves, and discover why 446 vs 310 vs 309 stainless steel pipe comparisons always end with 446.
Product Overview & Extreme Advantages
- 1150 °C continuous scaling resistance – highest among all ferritic stainless pipes
- 25% chromium 446 pipe – self-healing Cr₂O₃ scale, weight gain <1 mg/cm² after 1,000 h at 1050 °C
- 30-50% cost saving versus 310/309, lower Ni-Mo alloy surcharge
- Fully magnetic – simplifies inspection, no sigma-phase embrittlement
- Lower thermal expansion – 30% less than 310, fewer expansion joints needed
- Good sulfidation & carburization resistance – outperforms 304H, 321 in reducing sulfur environments
- Wide inventory – 1/2″–48″ NPS, Sch 10S–XXS, seamless & welded EFW
Every heat-resistant 446 stainless steel pipe is solution-annealed, pickled, and 100% UT/RT tested before release.
Chemical Composition Table (UNS S44600)
| Element | Min % | Max % |
|---|---|---|
| Cr | 23.0 | 27.0 |
| C | – | 0.20 |
| Mn | – | 1.50 |
| Si | – | 1.00 |
| P | – | 0.040 |
| S | – | 0.030 |
| N | – | 0.25 |
| Fe | Balance | – |
Mechanical Properties Table – Annealed Condition
| Temp °C | UTS MPa | YS 0.2% MPa | Elong. % | Hardness HB |
|---|---|---|---|---|
| 20 | 515 | 310 | 20 | 170 |
| 600 | 330 | 180 | 23 | 140 |
| 800 | 180 | 90 | 30 | 100 |
| 1000 | 70 | 35 | 45 | 50 |
High-Temperature Oxidation & Scaling Resistance Table
| Exposure | Temp °C | Time h | Weight Gain mg/cm² | Max Metal Loss µm |
|---|---|---|---|---|
| Continuous | 1000 | 1000 | 0.8 | 15 |
| Continuous | 1100 | 1000 | 1.2 | 25 |
| Intermittent | 1200 | 200 | 2.1 | 40 |
446 vs 310 vs 309 vs 304H vs 321 Pipe Comparison
| Grade | Max Service °C | Creep Rupture MPa @ 900 °C | Thermal Fatigue | Cost Index | Availability |
|---|---|---|---|---|---|
| 446 pipe | 1150 | 18 | Excellent | 70 | Stock |
| 310 pipe | 1150 | 22 | Good | 100 | Limited |
| 309 pipe | 1050 | 15 | Fair | 85 | Stock |
| 304H pipe | 900 | 10 | Poor | 60 | Stock |
| 321 pipe | 900 | 9 | Poor | 65 | Stock |
Available Types & Specifications Table
| Type | Seamless / Welded | Size Range | Wall Thickness | Standards | Surface |
|---|---|---|---|---|---|
| 446 stainless steel seamless pipe | Seamless | 1/2″–24″ NPS | Sch 10S–160 | ASTM A312, A376, A268 | Pickled, shot-blasted |
| 446 stainless steel welded pipe | EFW | 24″–48″ NPS | Sch 10S–XXS | ASTM A358, A778 | Pickled, annealed |
High-Temperature Performance Guide
- Scaling curve – parabolic rate constant Kp = 1.2×10⁻¹² g²/cm⁴·s at 1100 °C
- Sulfidation – weight gain <3 mg/cm² after 100 h in 1% H₂S/Ar at 900 °C
- Carburization – carbon pickup <0.02% after 500 h in 5% CH₄/H₂ at 1000 °C
- Support spacing – max 1.2 m between hangers for 4″ Sch 40 pipe at 1000 °C to limit sag to 2 mm/m
Major Applications
- Furnace tubes, kiln tubes, radiant tubes, recuperator tubes
- Soot-blower tubes, pyrolysis coils, cement kiln inlet tubes
- Glass lehr rollers, burner nozzles, thermal oxidizer piping
- Refinery heater tubes, heat exchanger tubes in sulfuric acid plants
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Why We Are the Best 446 Stainless Steel Pipe Distributor
- Largest ex-stock holder of rare 446 stainless steel pipe – 8,000+ tons in Houston, Rotterdam, Mumbai
- Direct mill contracts, in-house solution annealing & pickling – 446 stainless steel seamless pipe ready in 72 h
- 100% ultrasonic + radiographic testing; full EN 10204 3.1/3.2, PED 2014/68/EU, NACE on request
- Precision cutting, beveling, CNC facing up to 48″ OD
- Fastest worldwide export – 5 days to US Gulf, 7 days to EU, 3 days intra-Asia
- Unbeatable 446 stainless steel pipe price – mill-direct, zero trader margin
We are the global No.1 446 stainless steel pipe supplier.
Packaging & Delivery Standards
- Heavy wooden boxes with steel cradles for OD ≤24″
- Bundle strapping ≤2 t tension, plastic end protectors
- VCI wrap + desiccant for sea freight >30 days
- Full certification package zipped & couriered
FAQ Section
Q1: Maximum continuous service temperature of 446 pipe?
A1: 1150 °C in air; 1200 °C intermittent.
Q2: Is 446 stainless steel pipe magnetic?
A2: Yes, fully ferritic and magnetic at all temperatures.
Q3: 446 vs 310 differences & cost advantage?
A3: 446 offers equal scaling resistance, 30% lower cost, lower expansion, but lower creep above 950 °C.
Q4: Can 446 pipe be welded and what filler?
A4: Use AWS A5.9 ER446 or ER310; no pre-heat, minimize heat input <15 kJ/cm.
Q5: Does 446 suffer sigma-phase embrittlement?
A5: No sigma below 600 °C; ferritic structure remains stable.
Q6: Recommended preheat & PWHT?
A6: No pre-heat; PWHT 760 °C for 10 min per 25 mm to relieve HAZ stresses.
Q7: Creep strength at 900 °C?
A7: 18 MPa for 10,000 h rupture – adequate for most furnace supports.
Q8: Minimum order quantity?
A8: 50 kg (one piece) for stocked sizes; mill orders from 500 kg.
Q9: Typical lead time for Sch 80 seamless 446 pipe?
A9: 5 days ex-stock; 3 weeks for 14″+ non-stock.
Q10: NACE compliance possible?
A10: Yes, hardness ≤22 HRC after anneal meets NACE MR0175.
Q11: Difference between 446 and 310 in sulfidation environments?
A11: 446 forms Cr₂O₃ faster, resisting low-oxygen sulfidation; 310 may suffer nickel sulfide penetration.
Conclusion – Request Your 446 Stainless Steel Pipe Quote Now
Stop paying 310 prices for 1150 °C service. Our 446 stainless steel pipe delivers the highest scaling resistance, lowest thermal expansion and 30–50% cost saving versus austenitic grades. With 8,000 tons in stock, full PED certification and 48-hour processing, we are the best 446 stainless steel pipe distributor on the globe. Email, WhatsApp, WeChat, phone or live chat 24/7—send your specs and receive an unbeatable 446 stainless steel pipe price quotation within 1 hour. Let’s put ultimate heat resistance into your next project today!