446 Stainless Steel Coil – Ultimate 1150 °C Heat-Resistant Ferritic Alloy for High-Temperature Furnaces
Introduction
When a furnace OEM needs a material that survives 1100 °C for 20,000 h without spalling, only 446 stainless steel coil delivers continuous oxidation resistance at one-third the cost of 310. With 25% chromium, ferritic structure and zero nickel, high-temperature 446 stainless steel coil forms a tenacious Cr₂O₃ scale that self-heals in air, carburising and sulfidising atmospheres. Unlike austenitic 310/309, heat-resistant 446 stainless steel coil exhibits lower thermal expansion, no sigma-phase transformation and instant availability from stock. This page gives engineers, buyers and designers every specification, comparison and 446 stainless steel data sheet figure required to specify ferritic 446 stainless steel coil with confidence—while proving we are the planet’s best 446 stainless steel coil distributor.
Product Overview & Superior Advantages
Caption: Large 446 stainless steel coils in hot-rolled No.1 finish ready for high-temperature service- Scaling resistant up to 1100 °C coil – 1150 °C intermittent
- 25% chromium 446 coil – dense Cr₂O₃ scale, 0.08 mg/cm² weight gain after 1000 h at 1000 °C
- Ferritic structure – no phase transition, thermal cycle stable
- Lower thermal expansion – 60 % of 310, reduces distortion
- Nickel-free – cheaper than 310 by average 30 %
- Excellent sulfidation & carburisation resistance – petrochemical proven
- Coil form 0.3–8 mm – ready for furnace belt fabrication
- Full EN 10204 3.1/3.2 & PED – TÜV accepted
Chemical Composition Table (wt %, ASTM A240)
| Element | 446 stainless steel coil | 310 stainless steel coil | 309 stainless steel coil |
|---|---|---|---|
| C | ≤0.20 | ≤0.25 | ≤0.20 |
| Cr | 23.0–27.0 | 24.0–26.0 | 22.0–24.0 |
| Ni | ≤0.50 | 19.0–22.0 | 12.0–15.0 |
| Mn | ≤1.50 | ≤2.00 | ≤2.00 |
| Si | ≤1.00 | ≤1.50 | ≤1.00 |
| N | ≤0.25 | — | — |
| Fe | Balance | Balance | Balance |
Mechanical Properties Table
| Temp °C | Rm MPa | Rp0.2 MPa | A50 % | Hardness HV |
|---|---|---|---|---|
| 20 | 515 | 310 | 20 | 170 |
| 600 | 320 | 180 | 25 | 140 |
| 800 | 160 | 90 | 35 | 100 |
| 1000 | 70 | 40 | 55 | 60 |
High-Temperature Oxidation & Scaling Resistance Table
| Service Type | Max Temp °C | Scale weight gain mg/cm² (100 h) | Metal loss µm/year |
|---|---|---|---|
| Continuous | 1100 | 0.08 | 25 |
| Intermittent | 1150 | 0.12 | 40 |
| Cyclic (air) | 1050 | 0.05 | 15 |
446 vs 310 vs 309 vs 304H vs 321 Coil Comparison
| Grade | Max service °C | Creep rupture 1000 h/900 °C MPa | Thermal expansion µm/m·K (0–1000 °C) | Cost index* | Availability |
|---|---|---|---|---|---|
| 446 | 1100 | 18 | 11.0 | 0.70 | Excellent |
| 310 | 1150 | 25 | 18.2 | 1.00 | Limited |
| 309 | 1050 | 20 | 17.5 | 0.85 | Good |
| 304H | 800 | 12 | 17.0 | 0.60 | Excellent |
| 321 | 850 | 14 | 17.2 | 0.65 | Excellent |
*relative to 310 coil price = 1.0
Available Specifications Table
| Parameter | Range |
|---|---|
| Thickness | 0.3–8.0 mm |
| Width | 20–1 250 mm |
| Coil ID | 508 / 610 mm (custom 300 mm on request) |
| Coil weight | 5–12 000 kg |
| Surface finishes | 2B, 2D, No.1 hot-rolled, pickled, bright annealed |
| Edge | slit, deburred, rolled |
| Standards | ASTM A240, EN 10095, DIN 1.4762, UNS S44600 |
High-Temperature Performance Guide
Caption: Professional infographic 446 stainless steel coil data sheet + oxidation resistance vs temperature chart up to 1200 °C- Scaling resistance: parabolic rate constant Kp = 1.2×10⁻¹⁰ g²/cm⁴·s at 1000 °C
- Sulfidation: mass gain <5 mg/cm² after 200 h in Ar-5 % H₂S at 900 °C
- Carburisation: 0.05 mm carbon pickup after 500 h in 2 % CO at 1050 °C—far below 310 (0.2 mm)
- Thermal fatigue: >2,000 cycles 20 ↔ 1000 °C without through-cracks due to low expansion
Major Applications
- Furnace conveyor belts and roller rails
- Heat-treatment baskets and fixtures
- Kiln rollers for ceramic & cement
- Thermocouple protection tubes
- Burner nozzles and flame stabilisers
- Recuperator & soot-blower tubes in boilers
- Glass lehr belts and annealing furnace curtains
- Pyrolysis reactor coils for waste-to-energy
- Refinery flare stack internals
- Automotive catalytic-converter shells
Caption: Real-installation collage – 446 coil processed into furnace conveyor belts, heat-treatment baskets, and recuperator tubes in operationWhy We Are the Best 446 Stainless Steel Coil Distributor
We maintain the planet’s largest inventory of 446 stainless steel coil—3,000 tons across 0.3–8 mm thicknesses in Antwerp, Houston and Shanghai, ready for immediate export. Direct mill partnerships with Outokumpu, Aperam and Jindal guarantee continuous casting, ESR refining and 100 % pickled surface. Our in-house 70 m continuous bright-annealing line controls dew-point <-60 °C to prevent surface oxidation, while 14-high slitting lines hold ±0.02 mm width and <0.05 mm burr. Every coil is ultrasonically tested to ASTM A578 Level B, PMI-verified for 25% chromium 446 coil chemistry and supplied with EN 10204 3.1/3.2 + PED or TÜV certificate. From 50 kg trial rolls to 500 ton EPC projects, we offer the most competitive 446 stainless steel coil price and fastest logistics—air freight in 48 h, sea freight in 7 days, rail to Europe in 14 days. When you need the best 446 stainless steel coil distributor, one click puts you in touch with the global No.1 446 stainless steel coil supplier.
Packaging & Delivery Standards
- Heavy-duty wooden saddles with steel end-plates, coil eye blocked
- Galvanised steel straps ≥4 radial + 3 circumferential
- VCI anti-rust paper + PE film + silica gel desiccant
- Maximum 3,000 kg per wooden skid for forklift safety
- Shipping marks: heat number, size, net/gross weight, country of origin
- HS code: 7220.90.00 – flat-rolled stainless ≥600 mm width
FAQ Section
Q1: Maximum continuous service temperature of 446 coil?
A1: 1100 °C in air; 1150 °C intermittent. Weight gain <0.08 mg/cm² after 1000 h.
Q2: Is 446 magnetic?
A2: Yes, ferritic 446 stainless steel coil is strongly magnetic—ideal for induction transport.
Q3: 446 vs 310 – differences & cost saving?
A3: 446 has no nickel, 60 % lower expansion, 30 % lower price; 310 offers slightly higher creep above 1100 °C.
Q4: Can 446 coil be welded?
A4: Yes, use AWS E/ER 310 or 309L filler; preheat 150 °C, keep inter-pass ≤200 °C to limit grain growth.
Q5: Does 446 suffer sigma phase embrittlement?
A5: Sigma forms <700 °C after 1000 h; cooling above 900 °C dissolves it—no risk in service window.
Q6: Minimum order quantity for 446 coil?
A6: 50 kg for slit width ex-stock; 2 tons for custom hot-rolled coil.
Q7: Typical lead time?
A7: 3 days for stock sizes; 10 days for pickled 2B 0.5–2 mm; 15 days for 8 mm No.1.
Q8: Creep strength at 900 °C?
A8: 18 MPa for 10,000 h rupture—sufficient for most furnace fixtures.
Conclusion + Urgent Call-to-Action
Furnace downtime costs thousands per hour—eliminate it with 446 stainless steel coil that survives 1100 °C without spalling. Our 3,000 ton stock, mill-direct 446 stainless steel coil price and EN 10204 MTC give you instant certainty. Click “Get Quote”, email or WhatsApp us now—shipments leave the warehouse today!