446 Stainless Steel | High-Temperature Corrosion Resistance | For Industrial Furnaces

446 Stainless Steel Overview

446 is a ferritic stainless steel known for its exceptional high-temperature corrosion resistance, primarily alloyed with chromium (Cr) and aluminum (Al). It exhibits excellent oxidation resistance up to 1150°C (2100°F) and is widely used in furnace components, heat exchangers, and combustion systems. As a reliable stainless steel supplier, we offer 446 in various forms to meet your industrial needs.

Applications

• Furnace components (muffle, retorts, annealing boxes)
• Heat exchangers and boiler parts
• Combustion chambers and burner parts
• Thermocouple sheaths and kiln linings
• Automotive exhaust system components

Standards

• ASTM A276: Stainless Steel Bars and Shapes
• ASTM A314: Stainless Steel Billets and Bars for Forging
• DIN EN 10088-3: Stainless Steels - Semi-finished Products, Bars, Rods, Wire, Sections and Bright Products
• JIS G4303: Stainless Steel Bars
• GOST 5632: Stainless and Heat-Resistant Steels

Size Range & Delivery

We offer 446 stainless steel in a wide range of forms and sizes to meet diverse project requirements:

• Hot Rolled Round Bars: Φ10mm - Φ300mm
• Hot Rolled Flat Bars: Thickness 10mm - 100mm, Width 20mm - 500mm
• Forged Round Bars: Φ80mm - Φ800mm (equipped with 6000-ton forging press and radial forging machine)
• Forged Flat Bars: Thickness 50mm - 400mm, Width 100mm - 1000mm
• Steel Plates (on request): Thickness 5mm - 80mm, Width 1000mm - 2000mm

Stock & Delivery: Conventional sizes are in Ready Stock with delivery within 7 days. Custom forgings/rolled products have a minimum order quantity (MOQ) of 3 tons and delivery within 30 days. For small-batch melting, we have small furnaces supporting 3-5 tons MOQ (depending on grade). For large orders, our 30-60 ton electric arc furnace ensures fast delivery.

Chemical Composition

Melting Process

We adopt advanced melting processes to ensure the purity and quality of 446 stainless steel:

• Standard Process: EAF (Electric Arc Furnace) + LF (Ladle Furnace) + VD (Vacuum Degassing)
• High-Purity Option: Add ESR (Electroslag Remelting) or PESR (Pressurized Electroslag Remelting) for improved cleanliness and microstructure
• Ultra-High-Purity Option: VIM (Vacuum Induction Melting) + VAR (Vacuum Arc Remelting) for critical applications
• Stainless Steel Specific: AOD (Argon Oxygen Decarburization) is included to control carbon content precisely

Custom melting processes can be discussed based on your specific application requirements.

Mechanical Properties

Heat Treatment

The recommended heat treatment for 446 stainless steel is as follows:

• Annealing: Heat to 780-880°C (1435-1615°F), hold for 1-2 hours per 25mm of thickness, then air cool or furnace cool slowly. This process softens the steel, improves machinability, and relieves internal stresses.
• Stress Relieving: Heat to 600-700°C (1110-1290°F), hold for 1-2 hours, then air cool. Recommended after welding or heavy machining to reduce distortion.

Surface Finish

We offer various surface finishes to meet different application requirements:

• Black Skin (As-Rolled/Forged): Suitable for applications where surface finish is not critical. Tolerance: ±0.5mm to ±2mm depending on size.
• Turned (Peeled): For round bars. Surface roughness: Ra 6.3-12.5μm. Tolerance: h9-h11.
• Ground: For round bars requiring high precision. Surface roughness: Ra 0.8-3.2μm. Tolerance: h6-h8.
• Milled: For flat bars and forged blocks. Surface roughness: Ra 12.5-25μm. Tolerance: ±0.1mm to ±0.5mm.
• CNC Machined: Custom precision machining available. Surface roughness and tolerance as per customer drawings.

Inspection & Certification

We implement strict quality control throughout the production process to ensure every product meets your requirements:

• Pre-Production: Raw material chemical composition verification (spectrometer analysis) and forging process planning.
• In-Production: Dimensional checks, temperature monitoring during heat treatment, and intermediate ultrasonic testing (UT).
• Post-Production:
  • 100% dimensional inspection
  • Ultrasonic Testing (UT) per ASTM A388 or EN 10228 (sampling plan: 100% for critical applications, AQL 2.5 for general use)
  • Chemical composition recheck
  • Mechanical properties testing (tensile, hardness)
  • Metallographic examination (on request)
  • Corrosion testing (on request)

Certification: EN 10204 3.1 certificates are provided as standard. EN 10204 3.2 certificates (with third-party verification by SGS, TUV, etc.) are available on request. Our production system complies with ISO 9001:2015.

Packaging

We take great care in packaging to ensure your products arrive in perfect condition, even during long sea voyages:

• Black Skin Products: Steel wire捆扎 (bundled with steel wire) for stability, loaded into containers with wooden pallets or supports to prevent damage during transportation.
• Bright Surface Products (Turned/Ground/Machined):
  • Individually wrapped in anti-rust paper or plastic film
  • Protected with foam or cardboard to prevent surface scratches and damage to dimensional accuracy
  • Packed in wooden cases or crates with proper cushioning
• Rust Prevention: All products are coated with high-quality anti-rust oil before packaging to ensure no rust occurs during sea transportation. For long-term storage, additional rust protection measures can be applied on request.

FAQ