In high temperature and corrosive environments, choosing the right material is critical. Today, we will take a deep look at a “hero behind the scenes” that performs well in such harsh conditions – 446 stainless steel (UNS S44600).
If you are looking for materials for your kiln, heat treatment equipment, or any project that requires structural stability at temperatures up to 1100°C, this article is for you. We will fully analyze the performance, core advantages, and practical applications of 446 stainless steel, and compare it with common stainless steels such as 304 and 316 to help you make the most informed decision.
What is 446 stainless steel?
446 stainless steel is a high chromium (23%-27%) ferritic stainless steel. Unlike the well-known 304 (austenitic), it cannot be hardened by heat treatment. Its high chromium content gives it unparalleled high temperature oxidation resistance and excellent resistance to sulfidation corrosion, making it one of the preferred materials in high temperature applications.
| Key Characteristics | Description |
|---|---|
| Grade/Standard | UNS S44600, ASTM A240, AISI 446 |
| Material Category | Ferritic Stainless Steel |
| Core Advantages | Excellent high-temperature oxidation resistance, outstanding resistance to sulfidation corrosion |
| Common Forms | Sheet, Coil, Bar, Tube |
The core advantages of 446 stainless steel
1. Excellent High Temperature Resistance and Oxidation Resistance
This is the most shining label of 446 stainless steel. It can maintain excellent resistance to oxide scale peeling at intermittent working temperatures up to 1100°C (2012°F) and continuous working temperatures up to 1093°C (2000°F). This makes it an irreplaceable advantage in manufacturing equipment parts that need to withstand high temperature “baking” for a long time.
2. Excellent Resistance to Sulfidation Corrosion
In many industrial environments, in addition to high temperatures, materials are also subject to corrosion from sulfur-containing gases. With its high chromium content, 446 stainless steel can effectively resist the erosion of sulfidation environments, which is particularly important in applications such as coal-fired or oil-fired combustion chambers and flues.
3. Good Thermal Conductivity and Low Thermal Expansion Coefficient
Compared with austenitic stainless steel (such as 304), 446 stainless steel has higher thermal conductivity and a lower thermal expansion coefficient. This means that it conducts heat more efficiently when the temperature changes dramatically, and the deformation stress caused by thermal expansion and contraction is smaller, which improves the thermal stability and service life of the equipment.
4. Mechanical Performance Limitations that need to be noted
No one is perfect. We also need to point out frankly that 446 stainless steel has low toughness and brittle texture at room temperature, which makes it unsuitable for structural parts that need to withstand high impact loads or complex cold forming. Its advantages are fully reflected in high temperature performance.
446 stainless steel Data Sheet
Summary
Compared with 445, it has high Cr, low carbon, and added Mo to ensure high corrosion resistance.
Features
1) High corrosion resistance;
2) Weather resistance;
3) High strength;
4) Magnetic;
5) Cannot be hardened by heat treatment.
AISI 446 Stainless Steel Chemical Composition
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.20 |
| Manganese (Mn) | ≤ 1.50 |
| Silicon (Si) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 23.00 – 27.00 |
| Nitrogen (N) | ≤ 0.25 |
Performance
Grade | YS（MPa） | TS（MPa） | EL | HV |
446 | 335 | 538 | 30 | 167 |
AISI 446 Stainless Steel Physical Properties
| Property | Value |
|---|---|
| Density | 7.65 g/cm³ |
| Melting Point | 1425 – 1510 °C |
| Thermal Conductivity | 21.6 W/m·K at 100 °C |
| Modulus of Elasticity | 200 GPa |
| Electrical Resistivity | 0.64 µΩ·m |
Use Status
Annealing and solid solution state:
2D, 2B, and other surface treatment states.
Heat Treatment
- Melting point:1425~1510℃;
- Solution treatment: 760~830℃.
Main application areas of 446 stainless steel
With its unique high temperature performance, the use of 446 stainless steel is very clear and professional. If you are in the following industries, it is likely to be the solution you are looking for:
- Heat treatment industry: annealing box, quenching basket, kiln lining, furnace roller, thermocouple protection tube.
- Glass manufacturing: glass mold, blowpipe.
- Power and energy: combustion chamber parts, boiler baffles, industrial nozzles, flue baffles.
- Petrochemical industry: oil burner parts, heat exchanger tubes.
Is your project related to this? If you are looking for reliable 446 stainless steel materials for the above applications, contact our engineers directly.
As a leading supplier of high-quality stainless steel, Huaxiao Metal offers a comprehensive product line, including 446 stainless steel. We can provide stainless steel in various forms, including sheet, coil, bar, and tube, tailored to your specific project needs.
Ready to get started?
Contact us today for a free quote! Our team of experts is ready to provide expert consultation and help you find the best stainless steel solution for your application.
446 Stainless Steel vs. Common Stainless Steels (304/316)
Many customers will ask: “What is the difference between 446 and the commonly used 304/316?” The following table is clear at a glance:
| Property | 446 Stainless Steel | 304 Stainless Steel | 316 Stainless Steel |
|---|---|---|---|
| Heat Resistance | Excellent (up to 1100°C) | Good (around 870°C) | Very Good (around 925°C) |
| Room Temperature Toughness | Low, relatively brittle | Excellent | Excellent |
| Corrosion Resistance | Good general resistance, excellent sulfur resistance | Good, but not chloride-resistant | Excellent, resistant to chlorides |
| Weldability | Fair (requires preheating and post-weld treatment) | Excellent | Excellent |
| Magnetism | Magnetic | Non-magnetic | Non-magnetic |
| Cost | Moderate | Lower | Higher |
Simple summary: If your primary consideration is extreme heat resistance, choose 446; if you need comprehensive corrosion resistance and processability at room or medium temperatures, choose 304 or 316.
FAQ
What temperature is 446 suitable for?
It can usually be used stably for a long time between 1000~1100°C, which is better than 430 and 304 stainless steel.
Can 446 replace 316 Stainless Steel?
In high temperature environments without strong acid corrosion requirements, 446 can be used as a low-nickel alternative to 316, and it has more cost advantages.
Is 446 magnetic stainless steel?
Yes, 446 is a ferrite structure with certain magnetism.
Will 446 stainless steel rust?
Although 446 stainless steel has extremely high corrosion resistance, it may still corrode in extremely harsh environments (such as high concentration hydrochloric acid environments). Under normal atmospheric environment and seawater spray conditions, its corrosion resistance far exceeds that of 304 stainless steel.
How to weld 446 stainless steel?
Recommended welding methods:
- TIG welding: most commonly used, using 446 special welding wire
- MIG welding: suitable for thick plates
- Resistance welding: suitable for thin plate connections
- Key points of welding:
- Keep low heat input
- Use pure argon shielding gas
- Stabilization treatment is recommended after welding
Can 446 stainless steel be used for food contact?
446 stainless steel does not contain nickel and meets the safety standards for food contact materials. It is often used in non-direct contact parts of food processing equipment. However, 316L stainless steel is recommended for direct contact with acidic foods.
Machining and Welding Recommendations
Machining: Due to its brittleness, machining of 446 stainless steel requires the use of rigid equipment with slow speeds and high feeds.
Welding: Welding 446 stainless steel is entirely feasible, but to prevent weld cracking, it is strongly recommended to:
- Preheat the weld area to 150-200°C.
- Use an austenitic filler metal such as AWS E310 or E312.
- Anneal immediately after welding at 815-870°C to restore toughness.
Choose the most suitable 446 stainless steel product for your project
Now you have a comprehensive understanding of 446 stainless steel. As a professional supplier, Huaxiao Stainless Steel not only provides high-quality raw materials, but also is committed to providing you with a one-stop solution.
Need to purchase 446 stainless steel plates, bars or pipes?
We at Huaxiao Stainless Steel provide 446 stainless steel materials of various specifications, and can provide customized processing services such as laser cutting and bending according to your drawings. Our team of experts is always ready to provide you with free technical consultation and competitive quotations.
Don’t worry about selecting materials for high-temperature applications anymore!
