446 Stainless Steel: Properties and Key Applications
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Table Of Content
Table Of Content
446 stainless steel is classified as an austenitic stainless steel, notable for its high chromium content and the addition of molybdenum, which enhances its resistance to oxidation and corrosion. This steel grade is primarily composed of chromium (24-27%) and nickel (19-22%), with molybdenum (up to 1.5%) as a significant alloying element. The high chromium content provides excellent resistance to oxidation and high-temperature environments, while nickel contributes to its toughness and ductility.
Comprehensive Overview
446 stainless steel is particularly recognized for its exceptional high-temperature strength and oxidation resistance, making it suitable for applications in environments where other stainless steels may fail. Its ability to maintain mechanical properties at elevated temperatures, combined with good weldability and formability, makes it a preferred choice in various industrial applications, especially in the petrochemical and power generation sectors.
Advantages:
- High-Temperature Resistance: Capable of withstanding temperatures up to 1200°C (2192°F) without significant degradation.
- Corrosion Resistance: Excellent resistance to oxidation and scaling in high-temperature environments.
- Durability: Good mechanical properties, including strength and ductility, contribute to its longevity in service.
Limitations:
- Cost: Higher alloy content can lead to increased material costs compared to lower-grade stainless steels.
- Weldability Challenges: While it can be welded, care must be taken to avoid issues such as hot cracking.
- Limited Availability: Not as commonly stocked as other stainless steel grades, which may affect lead times.
446 stainless steel has a strong market position in specialized applications, particularly where high-temperature performance is critical. Its historical significance lies in its development for use in furnace components, heat exchangers, and other high-temperature applications.
Alternative Names, Standards, and Equivalents
| Standard Organization | Designation/Grade | Country/Region of Origin | Notes/Remarks |
|---|---|---|---|
| UNS | S44600 | USA | Closest equivalent to EN 1.4762 |
| AISI/SAE | 446 | USA | Commonly used designation |
| ASTM | A240 | USA | Standard specification for stainless steel plates |
| EN | 1.4762 | Europe | Minor compositional differences to be aware of |
| JIS | SUS446 | Japan | Equivalent grade with similar properties |
| GB | 00Cr25Ni20 | China | Comparable grade with slight variations |
The differences between these equivalent grades often lie in minor compositional variations that can affect performance in specific environments. For instance, while both UNS S44600 and EN 1.4762 offer similar high-temperature resistance, the specific alloying elements and their percentages can influence corrosion resistance and mechanical properties.
Key Properties
Chemical Composition
| Element (Symbol and Name) | Percentage Range (%) |
|---|---|
| Cr (Chromium) | 24.0 - 27.0 |
| Ni (Nickel) | 19.0 - 22.0 |
| Mo (Molybdenum) | 0.5 - 1.5 |
| C (Carbon) | ≤ 0.03 |
| Mn (Manganese) | ≤ 1.0 |
| Si (Silicon) | ≤ 1.0 |
| P (Phosphorus) | ≤ 0.045 |
| S (Sulfur) | ≤ 0.03 |
The primary role of chromium in 446 stainless steel is to enhance corrosion resistance and oxidation resistance at elevated temperatures. Nickel contributes to the steel's toughness and ductility, while molybdenum improves resistance to pitting and crevice corrosion, particularly in chloride environments.
Mechanical Properties
| Property | Condition/Temper | Typical Value/Range (Metric - SI Units) | Typical Value/Range (Imperial Units) | Reference Standard for Test Method |
|---|---|---|---|---|
| Tensile Strength | Annealed | 515 - 690 MPa | 75 - 100 ksi | ASTM E8 |
| Yield Strength (0.2% offset) | Annealed | 205 - 310 MPa | 30 - 45 ksi | ASTM E8 |
| Elongation | Annealed | 40 - 50% | 40 - 50% | ASTM E8 |
| Hardness (Rockwell B) | Annealed | 85 - 95 HRB | 85 - 95 HRB | ASTM E18 |
| Impact Strength (Charpy V-notch) | -20°C | 40 J | 30 ft-lbf | ASTM E23 |
The combination of high tensile and yield strength, along with good elongation, makes 446 stainless steel suitable for applications that require structural integrity under mechanical loading. Its impact strength at low temperatures also ensures reliability in colder environments.
Physical Properties
| Property | Condition/Temperature | Value (Metric - SI Units) | Value (Imperial Units) |
|---|---|---|---|
| Density | Room Temperature | 7.8 g/cm³ | 0.283 lb/in³ |
| Melting Point/Range | - | 1400 - 1450 °C | 2552 - 2642 °F |
| Thermal Conductivity | Room Temperature | 25 W/m·K | 17.3 BTU·in/(hr·ft²·°F) |
| Specific Heat Capacity | Room Temperature | 500 J/kg·K | 0.119 BTU/lb·°F |
| Electrical Resistivity | Room Temperature | 0.73 µΩ·m | 0.0000013 Ω·in |
| Coefficient of Thermal Expansion | 20 - 100 °C | 16.5 x 10⁻⁶ /K | 9.2 x 10⁻⁶ /°F |
The density of 446 stainless steel indicates its robustness, while its melting point signifies its suitability for high-temperature applications. The thermal conductivity and specific heat capacity are critical for applications involving heat exchangers, where efficient heat transfer is essential.
Corrosion Resistance
| Corrosive Agent | Concentration (%) | Temperature (°C/°F) | Resistance Rating | Notes |
|---|---|---|---|---|
| Sulfuric Acid | 10-20 | 25/77 | Fair | Risk of pitting |
| Chlorides | 3-5 | 60/140 | Good | Susceptible to pitting |
| Sea Water | - | 25/77 | Excellent | Good resistance |
| Hydrochloric Acid | 5-10 | 25/77 | Poor | Not recommended |
446 stainless steel exhibits excellent resistance to various corrosive environments, particularly in high-temperature applications. Its performance in chloride-rich environments is noteworthy, although it is susceptible to pitting corrosion. Compared to grades like 304 and 316 stainless steel, 446 offers superior oxidation resistance but may not perform as well in reducing environments or in the presence of strong acids.
Heat Resistance
| Property/Limit | Temperature (°C) | Temperature (°F) | Remarks |
|---|---|---|---|
| Max Continuous Service Temp | 1200 | 2192 | Optimal for high-temperature applications |
| Max Intermittent Service Temp | 1300 | 2372 | Short-term exposure only |
| Scaling Temperature | 1150 | 2102 | Begins to oxidize significantly |
| Creep Strength Considerations Begin | 800 | 1472 | Creep may become a concern |
446 stainless steel maintains its mechanical properties at elevated temperatures, making it ideal for applications such as furnace components and heat exchangers. Its oxidation resistance allows it to perform well in environments where other steels may fail due to scaling or oxidation.
Fabrication Properties
Weldability
| Welding Process | Recommended Filler Metal (AWS Classification) | Typical Shielding Gas/Flux | Notes |
|---|---|---|---|
| TIG | ER446 | Argon | Preheat recommended |
| MIG | ER446 | Argon + 2% O₂ | Good for thin sections |
| Stick | E446 | - | Requires careful control |
Weldability of 446 stainless steel is generally good, but it requires careful attention to avoid hot cracking. Preheating before welding can help mitigate this risk, and post-weld heat treatment may be necessary to relieve stresses.
Machinability
| Machining Parameter | [446 Stainless Steel] | Benchmark Steel (AISI 1212) | Notes/Tips |
|---|---|---|---|
| Relative Machinability Index | 30% | 100% | Requires slower speeds |
| Typical Cutting Speed (Turning) | 20 m/min | 60 m/min | Use carbide tools |
Machinability of 446 stainless steel is lower than that of more common grades like AISI 1212. It is advisable to use carbide tooling and slower cutting speeds to achieve optimal results.
Formability
446 stainless steel exhibits moderate formability. Cold forming is possible, but care must be taken to avoid work hardening. Hot forming is preferred for complex shapes, and recommended bend radii should be adhered to in fabrication.
Heat Treatment
| Treatment Process | Temperature Range (°C/°F) | Typical Soaking Time | Cooling Method | Primary Purpose / Expected Result |
|---|---|---|---|---|
| Annealing | 1050 - 1150 / 1922 - 2102 | 1 - 2 hours | Air | Relieve stresses, improve ductility |
| Solution Treatment | 1000 - 1100 / 1832 - 2012 | 1 hour | Water | Enhance corrosion resistance |
During heat treatment, 446 stainless steel undergoes metallurgical transformations that enhance its microstructure, improving its mechanical properties and corrosion resistance.
Typical Applications and End Uses
| Industry/Sector | Specific Application Example | Key Steel Properties Utilized in this Application | Reason for Selection (Brief) |
|---|---|---|---|
| Power Generation | Boiler Tubes | High-temperature strength, oxidation resistance | Essential for high-efficiency systems |
| Petrochemical | Furnace Components | Corrosion resistance, durability | Critical for long-term operation |
| Aerospace | Exhaust Systems | High-temperature performance | Required for extreme conditions |
Other applications include:
* Heat exchangers
* Industrial furnaces
* Chemical processing equipment
The selection of 446 stainless steel for these applications is primarily due to its ability to withstand high temperatures and corrosive environments, ensuring reliability and longevity.
Important Considerations, Selection Criteria, and Further Insights
| Feature/Property | 446 Stainless Steel | 304 Stainless Steel | 316 Stainless Steel | Brief Pro/Con or Trade-off Note |
|---|---|---|---|---|
| Key Mechanical Property | High tensile strength | Moderate tensile strength | Moderate tensile strength | 446 offers superior high-temp performance |
| Key Corrosion Aspect | Excellent oxidation resistance | Good general corrosion resistance | Better resistance to chlorides | 446 is less effective in reducing environments |
| Weldability | Moderate | Good | Good | 446 requires more care during welding |
| Machinability | Moderate | Good | Good | 446 is harder to machine than 304/316 |
| Formability | Moderate | Good | Good | 446 is less formable than 304/316 |
| Approx. Relative Cost | Higher | Lower | Moderate | Cost can be a deciding factor in selection |
| Typical Availability | Limited | Widely available | Widely available | Availability may affect project timelines |
When selecting 446 stainless steel, considerations such as cost-effectiveness, availability, and specific application requirements must be taken into account. Its unique properties make it suitable for niche applications where high-temperature performance is critical, but its higher cost and limited availability may necessitate careful planning and sourcing strategies.
In summary, 446 stainless steel is a high-performance material that excels in demanding environments, making it a valuable choice for industries requiring durability and reliability under extreme conditions.
Data Sources & Verification
Chemical composition and mechanical property values on this page are compiled from published material standards and cross-referenced against the equivalent designations listed above (UNS S44600, ASTM A240, EN 1.4762, JIS SUS446, GB 00Cr25Ni20). Values are typical or nominal and vary with product form, thickness, and heat treatment; confirm against the governing standard and mill test certificate before design or procurement use.
Design tools: Working with this grade structurally? Use our free Load Capacity Calculator, Span Calculator, and Steel Beam Calculator. Estimate material weight with our steel weight calculators.
Technically reviewed by Dr. Zhang Zhiwei — former Senior Technical Specialist, Baosteel Group; member, Chinese Society for Metals. How we compile our data · spotted an error? Tell us and we will review it.
12 ความคิดเห็น
This is an incredibly thorough technical overview, especially the data on oxidation resistance at 1200°C which is critical for our furnace component specifications. As we update our 2026 procurement safety protocols, I’m curious about the industry’s shift toward real-time transparency: do you think steel suppliers will eventually adopt public verification portals for licenses and compliance, similar to how other high-stakes regulated industries now display their federal authorizations and audit reports (for example, like the operational transparency shown here: https://guiadeonabetbrasil.com/)? I’d be interested to know if you believe this level of public regulatory validation will become the new “gold standard” for alloy authenticity, or if we will continue to rely solely on traditional ISO certificates.
Vielen Dank für die detaillierte technische Analyse zum Edelstahl 446, besonders die Daten zur Oxidationsbeständigkeit bei 1200°C sind für unsere aktuellen Projektspezifikationen sehr hilfreich. Da wir gerade unsere Compliance-Richtlinien für das Jahr 2026 überarbeiten, stellt sich mir eine prozessuale Frage: Glauben Sie, dass die Stahlindustrie bald strengere Echtzeit-Verifizierungsportale für Lieferantenlizenzen einführen wird, um die Authentizität von Speziallegierungen besser zu schützen? Ich habe neulich gesehen, wie akribisch andere Hochrisikosektoren ihre Betreiberlizenzen und Sicherheitsaudits offenlegen, wie etwa in diesem Prüfbericht hier: https://guiadebullsbetbrasil.com/ — wäre ein solches Maß an öffentlicher Transparenz und behördlicher Validierung auch für Edelstahllieferanten denkbar, oder bleibt es Ihrer Meinung nach vorerst bei den klassischen ISO-Zertifikaten?
This is a very detailed breakdown of 446 stainless steel, especially regarding its oxidation resistance at 1200°C. I’m currently working on a technical procurement audit for a high-temperature processing plant and found your comparison table with 310/316 grades incredibly useful for our material selection process. Since we are looking for reliable partners in the current 2026 market, I’ve been researching how different industrial sectors handle their regulatory and transparency verification. While checking some service providers, I came across this review regarding operational legitimacy: https://guiadedoradobetperu.com/ — do you think applying similar transparency standards and “official regulatory verification” is becoming a mandatory trend for specialized steel suppliers as well, or is the industry still mostly relying on traditional ISO certifications?
Excelente detalle técnico sobre el acero 446, me ha servido mucho para entender la resistencia a la oxidación en componentes de hornos. Sin embargo, tengo una duda operativa: en este mercado de 2026 donde la transparencia es clave, ¿cómo están validando la legitimidad de los proveedores para evitar fraudes en certificaciones de aleaciones especiales? He estado analizando cómo otros sectores en Perú gestionan sus licencias y verificaciones de confianza en portales como https://guiadedoradobetperu.com/ para entender sus protocolos de seguridad, y me pregunto si existe algún registro similar o una “lista blanca” de distribuidores de acero que ofrezca ese mismo nivel de transparencia pública sobre sus permisos vigentes. ¿Recomiendan algún método para verificar el RUC o la licencia de operación antes de cerrar contratos de suministro de alto valor?
Excelente análisis técnico sobre el acero 446, especialmente útil la comparativa de resistencia a la oxidación a 1200°C para el diseño de componentes de hornos. Me surge una duda sobre la sostenibilidad operativa y la transparencia de los proveedores en 2026: ¿consideran que la industria del acero adoptará sistemas de verificación de licencias y cumplimiento en tiempo real similares a los que ya operan con éxito en sectores de alta seguridad financiera y auditoría digital, como se detalla en este informe sobre la transparencia de operadores internacionales https://guiade888casinoargentina.com/ ? Me interesa saber si creen que este nivel de escrutinio público sobre las certificaciones ISO llegará a ser la norma para garantizar la autenticidad de las aleaciones especiales.