Stainless steels come in many grades, each engineered to offer specific performance features. Among them, 440C stainless steel stands out as a high-carbon, high-chromium martensitic stainless steel known for its excellent hardness, wear resistance, and corrosion resistance. It is widely used in high-performance applications where edge retention, strength, and durability are critical.
We explore the characteristics, mechanical properties, and typical uses of 440C stainless steel. Whether you’re involved in industrial design, manufacturing, tooling, or medical device production, this article will provide valuable insights into why 440C stainless steel is a popular choice for demanding applications.
At sakysteel, we specialize in supplying premium-quality 440C stainless steel in a variety of forms and sizes, meeting the needs of industries worldwide. Contact sakysteel for expert support, reliable sourcing, and tailored material solutions.
1. What is 440C Stainless Steel?
440C stainless steel is a martensitic stainless steel alloy with high levels of carbon and chromium. It is part of the 400 series and is the most corrosion-resistant grade among the 440 stainless steels (440A, 440B, and 440C).
Standard Composition of 440C:
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Carbon (C): 0.95% – 1.20%
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Chromium (Cr): 16.0% – 18.0%
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Manganese (Mn): ≤ 1.0%
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Silicon (Si): ≤ 1.0%
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Molybdenum (Mo): Optional in some versions for added toughness
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Nickel (Ni): Trace amounts
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Iron (Fe): Balance
This composition allows 440C to reach high hardness (up to 60 HRC) when heat-treated, while still providing decent corrosion resistance.
2. Key Characteristics of 440C Stainless Steel
a) High Hardness and Strength
When properly heat-treated, 440C can achieve Rockwell hardness levels between 58 to 60 HRC, making it one of the hardest stainless steels available. This makes it suitable for:
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Cutting tools
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Bearing components
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Precision parts
b) Excellent Wear and Abrasion Resistance
Due to its high carbon content, 440C demonstrates outstanding resistance to surface wear, edge deformation, and mechanical fatigue — ideal for sliding or rotating applications.
c) Good Corrosion Resistance
Although not as corrosion-resistant as 300 series stainless steels, 440C performs well in mild to moderate corrosive environments. It can resist:
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Moisture
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Food acids
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Mild chemicals
However, it is not recommended for marine or high-chloride applications without proper surface treatment.
d) Magnetic and Heat-Treatable
440C is magnetic in all conditions and can be hardened through standard heat treatment, making it easy to adapt for various mechanical and structural applications.
3. Mechanical Properties of 440C
| Property | Value (Typical, Hardened Condition) |
|---|---|
| Tensile Strength | 760 – 1970 MPa |
| Yield Strength | 450 – 1860 MPa |
| Elongation at Break | 10 – 15% |
| Hardness (Rockwell HRC) | 58 – 60 |
| Modulus of Elasticity | ~200 GPa |
| Density | 7.8 g/cm³ |
These values can vary depending on heat treatment and manufacturing process.
4. Heat Treatment Process
The performance of 440C stainless steel is greatly enhanced through heat treatment. The process generally includes:
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Hardening: Heating to 1010–1065°C (1850–1950°F)
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Quenching: Oil or air quench to harden the material
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Tempering: Typically tempered at 150–370°C (300–700°F) to reduce brittleness and increase toughness
Heat-treated 440C shows maximum hardness and excellent mechanical strength, which is crucial for precision tools and cutting edges.
5. Common Applications of 440C Stainless Steel
Due to its unique balance of hardness, wear resistance, and moderate corrosion resistance, 440C is found in a wide variety of demanding applications:
a) Cutting Tools
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Surgical blades
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Razor blades
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Industrial knives
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Scissors
b) Bearings and Valve Components
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Ball bearings
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Valve seats and stems
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Needle roller bearings
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Pivot pins
c) Aerospace and Defense
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Aircraft actuator parts
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Structural pins
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Ammunition and firearm components
d) Medical Instruments
440C’s biocompatibility and ability to maintain sharp edges make it suitable for:
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Dental tools
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Surgical instruments
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Orthopedic implants (non-permanent)
e) Mold and Die Industry
Its resistance to wear makes it suitable for:
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Plastic injection molds
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Forming dies
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Tooling components
sakysteel offers 440C stainless steel in sheets, plates, rods, and bars for these and other applications. With full traceability and quality assurance, sakysteel ensures high performance for critical projects.
6. Limitations of 440C Stainless Steel
While 440C is a high-performance material, it is not ideal for every situation:
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Corrosion resistance is limited in marine or chloride-rich environments
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Lower toughness compared to austenitic grades
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May become brittle at very high hardness unless carefully tempered
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Machining can be difficult in hardened state
For applications requiring higher ductility or corrosion resistance, 316 or duplex stainless steels may be better alternatives.
7. Surface Finishing Options
440C stainless steel can be supplied in various surface finishes, depending on end-use requirements:
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Annealed: For easy machining and forming before hardening
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Ground or polished: For aesthetic or functional precision
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Hardened and tempered: For tools and wear applications
At sakysteel, we provide customized surface finishes and dimensions for 440C stainless steel to suit client needs.
8. 440C vs Other Stainless Steels
| Grade | Hardness | Corrosion Resistance | Applications |
|---|---|---|---|
| 304 | Low | Excellent | General structural use |
| 316 | Low | Superior | Marine, food, pharma |
| 410 | Moderate | Moderate | Basic tools, fasteners |
| 440C | High | Moderate | Precision tools, bearings |
440C is the hardest and most wear-resistant among these, though with slightly lower corrosion resistance.
Conclusion
440C stainless steel is a top-tier choice when exceptional hardness, wear resistance, and moderate corrosion resistance are required. It is widely used in industries ranging from aerospace and automotive to medical and tooling. Its ability to be hardened to extreme levels while maintaining reasonable corrosion protection makes it one of the most versatile martensitic stainless steels available.
Understanding its characteristics allows engineers and buyers to make the best material selection for long-lasting, high-performance applications.
For high-quality 440C stainless steel with full certifications and value-added services like custom cutting, polishing, and heat treatment, sakysteel is your trusted supplier. Contact sakysteel today to get a quote or discuss your project requirements.
Post time: Jul-28-2025