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.
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).
Carbon (C): 0.95% – 1.20%
Chromium (Cr): 16.0% – 18.0%
Manganese (Mn): ≤ 1.0%
Silicon (Si): ≤ 1.0%
Molybdenum (Mo): Optional in some versions for added toughness
Nickel (Ni): Trace amounts
Iron (Fe): Balance
This composition allows 440C to reach high hardness (up to 60 HRC) when heat-treated, while still providing decent corrosion resistance.
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:
Cutting tools
Bearing components
Precision parts
Due to its high carbon content, 440C demonstrates outstanding resistance to surface wear, edge deformation, and mechanical fatigue — ideal for sliding or rotating applications.
Although not as corrosion-resistant as 300 series stainless steels, 440C performs well in mild to moderate corrosive environments. It can resist:
Moisture
Food acids
Mild chemicals
However, it is not recommended for marine or high-chloride applications without proper surface treatment.
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.
| 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.
The performance of 440C stainless steel is greatly enhanced through heat treatment. The process generally includes:
Hardening: Heating to 1010–1065°C (1850–1950°F)
Quenching: Oil or air quench to harden the material
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.
Due to its unique balance of hardness, wear resistance, and moderate corrosion resistance, 440C is found in a wide variety of demanding applications:
Surgical blades
Razor blades
Industrial knives
Scissors
Ball bearings
Valve seats and stems
Needle roller bearings
Pivot pins
Aircraft actuator parts
Structural pins
Ammunition and firearm components
440C’s biocompatibility and ability to maintain sharp edges make it suitable for:
Dental tools
Surgical instruments
Orthopedic implants (non-permanent)
Its resistance to wear makes it suitable for:
Plastic injection molds
Forming dies
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.
While 440C is a high-performance material, it is not ideal for every situation:
Corrosion resistance is limited in marine or chloride-rich environments
Lower toughness compared to austenitic grades
May become brittle at very high hardness unless carefully tempered
Machining can be difficult in hardened state
For applications requiring higher ductility or corrosion resistance, 316 or duplex stainless steels may be better alternatives.
440C stainless steel can be supplied in various surface finishes, depending on end-use requirements:
Annealed: For easy machining and forming before hardening
Ground or polished: For aesthetic or functional precision
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.
| 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.
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.