Martensitic stainless steel is a high-strength, hardenable alloy primarily composed of chromium and carbon. It differs from other stainless steels due to its unique crystalline structure, which provides it with excellent hardness and wear resistance. Martensitic stainless steels are magnetic and can be heat-treated to enhance their mechanical properties, making them ideal for applications requiring both toughness and corrosion resistance. Common grades include 410, 420, and 440C.
High Hardness: Martensitic stainless steels can be hardened through heat treatment, achieving exceptional strength and wear resistance.
Magnetic: These steels are magnetic, which makes them suitable for applications where this property is needed.
Moderate Corrosion Resistance: While not as corrosion-resistant as austenitic or ferritic stainless steels, martensitic steels provide good resistance in less aggressive environments.
Heat Treatable: Martensitic grades can be quenched and tempered to achieve specific mechanical properties.
High Tensile Strength: These steels offer high tensile strength, making them suitable for demanding applications.
Martensitic stainless steel is produced through a series of well-controlled processes:
1. Melting: The alloy is melted in electric arc or induction furnaces, with precise control of carbon and chromium content.
2. Casting: The molten steel is cast into ingots or continuously cast into billets.
3. Hot Rolling: The billets are hot-rolled to form plates, bars, or coils, reducing the material to the desired thickness or size.
4. Heat Treatment: After forming, the steel is heat-treated by quenching and tempering to enhance hardness and mechanical properties.
5. Finishing: The final step includes surface finishing, such as grinding or polishing, depending on the desired appearance and application.
Martensitic stainless steels are chosen for applications requiring high strength, hardness, and wear resistance:
1. Knives and Cutting Tools
โข420 and 440C grades are widely used in manufacturing kitchen knives, surgical scalpels, and industrial cutting tools due to their sharpness and edge retention.
2. Automotive and Aerospace Components
โข410 is commonly used in the production of automotive parts such as bolts, valves, and shafts, where durability and moderate corrosion resistance are necessary.
3. Bearings and Gears
โข440C provides excellent hardness and is often used in high-load bearing applications, as well as gears, where wear resistance is critical.
4. Medical Instruments
โข420 grade is used in surgical instruments like scalpels, dental tools, and forceps due to its ability to be sterilized while maintaining sharpness.
5. Industrial Machinery
โขMartensitic steels are used in industrial applications such as pump shafts, hydraulic valves, and press plates where high strength and toughness are required.
Martensitic stainless steel is available in a wide range of shapes and sizes, including:
โขPlates: Thicknesses from 4 mm to 60 mm.
โขSheets: Available in thicknesses from 0.5 mm to 6 mm.
โขBars: Offered in round, square, and flat profiles, with diameters ranging from 5 mm to 200 mm.
โขCoils: Thicknesses between 1 mm and 6 mm, suitable for continuous processing.
โขPipes and Tubes: Available in both seamless and welded forms, used for precision engineering and mechanical components.
Grade |
Chromium (Cr) |
Carbon (C) |
Other Elements |
410 |
11.5-13.5% |
0.08-0.15% |
Mn, Si, S, P |
420 |
12.0-14.0% |
0.15-0.40% |
Mn, Si, S, P |
440C |
16.0-18.0% |
0.95-1.20% |
Mn, Si, Mo |
410 Stainless Steel: Offers a balance of strength, toughness, and corrosion resistance, often used in fasteners, valves, and cutlery.
420 Stainless Steel: Known for its higher carbon content, it provides superior hardness and is widely used in surgical instruments and blades.
440C Stainless Steel: The highest-carbon martensitic stainless steel, providing exceptional hardness and wear resistance, making it suitable for high-wear applications like bearings and knives.
Standard |
410 Stainless Steel |
420 Stainless Steel |
440C Stainless Steel |
China (GB) |
1Cr13 |
2Cr13 |
9Cr18Mo |
United States (ASTM) |
410 |
420 |
440C |
European Union (EN) |
1.4006 |
1.4021 |
1.4125 |
Japan (JIS) |
SUS410 |
SUS420J1 |
SUS440C |