440C stainless steel (1.4125 / SUS440C / 11Cr17) is a high-carbon, high-chromium martensitic stainless steel widely used in knife steel, bearing steel, surgical instruments, and precision components. It is known for its high hardness, excellent wear resistance, and strong corrosion resistance, making it one of the most widely used grades in high-performance applications.
With optimized carbon and chromium content, 440C provides excellent wear resistance and rust resistance, especially in humid and mildly corrosive environments. After proper heat treatment, it can achieve high hardness and stable mechanical properties, ensuring long service life and reliable performance.
Compared with other martensitic stainless steels such as 420 or 440A, 440C offers higher hardness, better edge retention, and improved wear resistance, making it ideal for high-end knives, precision bearings, and wear-resistant components.
Medical and surgical instruments
Bearings and bearing components
Valve parts and pump components
Precision wear-resistant components
| ZEICIN Grade | GB | AISI | JIS | DIN/EN |
| 1.4125 | 11Cr17 | 440C/S44004 | SUS440C | 1.4125/X105CrMo17 |
| C | Cr | Mn | Si | Mo | V |
| 0.95-1.20 | 16.00-18.00 | ≤1.00 | ≤1.00 | ≤0.75 | – |
| Co | S | P | Ni | Nb | W |
| – | ≤0.03 | ≤0.035 | ≤0.60 | – | – |
Heat to 800–920°C, followed by slow cooling to relieve stress and improve machinability.
Heat to 1010–1070°C, then oil quench to form a hardened martensitic structure.
Temper at 100–180°C to improve hardness stability, wear resistance, and overall performance.
ZEICIN Steel provides 1.4125 martensitic stainless steels in a wide range of product forms, including round bar, flat bar, square bar, and sheet. Available surface finishes include black, annealed, shot blasted, milled, peeled, centerless, and ground to meet different processing and application needs.
We offer stable quality, consistent mechanical performance, and dependable bulk supply. Customization is available for both size and chemical composition, allowing us to meet specific project and market requirements efficiently.
| Type | Specification (mm) | Surface Condition |
| Round Bar | 1-50 or Customized | Black / Centerless / Turned / Peeled |
| Flat Bar | (3-40)*(12-156)*(2000-5300) | Annerled, Shot-Blasted / Milled / Black |
| Square Bar | (6*6)-(180*180) | Annerled, Shot-Blasted / Milled / Black |
| Steel Plate | (0.6-12)*(500-1000)*(1000-3000) | Black / Sandblasted / Granding |
Different surface conditions affect appearance, dimensional accuracy, and machining allowance. The images below show common delivery options (actual products may vary by size and batch).
ZEICIN STEEL specializes in high-carbon martensitic stainless steels such as 440C. Our focus is on cleaner steel, uniform microstructure, stable heat treatment response, and improved corrosion resistance, ensuring longer service life and consistent batch performance.
Our R&D team participates in national-level research programs and key science and technology initiatives. With strong institutional support, we continuously advance the development of high-performance martensitic stainless steels, ensuring ongoing innovation and technical improvement.
We adopt an advanced melting route of EAF, LF, VD, and RS-ESR. This process improves steel cleanliness, refines carbide distribution, and enhances corrosion resistance and heat treatment stability, resulting in more reliable performance and longer service life.
We focus on the production and optimization of martensitic stainless steels such as 440C for knife blades, surgical instruments, and precision components. Our materials deliver stable hardness, excellent wear and corrosion resistance, and consistent edge performance in demanding applications.
Yes. We are a factory. ZEICIN STEEL produces high-quality, cost-effective special steels, including stainless steel, tool & die steel, and high-speed steel. We also have our own import/export license, so we can serve overseas customers directly and support stable supply with batch traceability.
Yes. For first-time cooperation, we can provide a limited quantity of samples for verification (such as grade confirmation, machining trials, or heat-treatment evaluation). Samples can be shipped by international courier, and the courier cost is paid by the buyer. We value honest cooperation and look forward to a long-term win-win partnership.
Our common international payment methods include T/T and L/C. For trade terms, we can also support options such as DDU based on the order. The final payment method and terms can be confirmed according to your country/region, order value, and delivery method.
Our products use standard industrial packaging to ensure safe transportation. If you need custom packaging, please let us know when placing your order.
If the products are in stock, delivery usually takes 5–7 days.
If the products are not in stock, delivery time is about 30–40 days, depending on the order quantity.
