440C stainless steel is a high-carbon martensitic stainless steel widely used in knife steel, surgical instruments, precision bearings, and wear-resistant components. Known as 1.4125 (DIN), SUS440C (JIS), and 9Cr18Mo (GB), this grade is one of the most popular materials for applications requiring high hardness, corrosion resistance, and long service life.
With proper heat treatment, 440C can achieve high hardness up to 55–57 HRC, while maintaining excellent wear resistance and edge retention. Its balanced performance makes it a preferred choice for high-performance knife blades, industrial cutting tools, and precision mechanical parts.
Compared with standard stainless steels, 440C offers a superior combination of hardness, durability, and corrosion resistance, especially in applications where sharpness and reliability are critical.
Kitchen and outdoor knives
Hair and pet grooming scissors
Precision bearings and mechanical components
Springs and structural parts
Medical and surgical instruments
| ZEICIN Grade | GB | ASTM | JIS | DIN |
| YTG189 | 9Cr18Mo | 440C | SUS440C | 1.4125 |
| C | Cr | Mn | Si | Mo | S | P | Ni |
| 0.95~1.20 | 16.00~18.00 | ≤1.0 | ≤1.0 | 0.40~0.65 | ≤0.03 | ≤0.04 | ≤0.75 |
Softens the steel to approximately HB 269, relieving internal stress and improving machinability.
Heat to around 1030°C, followed by rapid cooling to achieve high hardness and wear resistance.
Temper at approximately 200°C to reduce residual stress and adjust hardness. Final hardness reaches 55–57 HRC.
ZEICIN Steel supplies 440C stainless steel in various product forms, including round bar, flat bar, square bar, and sheet, with multiple surface conditions such as black, annealed, shot blasted, milled, peeled, centerless, and ground finishes.
We ensure stable quality and consistent performance. As a customizable grade, both chemical composition and dimensions can be tailored to meet specific customer requirements, with a reliable bulk supply available.
| 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.
