440A stainless steel is a high-quality martensitic stainless steel widely used in knife steel, cutting tools, bearings, and precision components. Known as 1.4109 (DIN), SUS440A (JIS), and 7Cr17 / 68Cr17 (GB), this grade is valued for its excellent corrosion resistance, stable hardness, and good wear resistance.
Compared with 440B and 440C, 440A has a slightly lower carbon content, which provides better machinability and improved toughness, while still maintaining sufficient hardness for most cutting and wear-resistant applications.
With high chromium content, 440A offers strong rust resistance, especially in humid, food-contact, and outdoor environments. After proper heat treatment, it delivers stable performance, reliable hardness (~52 HRC), and long service life, making it a cost-effective choice for many industries.
Medical and surgical instruments
Medical and surgical instruments
Precision mechanical components
| ZEICIN Grade | GB | ASTM | JIS | DIN |
| YTG186 | 68Cr17（7Cr17） | 440A | SUS440A | 1.4109 |
| C | Cr | Mn | Si | Mo | V |
| 0.60~0.75 | 16.00~18.00 | ≤1.00 | ≤1.00 | ≥0.75 | – |
| Co | S | P | Ni | Nb | W |
| – | ≤0.03 | ≤0.04 | ≥0.60 | – | – |
Softens the steel to approximately HB 255, relieving internal stress and improving machinability.
Heat to around 1040°C, followed by rapid cooling to achieve increased hardness and wearresistance.
Temper at approximately 180°C to reduce residual stress and optimize hardness. Final hardnessreaches about 52 HRC.
ZEICIN Steel provides 440A 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.
