If you’re considering using 440 stainless steel in your next project, you’ve probably wondered a little bit about its composition. Stainless steel is classified into four basic grades: 440A, 440B, 440C and 440F. In this article, we’ll discuss their characteristics, material properties, and application. Read on to learn more! You’ll be surprised how versatile and useful this material is!
Martensitic stainless steel is a type of stainless metal containing chromium that keeps Martensitic microstructure at room temperature, and whose structure can be adjusted through heat treatment (quenching and tempering). 440 Stainless Steel offers excellent abrasion resistance, as well as good corrosion resistance. It is also easy to machine, making it a popular choice for tactical blades and other similar applications. It’s also resistant to mild acids and alkalis, and is available in both hard and soft grades. Generally speaking, it is a form of hardenable stainless steel. After the quenching, tempering and annealing process, The hardness of the 440 stainless metal has been extensively increased over that of different stainless and heat-resistant steels. It is usually used in the manufacture of bearing, slicing tools, or plastic molds that require excessive masses and put on resistance underneath corrosive conditions.
440 Stainless Steel Chemical Composition
440C is identical to 440A and 440B but has a slightly higher carbon content (0.65%-0.75% and 0.75%-0.95% for the other two steel respectively). Although higher carbon content will lead to higher hardness of the blade, its corrosion resistance is slightly reduced. Although they are the same grade of standard steel, the fact is that 440C is more practical than A and B. Another alloy 440F(UNS S44020) has the same carbon content as 440C. The carbon content material of 440A, 440B and 440C extended successively. 440F (ASTM A582) is a type of free-cutting stainless steel with S content material introduced on the groundwork of 440C.
| Grades | C | Si | Mn | P | S | Cr | Mo | Cu | Ni |
| 440A | 0.6-0.75 | ≤1.00 | ≤1.00 | ≤0.04 | ≤0.03 | 16.0-18.0 | ≤0.75 | (≤0.5) | (≤0.5) |
| 440B | 0.75-0.95 | ≤1.00 | ≤1.00 | ≤0.04 | ≤0.03 | 16.0-18.0 | ≤0.75 | (≤0.5) | (≤0.5) |
| 440C | 0.95-1.2 | ≤1.00 | ≤1.00 | ≤0.04 | ≤0.03 | 16.0-18.0 | ≤0.75 | (≤0.5) | (≤0.5) |
| 440F | 0.95-1.2 | ≤1.00 | ≤1.25 | ≤0.06 | ≥0.15 | 16.0-18.0 | / | (≤0.6) | (≤0.5) |
Note: the values in brackets are allowed and not mandatory.
440 Stainless Steel Equivalent Grades
| ASTM/AISI | UNS | JIS | DIN | GB |
| 440A | S44002 | SUS 440A | 1.4109 | 7Cr17 |
| 440B | S44003 | SUS 440B | 1.4122 | 8Cr17 |
| 440C | S44004 | SUS 440C | 1.4125 | 11Cr17
9Cr18Mo |
| 440F | S44020 | SUS 440F | / | Y11Cr17 |
440 Stainless Steel Hardness
Similar to normal alloy steel, 440 series Martensite stainless metal has the traits of hardening via quenching, and can acquire a vast vary of mechanical properties via one-of-a-kind heat treatments. In general, 440A has amazing hardening overall property and excessive hardness, and its sturdiness is greater than that of 440B and 440C. 440B has a higher hardness and longevity than 440A and 440C for cutting tools, measuring tools, bearings and valves. The 440C has the very best hardness of all stainless metal and heat-resistant metal for tremendous reducing tools, nozzles and bearings. 440F is free-cutting metal and normally used in automated lathes.
| Grades | Hardness, Annealing（HB） | Heat treatment（HRC） |
| 440A | ≤255 | ≥54 |
| 440B | ≤255 | ≥56 |
| 440C | ≤269 | ≥58 |
| 440F | ≤269 | ≥58 |
440 Stainless Steel Applications
440 stainless steel is an excellent choice for blades and has been widely used in the manufacture of knives, forks, and more. Because it’s harder than most steels, however, 440’s sharpness and machinability make it ideal for a variety of applications. 440A stainless steel has excellent quenching and hardening performance, high hardness, and high toughness than 440B and 440C, used to manufacture tools, measuring tools, and bearings. 440B stainless steel has higher hardness and toughness than 440A steel and is used for cutting tools, measuring tools and bearings, valves or as bayonet blade material.
The most popular stainless steel for knives is 440C, which is particularly useful for blades, valves, and other applications that require hardness above 60 and other products that don’t require high tensile strength. It is a popular choice for high-quality knife making on a budget. This material’s hardness is 60 HRC, which makes it an excellent choice for high-quality blades at a fraction of the price of other stainless steel. You can even purchase 440C stainless steel with a hefty discount and save a significant amount of money in the process. Because it has a high amount of chromium, it won’t rust in the air. However, the downside of 440 is that its razor edge won’t hold for very long. Harder alloys like 440B and 440F are available.
If you have questions about 440 steel or get a 440F stainless steel price, contact us! We’re always happy to answer your questions.
