420 vs. 440C stainless steel: Hardness
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If you're looking for a high-hardness stainless steel for use in cutting tools, bearings, or precision components, you may have already compared 420 and 440C stainless steel. Both belong to the martensitic stainless steel family and offer high strength, high polishability, and wear resistance after heat treatment.
This article will explain the differences in hardness, composition, and mechanical properties between 420 and 440C stainless steel to help you choose the right grade for your application.
What is the equivalent material for 420 stainless steel?
Equivalent materials for 420 stainless steel include UNS S42000, European 1.4021 (X20Cr13), Japanese SUS 420J1, and Chinese 20Cr13. The specific equivalent depends on the standard you are using, such as the UNS (Unified Numbering System) or European EN standard. It can be processed into a variety of practical product forms, including plates, coils, tubes, bars, wires, etc. For detailed chemical composition and free samples, please contact our factory today.
What is 440 Stainless Steel?
440 stainless steel is a family of high-carbon, martensitic stainless steels known for their high hardness, wear resistance, and excellent edge retention after heat treatment. It is a heat-treatable alloy, and its properties vary by grade (440A, 440B, 440C, 440F), which are distinguished by their carbon content. 440C, with the highest carbon content, is the hardest and most durable, making it a popular choice for cutlery and high-strength applications like bearings.
420 vs. 440C Stainless Steel：Key differences
| Property | 420 Stainless Steel | 440C Stainless Steel |
|---|---|---|
| UNS Number | S42000 | S44004 |
| Standard | ASTM A276 / A240 | ASTM A276 / A240 |
| Carbon (C) | 0.15–0.40% | 0.95–1.20% |
| Chromium (Cr) | 12–14% | 16–18% |
| Hardness (HRC after hardening) | 48–52 HRC | 56–60 HRC |
| Tensile Strength (MPa) | 700–850 | 760–980 |
| Corrosion Resistance | Moderate | Higher (due to more Cr & C) |
| Heat Treatment | Hardenable at 980–1050°C | Hardenable at 1010–1070°C |
| Applications | Cutlery, surgical tools, shafts | Bearings, knives, molds, valve parts |
What is the difference in hardness between 440C stainless steel and 420?
440C stainless steel can be significantly harder than 420 stainless steel after heat treatment, reaching a maximum hardness of Rockwell C 60 (HRC 60), while 420 stainless steel typically reaches a maximum hardness of around HRC 55. This higher hardness makes 440C more wear-resistant and better suited for high-stress applications, but it is not as tough as 420 stainless steel. 420 stainless steel is tougher and easier to machine, making it more suitable for applications where hardness is not a primary consideration.
Which grade is better for knife blades?
440C provides better edge retention and wear resistance, making it ideal for premium knives. 420, however, is more affordable and easier to polish.
Can 420 and 440C be welded?
Both are not recommended for welding due to the risk of cracking. If welding is required, preheating and post-weld annealing are essential.
How does corrosion resistance compare?
440C performs better in mild corrosive environments, but both grades are less resistant than austenitic grades like 304 or 316.
Price
Stainless steel 440C is more expensive than stainless steel 420 due to its higher carbon content and better properties.
If you have a project need for 440C stainless steel bar, we welcome your order. GNEE has a large inventory of popular products for you to choose from. We process these products into a variety of practical product forms, including sheet, coil, tube, bar, and wire. For detailed chemical composition and free samples, please contact our factory today. We offer competitive pricing and excellent service. Email: info@gneestainless.com
