440C Stainless Steel Plate for Knife Making: Hardness & Price
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If you are sourcing 440C stainless steel plate for knife making, achieving the required hardness is only part of the purchasing decision. The plate must also maintain acceptable flatness after heat treatment and provide a consistent surface finish for precision grinding and final polishing.
What is AISI 440C material plate?
440C stainless steel plate is widely used for knife making due to its high carbon content of 0.95–1.20% and chromium content of 16–18%, offering excellent hardness, wear resistance, and edge retention. After appropriate heat treatment, 440C can achieve approximately 58–60 HRC, making it suitable for high-performance knife blades and cutting tools. Its corrosion resistance is good in many everyday environments, although proper heat treatment and surface finishing are essential. Buyers should confirm plate thickness, dimensional tolerances, annealed condition, and material certification before ordering.
440C Stainless Steel Chemical Composition (wt. %)
| Element | C | Cr | Mo | Mn | Si | P | S | Ni | Fe |
| Range / Max | 0.95 – 1.20 | 16.0 – 18.0 | 0.75 – 1.00 | ≤ 1.00 | ≤ 1.00 | ≤ 0.040 | ≤ 0.030 | ≤ 0.75 | Bal. |
Key Designation Logic: "440" = 400 series (martensitic stainless); "C" = highest carbon variant (A: 0.60–0.75%, B: 0.75–0.95%, C: 0.95–1.20%)
What Is the Best HRC for 440C Knife Blades?
For most 440C stainless steel knife blades, 58–60 HRC is a practical target hardness, balancing edge retention, wear resistance, and usable toughness. With proper heat treatment, 440C can reach approximately 60–62 HRC under certain conditions, but higher hardness may increase the risk of edge chipping in impact-heavy applications. Buyers should specify the required HRC range and verify the final hardness after heat treatment.
440C Stainless Steel Plate :Hardness Before & After Heat Treatment
Hardness by Condition
| Condition | Process | Hardness | Notes |
| As supplied (annealed) | Furnace anneal 843 – 871 °C (1,550 – 1,600 °F), slow cool | 223 HBW / ~23 HRC (max 269 HBW / 28 HRC) | Machinable state |
| Process annealed | 732 – 760 °C (1,350 – 1,400 °F), air cool | ~255 HBW / ~25 HRC | Intermediate softness |
| As quenched (untempered) | Austenitize 1,010 – 1,065 °C (1,850 – 1,950 °F) → oil quench | 60 – 62 HRC | Brittle; must temper immediately |
Why Does 440C Warp After Heat Treatment?
During the heat treatment of 440C stainless steel, warping or deformation can occur due to uneven heating or cooling, residual stresses, and volume changes associated with the martensitic transformation. Thin sheets and long, strip-like blade blanks are particularly susceptible to such dimensional distortion. For thin blade blanks (2–4 mm), bending, twisting, and warping following heat treatment are the primary reasons for product rejection in knife-making workshops-far more so than insufficient hardness.
How to Prevent Heat Treatment Distortion in 440C Stainless Steel?
GNEE Stainless helps minimize deformation through controlled preheating, uniform temperature distribution, proper quenching techniques, and appropriate fixtures. For precision knife-making plates, machining allowances should be retained, followed by post-heat-treatment leveling or precision grinding, with subsequent inspection for flatness and thickness.
Standard workflow to control flatness:
Pre-stress relief → Controlled vacuum hardening → Oil quench → Cryogenic treatment (optional) → Low temp double temper → **Flattening / stress straightening under fixture** → Fine grinding → Double-side polishing.
Verifying flatness on a granite surface plate using a straightedge and feeler gauges
440C Stainless Steel Plate Suppliers and Manufacturers
Our 440C stainless steel plate for knife making is supplied in stress-relieved annealed condition to mitigate the common challenge of heat treatment distortion. After vacuum hardening and tempering to the target 58–60 HRC, we carry out precision fixture flattening to control flatness within 0.03 mm per 100 mm length. The blanks then go through sequential abrasive grinding and double-side polishing, available in satin or mirror finish, eliminating waviness and grinding lines. We provide full MTC, PMI and hardness test certificates with each batch.
Below is a video of the 440C stainless steel plates we just delivered to a client.
What is 440C stainless steel plate price per kg ?
The price of 440C stainless steel plate typically ranges from $3.50 to $8.80 per kilogram, depending on factors such as plate thickness, dimensions, material condition, order quantity, and processing requirements. Prices can vary significantly between annealed plates and products that require further processing-such as heat treatment, precision grinding, leveling, or double-sided polishing.
To obtain an accurate quote from GNEE, please specify the required thickness, width, length, quantity, target hardness (HRC), and surface finish requirements.
What is the difference between 440A, 440B and 440C for knives?
440A, 440B and 440C are martensitic stainless steels distinguished mainly by carbon content. 440A (~0.65–0.75% C) maxes out at 57–58 HRC with good stain resistance. 440B (~0.75–0.95% C) reaches 58–59 HRC for balanced performance. 440C (~0.95–1.20% C) achieves 58–62 HRC after proper heat treatment, delivering superior edge retention yet higher distortion risk and slightly lower corrosion resistance, making it the preferred grade for premium knife blades.
440C vs Common Knife Steels
| Property | 440C | 1084 (Carbon) | D2 (Tool) | 154-CM | S30V (PM) | 26C |
| C (%) | 0.95 – 1.20 | 0.80 – 0.95 | 0.90 – 1.00 | 1.05 – 1.25 | 1.05 – 1.45 | 0.70 – 0.85 |
| Cr (%) | 16 – 18 | 0.2 – 0.5 | 11 – 12 | 13.5 – 14.5 | 14 – 14.5 | 14 – 14.5 |
| Max Hardness (HRC) | 60 | 64 | 60 – 62 | 60 – 62 | 60 – 62 | 60 – 62 |
| Edge Retention | 8.5 | 7.0 | 8.0 | 8.5 | 9.0 | 8.5 |
| Corrosion Resistance | 6.0 | 2.0 | 5.0 | 7.0 | 8.0 | 7.5 |
| Toughness | 5.5 | 8.0 | 5.5 | 6.0 | 6.5 | 7.0 |
| Ease of Sharpening | 6.0 | 8.0 | 5.5 | 6.0 | 5.0 | 6.5 |
| Cost (relative) | 1.0× | 0.7× | 1.5× | 2.5× | 4.0× | 2.0× |
If you would like to narrow down your options further, please let me know:
• What type of knife steel are you looking for?
• What is your budget, or do you have a preference for specific sharpening tools?
I can help you select the most suitable steel based on your individual needs.
FAQ
1. Can 440C steel improve its toughness through tempering?
Yes. After quenching, 440C stainless steel typically reaches a hardness of approximately 58–60 HRC. Proper tempering can reduce internal stresses and improve toughness, although hardness varies with tempering temperature and time. For 440C knife steel, the heat treatment process should be designed according to the target hardness, wear resistance, and resistance to edge chipping, with the final properties verified through hardness testing.
2. Can 440C steel be flattened after quenching?
Yes, but quenched 440C steel has high hardness and increased brittleness, so direct mechanical flattening may cause cracking or edge chipping. For knife steel plates with thicknesses of approximately 2–10 mm, it is advisable to allow sufficient stock for flattening and finish machining before heat treatment. If distortion remains after quenching, qualified heat treatment specialists should assess controlled straightening or grinding correction and inspect dimensional tolerances and surface cracks.
3. Does 440C steel require cryogenic treatment?
Not necessarily. Cryogenic treatment of 440C steel is generally performed after quenching and before tempering, at temperatures ranging from approximately −70°C to −196°C, to promote the transformation of retained austenite into martensite, improve dimensional stability, and help achieve the target hardness. Cryogenic treatment may benefit high-wear-resistance knives and precision components, but the decision should depend on the steel composition, quenching process, and final hardness requirements. It is not mandatory for every 440C product.
4. Do 440C steel knives require double-sided polishing?
Not necessarily. The requirement mainly depends on the knife's application and surface finish specifications. Precision knives, collectible knives, and blades with high aesthetic requirements may benefit from double-sided polishing to improve surface finish and facilitate cleaning. Industrial knives may use single-sided polishing, double-sided grinding, or other surface treatments according to machining requirements. When purchasing, specify the required surface roughness, such as Ra ≤ 0.8 μm, and confirm flatness on both sides, thickness tolerances, and whether a mirror finish is required.
5. What certification documents should buyers request when purchasing 440C knife steel?
When purchasing 440C knife steel plates, buyers should request a Material Test Certificate (MTC) listing the chemical composition, heat number, and material grade, and verify compliance with the agreed standard or grade designation, such as UNS S44004. For heat-treated products, a hardness test report, for example, confirming a target hardness of 58–60 HRC, and relevant heat treatment records should also be requested.
6. What are the standard minimum order quantity (MOQ) and lead time for 440C knife steel plates?
The MOQ for 440C knife steel plates depends on thickness, width, surface condition, and stock availability. As a purchasing reference, stock orders may start at approximately 100–500 kg, with a typical lead time of 7–15 days. Non-standard thicknesses, special tolerances, or customized heat treatment may require 30–45 days. These figures are estimates rather than universal industry standards. When requesting a quotation, buyers should specify thickness, width, length, target hardness, surface finish, and order quantity so the supplier can confirm stock availability, MOQ, and actual lead time.
