Description
CPM S35-VN - Stainless Blade Steel Flat Bars
This steel is manufactured in the USA by Crucible Industries and is supplied hot rolled and annealed. It has a textured surface from the hot rolling process and is soft, making it easy to cut, grind, drill, and file in its annealed state. Exact thickness may vary from batch to batch.
CPM S35VN stainless steel was introduced in 2009 as an evolution of CPM S30V. Designed specifically for knives, it was developed with input from knife makers and professionals. The alloy includes niobium, which contributes to its toughness and wear resistance, offering improved overall performance compared to its predecessor. The particle metallurgy process used to make CPM S35VN ensures a uniform distribution of alloying elements, fine grain structure, and small carbide size, enhancing its wear resistance and toughness.
One of the key innovations in CPM S35VN is the addition of 0.5% niobium, which enhances toughness and makes the steel easier to machine compared to CPM S30V, without sacrificing edge retention or corrosion resistance.
Composition
- Carbon – 1.40%
- Molybdenum – 2.00%
- Manganese – 0.50%
- Silicon – 0.50%
- Chromium – 14.00%
- Vanadium – 3.00%
- Niobium – 0.50%
- Iron – Balance
Performance Characteristics
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Toughness 6/10 – Good toughness, better than CPM S30V and many other stainless steels, making it suitable for medium to large blades, from everyday carry (EDC) knives to tactical and outdoor use. It is tough enough for most knife applications and strikes a good balance between toughness and edge retention.
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Edge retention 6.5/10 – CPM S35VN offers superior edge retention compared to most stainless steels, largely due to the vanadium carbides and niobium in its composition. It holds an edge well, and while not as hard as premium steels like M390, it maintains a balance between edge holding and ease of sharpening.
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Corrosion resistance 8/10 – Excellent corrosion resistance, comparable to other high-end stainless steels like CPM 154 and NitroV. CPM S35VN's chromium content provides a strong resistance to rust, making it ideal for knives used in humid, outdoor, or corrosive environments.
Recommended Heat Treatment
- Coat blade in an anti-scale compound or seal in double crimped 321 or 309-grade stainless steel tool wrap
- Austenitise – Heat to 1065-1080°C and hold for 30 minutes
- Quench between aluminum plates or oil quench
- Cryogenic Treatment – Immerse in liquid nitrogen or dry ice slurry for 1 hour or more to convert retained austenite to martensite and increase hardness
- Temper at 150-230°C for 2 hours, twice, depending on the desired hardness
Note: For best results, use liquid nitrogen or dry ice after quenching to achieve maximum hardness. Without cryogenic treatment, austenitising at 1050-1065°C can still yield good results, with a slight reduction in hardness.
Approximate As-Quenched Hardness Before Tempering:
- 1080°C followed by liquid nitrogen – 61-62HRC
- 1080°C followed by dry ice – 60-61HRC
- 1050°C followed by freezer – 59HRC
Recommended Working Hardness
58-62HRC
