CPM S35VN Steel: Properties, Process, Applications

CPM S35VN steel is a high-performance steel. Its unique mix of vanadium, niobium, and chromium carbides ensures excellent edge retention and machinability. In this article, we will explore its performance, heat treatment, uses, and comparison with other steels 

What Is CPM S35VN Steel?

CPM S35VN steel is a high-performance martensitic stainless steel developed for knife-making. Part of the CPM series, it offers outstanding durability, abrasion resistance, and long-lasting sharpness. Its composition, with vanadium, niobium, and chromium carbides, enhances both hardness and toughness. S35VN excels in kitchen knives, outdoor blades, and rescue tools. 

Compared to traditional high-carbon steels like 440C and D2, it provides better edge retention and corrosion resistance. Its finer grain structure makes it easier to machine, grind, and polish than S30V, making it ideal for durable knives with long-lasting sharpness in harsh environments.

Is S35VN Stainless Steel?

Yes, S35VN is a high-performance martensitic stainless steel. It offers It provides outstanding corrosion resistance, making it perfect for applications like kitchens and outdoor activities, while maintaining exceptional toughness and wear resistance.

Is S35VN A Super Steel?

Yes, S35VN is often considered a “super steel” due to its advanced composition and superior properties. With the addition of vanadium and niobium carbides, it combines exceptional toughness with great wear resistance.

What Is CPM S35VN Steel Equivalent To?

CPM S35VN is often compared to steels like S30V, 440C, and D2. While S35VN offers improved toughness and machinability over S30V, it maintains similar wear resistance and edge retention. Compared to 440C and D2, S35VN stands out for its rust resistance, making it a superior choice for blades used in damp or corrosive conditions.

CPM S35VN Steel Chemical Composition

CPM S35VN tool steel offers a balanced alloy composition, providing excellent hardness, wear resistance, and toughness. The presence of vanadium (V) and niobium (Nb) carbides enhances toughness by reducing the amount of chromium carbide, improving edge fracture resistance without sacrificing wear resistance.  

The table below details the exact chemical makeup of CPM S35VN.

CPM S35VN Steel Physical Properties

CPM S35VN steel offers high density, excellent thermal conductivity, and low thermal expansion. The table below summarizes the key physical properties of CPM S35VN steel.

CPM S35VN Steel Mechanical Properties

CPM S35VN steel exhibits high hardness, exceptional tensile and yield strength, and good elongation, making it suitable for applications requiring both strength and durability. Its modulus of elasticity and Poisson’s ratio reflect its stability under stress. 

The table below summarizes the key mechanical properties of CPM S35VN steel.

Characteristic of CPM S35VN steel

Superior Edge Retention

With a hardness of 58–60 HRC, CPM S35VN outperforms S30V by 15-20% in edge retention. The carbides from vanadium and niobium contribute to its exceptional resistance to wear and abrasion, maintaining sharpness longer and reducing the need for frequent sharpening.

High Toughness

CPM S35VN boasts a fracture toughness of 30-35 MPa·m^1/2, thanks to niobium. This makes it more resistant to chipping and cracking under stress, striking a balance between hardness and durability.

Excellent Corrosion Resistance

With 14% chromium, S35VN excels in corrosion resistance, performing well in salt spray tests with minimal rust formation. Its ability to resist moisture and acids ensures long-lasting performance in harsh environments.

Good Machinability

S35VN offers good machinability, easier than S30V, due to its fine grain structure and niobium. It allows for precise machining without excessive tool wear, maintaining high performance throughout the process.

Efficient Grindability

S35VN is easy to grind, even at hardness levels up to 60 HRC. Its fine-grain structure allows for quick sharpening and fine edge formation, improving efficiency during manufacturing.

How Good Is S35VN Steel?

S35VN steel performs exceptionally well in applications like kitchen knives, outdoor tools, and rescue blades, offering a balance of sharpness, durability, and ease of maintenance. It is a top choice for anyone needing a reliable, long-lasting cutting edge.

Forging Guidelines For CPM S35VN Steel

We recommend forging CPM S35VN at 2100°F (1150°C) and avoiding temperatures below 1750°F (950°C) to preserve its optimal properties. Proper temperature control ensures the steel maintains its fine grain structure and toughness throughout the process.

CPM S35VN Steel Heat Treatment

At SteelPro Group, we know that CPM S35VN steel is like a fine wine – it needs the right heat treatment to truly shine. That is why we follow precise, expert processes to ensure every piece of CPM S35VN is properly treated, maximizing its performance for top-notch results.

Annealing

To anneal CPM S35VN, heat it to 1650°F (900°C), hold it for 2 hours, then cool it slowly at no more than 25°F (15°C) per hour to 1100°F (595°C). Afterward, let it cool in still air or a furnace to room temperature. This process results in an annealed hardness of approximately BHN 255, providing an excellent starting point for machining.

Stress Relieving

For annealed parts, we recommend heating to 1100-1300°F (595-705°C), holding for 2 hours, then cooling in still air or a furnace. For hardened components, raise to 25-50°F (15-30°C) lower than the initial tempering temperature, maintain for 2 hours, and then allow to cool. This relieves internal stresses while maintaining the steel’s stability.

Hardening

The hardening process begins with preheating at 1550-1600°F (845-870°C) to equalize the steel. Austenitize at 1900-2000°F (1035-1095°C) for 15-30 minutes, followed by quenching. 

Cool the material to below 125°F (50°C) by air or positive pressure quenching with a minimum pressure of 2 bar. Alternatively, employ salt or interrupted oil quenching to approximately 1000°F (540°C), followed by air cooling to bring the temperature down.

Tempering

Double temper CPM S35VN at temperatures ranging from 400-750°F (200-400°C), maintaining each cycle for a minimum of 2 hours. For enhanced hardenability, we suggest adding a freezing treatment between tempers, such as liquid nitrogen for at least 30 minutes. For optimum stress relief, tempering at 1000-1025°F (540-550°C) is effective, though it may slightly reduce corrosion resistance.

Recommended Heat Treatment

For the best balance of hardness, toughness, and corrosion resistance, we recommend austenitizing at 2025°F for 15 minutes, plate quenching, a liquid nitrogen treatment for 30 minutes, and double tempering between 300-400°F for 2 hours each. Adjust the tempering temperature based on your desired hardness, which typically ranges from 58-61 Rc.

CPM S35VN Steel Product Forms

At SteelPro Group, we offer CPM S35VN steel in common forms and custom-size options to meet specific requirements. We focus on the most widely used dimensions that guarantee optimal performance for various applications, with flexibility for unique needs.

Plates and Sheets

• Thickness: 12.7mm (0.5″) to 50.8mm (2″)
• Width: 152mm (6″) to 305mm (12″)

Round Bars

• Diameter: 12.7mm (0.5″) to 101.6mm (4″)
• Length: 305mm (12″) to 610mm (24″)

Blade Material

• Thickness: 2.5mm (0.1″) to 6.4mm (0.25″)
• Width: 25.4mm (1″) to 101.6mm (4″)

Bars

• Diameter: 6.35mm (0.25″) to 50.8mm (2″)
• Length: 305mm (12″) to 914mm (36″)

CPM S35VN Steel Applications

CPM S35VN steel is commonly used for high-performance tools, including:

• Cutting Tools – High-end kitchen knives and precision cutting instruments.
• Knives – Premium fixed and folding knives for outdoor and tactical use.
• Outdoor Gear – Survival knives and multi-tools.
• Industrial Tools – Blades, dies, and cutters for manufacturing and machining.
• Tooling – High-performance tooling for fabrication and metalworking.

Nitro V Steel VS S35VN Steel

Nitro V and S35VN are both premium steels used in knives, but Nitro V has a higher chromium content, giving it better corrosion resistance, while S35VN excels in toughness due to the addition of niobium. S35VN tends to have slightly better edge retention, while Nitro V is easier to sharpen.

S35VN VS D2 Steel

S35VN offers superior toughness and corrosion resistance compared to D2, which is more prone to rusting. D2 has excellent wear resistance but is more difficult to machine. S35VN, with its niobium and vanadium carbides, offers a better balance of edge retention and ease of sharpening.

At SteelPro Group, we also offer a wide range of D2 tool steel products, including plates, bars, and custom sizes, for those looking for excellent wear resistance in their applications.

420HC VS S35VN Steel

420HC is a budget-friendly stainless steel with decent corrosion resistance, commonly used in affordable knives. S35VN, however, delivers much better edge retention, toughness, and wear resistance, making it ideal for higher-end knives used in demanding environments. S35VN is also easier to machine and sharpen than 420HC.

SteelPro Group: Your CPM S35VN Steel Solution

At SteelPro Group, we don’t just provide CPM S35VN steel—we deliver precision. We offer common sizes and custom dimensions tailored to your needs. Our services include cutting, grinding, machining, and heat treatments like hardening and tempering to optimize performance.

With our expertise, you get more than just steel. We ensure it’s ready to perform in your toughest applications. Let us handle the details, so you can focus on what matters.