What is High Carbon Stainless Steel?

In stainless steel materials, High Carbon Stainless Steel plays a dual role. On one hand, it serves as an austenite-stabilizing element, exerting an influence that is roughly 30 times greater than that of nickel. High carbon martensitic stainless steels can be fully hardened by quenching, which greatly improves their mechanical properties. However, carbon has a strong affinity with chromium (Cr), leading to the formation of chromium carbides, which reduces the steel’s corrosion resistance. As the carbon content increases, this carbide formation accelerates, further diminishing corrosion resistance. This creates a paradox where carbon increases the material’s strength but compromises its corrosion resistance.

Carbon Content and Corrosion Resistance

In practice, to ensure corrosion resistance, the carbon content in stainless steel is usually kept low, often around 0.1%. In applications where enhanced corrosion resistance is required, especially to prevent intergranular corrosion, ultra-low carbon stainless steels with a carbon content of 0.03% or lower are used. However, in products that require hardness and wear resistance, such as bearings, springs, and tools, the carbon content is elevated, often between 0.85% and 1.00%, characterizing high carbon stainless steel.

Comparison of Tensile Strength of Stainless Steel

Stainless steel comes in various types, each with unique mechanical properties. One of the key factors to consider when selecting stainless steel for specific applications is its tensile strength, which indicates how much stress the material can withstand before breaking. Below is a comparison of the tensile strength of the three most common types of stainless steel.

Austenitic Stainless Steel

Tensile strength ranges from 72,000 to 115,000 pounds per square inch (psi).

Martensitic Stainless Steel

Tensile strength ranges from 72,000 to 160,000 psi.

Ferritic Stainless Steel

Tensile strength ranges from 65,000 to 87,000 psi.

Uses of High Carbon Stainless Steel

High carbon steel has been historically significant as the earliest known form of steel. It is classified based on carbon content, which defines its hardness and wear resistance.

Advantages and Disadvantages

High Carbon Stainless Steel is highly valued for its hardness, good wear resistance, and long-lasting sharpness, making it popular among professional chefs and knife enthusiasts.

Disadvantages

However, it is more susceptible to corrosion, requiring careful maintenance such as drying and oiling after use.

Common Applications of High Carbon Stainless Steel

Adding carbon to martensitic stainless steel increases its strength and hardness but reduces weldability, toughness, and corrosion resistance. More carbides are formed, requiring higher austenitizing temperatures to dissolve, which can negatively affect impact performance.

Knives

High carbon stainless steel is widely used in kitchen knives (e.g., 5CR15MOV, 9CR18MOV, 10CR18MOV, German 1.4116), offering good hardness and edge retention.

Gears, Bearings, and Valves

Used in high-temperature applications.

Razor Blades and Surgical Instruments

Known for their durability and sharpness.

Aerospace and Defense Tools

Due to their durability, strength, and corrosion resistance, these materials are used in demanding applications, including ball bearings and coal hammers.