Known for its good balance of durability, sharpness, and corrosion resistance, 440 stainless steel has become a favorite among knife enthusiasts and manufacturers. 440 stainless steel is a family of alloy steels containing varying amounts of carbon, chromium, and other elements. The 440 series is typically composed of three main variants: 440A, 440B, and 440C. Each variant has slightly different compositions, resulting in varying hardness levels, corrosion resistance, and edge retention.

440A takes a different approach with a lower carbon content, usually falling between 0.60% and 0.75%. This lower carbon amount makes 440A a bit softer than its counterparts, but it's a trade-off for being less susceptible to corrosion. With a chromium content of 16% to 17%, 440A boasts the best corrosion resistance among the 440 steels. While this is beneficial for longevity, it comes at the expense of some hardness, making it easier to sharpen but also more prone to wear over time.

Stepping up, 440B presents a higher carbon content ranging from 0.75% to 0.95%, striking a balance between 440A and 440C. This moderate carbon increase results in improved hardness compared to 440A, offering better edge retention at the cost of some toughness. This composition positions 440B as a versatile choice, balancing corrosion resistance and durability.

On the higher end of the 440 stainless steel family, 440C boasts the highest carbon content ranging from 0.95% to 1.20%, earning it the reputation of being the hardest in the series. This hardness translates to excellent edge retention, but it comes with challenges. 440C is harder to sharpen due to its high carbon content and offers comparatively less corrosion resistance within the 440 stainless steel family.