5160

5160 is a high-carbon alloy steel in the SAE/SAE-JIS family commonly marketed as a spring steel. It is widely used for automotive leaf springs due to its toughness and fatigue resistance, and it is also popular in the knife and blade-making community for its combination of strength and shock resistance. The grade is sometimes referred to simply as AISI 5160 or SAE 5160.

Composition and properties: 5160 is a chromium-containing, manganese-bearing steel with a relatively high carbon content. Typical ranges describe carbon around 0.56–0.64%, chromium roughly 0.75–1.25%, and manganese about 0.60–0.90%, with silicon in the low-to-mid fractions. This composition gives high toughness and good elastic recovery, making it suitable for parts that must absorb impact without brittle failure. It is not a stainless or highly corrosion-resistant alloy, so surface protection is commonly required in environments where rust is a concern.

Heat treatment: The steel is usually heat treated to maximize toughness. Common practice involves austenitizing and oil quenching followed by tempering. Hardened hardness often falls in the range of about 56–60 HRC, with tempering temperatures typically in the mid-range that prioritize toughness over maximum hardness. Stock forms used include bars and sheet for springs, and blades or sword fittings in the blacksmithing and knifemaking communities.

Applications: Beyond automotive springs, 5160 is widely used for robust blades requiring resilience and impact resistance, including large outdoor knives, bushcraft blades, and swords. It is also found in other spring components and heavy-duty structural parts where toughness is prioritized over corrosion resistance. Availability is broad through steel distributors and knife-makers, with varying heat-treatment guidance depending on the intended use.