Spring steel and carbon steel are both types of steel with different properties and applications. Here are the main differences between the two:

1. Composition: Carbon steel is a broad term that encompasses a range of steels containing varying amounts of carbon. It is primarily made up of iron and carbon, with trace amounts of other elements. Spring steel, on the other hand, is a specific type of high-carbon or low-alloy steel known for its spring-like properties.
2. Carbon Content: Carbon steel typically contains carbon in the range of 0.2% to 2.1% by weight. Spring steel, specifically designed for its springiness, often has a higher carbon content, typically above 0.5% or even up to 1.5%. The higher carbon content contributes to the material's resilience and ability to return to its original shape after being deformed.
3. Mechanical Properties: Carbon steel, depending on its specific composition and heat treatment, can exhibit a wide range of mechanical properties, including strength, hardness, and toughness. Spring steel, with its higher carbon content, is specifically formulated to have excellent elasticity and resilience, making it suitable for applications that require the material to be repeatedly flexed or bent without permanently deforming.
4. Applications: Carbon steel has numerous applications across various industries, including construction, automotive, machinery, and tools, due to its strength, versatility, and relatively low cost. Spring steel, as the name suggests, is primarily used in applications that require spring-like properties, such as springs, suspension systems, clips, and other components that need to withstand repeated bending or twisting without losing their shape or functionality.
5. Heat Treatment: Both carbon steel and spring steel can undergo various heat treatment processes to modify their mechanical properties. Heat treatment techniques, such as quenching and tempering, can increase the hardness, strength, and toughness of both types of steel. However, the specific heat treatment processes may vary depending on the desired properties for the intended application.

In summary, carbon steel is a general term for steel with varying carbon content, while spring steel refers to a specific type of steel with higher carbon content designed to have excellent spring-like properties. Spring steel is tailored for applications requiring elasticity and resilience, whereas carbon steel is widely used for its strength and versatility in a wide range of industries.