Spring steel is typically made from various types of high-carbon or low-alloy steels. The specific composition of spring steel can vary depending on the desired properties and application requirements. Some commonly used materials for spring steel include:

1. High-carbon steel: High-carbon steel contains a higher percentage of carbon, typically ranging from 0.50% to 1.25%. This increased carbon content contributes to the hardness, strength, and resilience of the spring steel. Grades such as AISI 1070, 1095, or 5160 are examples of high-carbon steels used for spring applications.
2. Low-alloy steel: Low-alloy steels contain small amounts of alloying elements in addition to carbon. These elements can include chromium, manganese, silicon, or vanadium. The addition of alloying elements helps enhance specific properties such as strength, toughness, or corrosion resistance. Grades like AISI 9260 or 6150 are examples of low-alloy steels used in spring applications.

It's important to note that spring steel can also refer to other materials besides steel. Some non-ferrous metals, such as beryllium copper or phosphor bronze, are also used in certain spring applications due to their specific properties like conductivity or resistance to corrosion.

In general, spring steel is chosen for its combination of strength, toughness, elasticity, and durability. The specific material selection depends on factors such as the required load-bearing capacity, environmental conditions, and the desired performance characteristics for the particular spring application.