What is "spring steel"

Spring steel \Spring steel\ A variety of steel, elastic, strong, and tough, rolled for springs, etc.

Spring steel is a name given to a wide range of steels used widely in the manufacture of springs, prominently in automotive and industrial suspension applications. These steels are generally low-alloy, medium-carbon steel or high-carbon steel with a very high yield strength. This allows objects made of spring steel to return to their original shape despite significant deflection or twisting.