Case-hardening steel, also known as surface-hardenable steel, contains a maximum of 0.3% carbon. In addition to carbon, these steels include other elements such as manganese, molybdenum, nickel, and chromium. This combination of elements gives case-hardening steels special properties, such as high resistance to wear and impact. For this reason, these steels are highly valued in industries that require durability and long service life.

Some common applications of case-hardening steel include the design and manufacture of gears, steering system components, as well as in the plastics and melamine industries. Due to their ability to be surface hardened, these steels are used in components that require high surface resistance.

The term case-hardening refers to the process of surface hardening. One well-known type of this steel is 1.7131 steel, also known commercially as Ec80. It is widely used in the production of components such as gears. Another example is 1.6587 steel, which has similar properties.

Other applications of case-hardening steel include the production of shafts, pins, bushings, and industrial machinery components. Due to their ability to withstand heavy loads and harsh working conditions, these steels are also very useful in the manufacturing of heavy machinery and equipment. Additionally, because of their superior mechanical properties, case-hardening steels are used in the automotive and aerospace industries, where the safety and performance of parts are critical.