Medium carbon steel provides a balance between low and high carbon steel, offering greater strength and hardness than low carbon steel while still remaining more ductile than high carbon steel. Medium carbon steel also typically contains other alloys, such as manganese, that also contribute to its properties.

  In applications where greater toughness and hardness are required, medium carbon steel plate can receive heat treatments – such as quenching and tempering – that enhance these properties without compromising its machinability.

  Quenching and tempering is a two-step heat treatment process. In the quenching step of this process, steel is heated to a temperature between 1,500-and 1,650-degrees Fahrenheit, then rapidly cooled with water. In the tempering step, the steel is then re-heated to a below-critical temperature – between 300 and 700 degrees – and air-cooled. This process alters the crystal grain structure of steel to enhance hardness and other mechanical properties.

  Two common medium carbon steel plate grades that Leeco stocks are ASTM A516 Grade 70 and A830-1045. The moderate carbon composition and additional alloys give these grades – and other medium carbon grades – a balance of strength, hardness, ductility and wear resistance. These properties make medium carbon steel ideal for use in applications where materials must withstand strong forces without breaking or wearing out, such as machine parts – including gears, axles and bolts – pressure vessel tanks and automotive parts and components.

Chemical Composition of Common Medium Carbon Plate Grades