Redtempering

Redtempering is a heat treatment process applied to steel to reduce its hardness and increase its toughness. It is typically performed after the steel has been hardened, usually through quenching. The process involves heating the hardened steel to a specific temperature, which is below its critical transformation temperature, and then holding it there for a period before cooling it. The temperature chosen for redtempering is crucial and depends on the desired properties of the final product.

The term "redtempering" refers to the color the steel often exhibits when heated to these temperatures. While the exact color can vary, it is generally within the range of pale red to dark red. The higher the tempering temperature, the softer and tougher the steel becomes, but also less hard. Conversely, lower tempering temperatures result in higher hardness with reduced toughness.

This controlled reheating process allows for the relief of internal stresses that build up during quenching, preventing brittleness. It also leads to the formation of specific microstructures that enhance the steel's ductility and resistance to fracture. Redtempering is a vital step in the manufacturing of many steel products, including tools, springs, and structural components, where a balance of hardness and toughness is required for optimal performance and durability. The specific redtempering procedure is tailored to the type of steel and its intended application.