What is Martempering?

The process called martempering, which varies in many sources and is sometimes defined as quenching, can be described as a method of quenching steel. It can also be described as a material processing method for hardening steel processing. The application of the martempering process, which is sometimes called gradual quenching, is very clear. In this process, steel is heated above the upper critical point and then immersed in a lead or salt bath maintained at a temperature just above the martensitic transformation initiation temperature. The workpiece is kept in this bath-temperature until the temperature is uniform across the entire cross-section of the workpiece. Subsequently, the workpiece is cooled to room temperature in air or oil. In this way, a martensitic internal structure is obtained

What is Martensitic?

Martensite is a very hard form of steel crystal structure. Named after the German metallurgist Adolf Martens, the term by analogy can also refer to any crystal structure formed by diffusionless transformation.

What are the Martensitic Properties?

When forming martensite, carbon steels try to distribute the form to the iron carbon atoms in large enough quantities in the form of austenite by rapid cooling (between quenching). Due to its crystal structure, it contains a large amount of cementite (Fe 3 ° C) and is used to distribute it outside. Austenite is a gamma-phase iron (γ-Fe) that is a solid solution of iron and alloying elements. As a result of quenching, face-centered cubic austenite transforms into a highly stressed body-centered tetragonal form called carbon-supersaturated martensite. The resulting shear deformations cause numerous dislocations, which are the primary strengthening mechanism of steels. The highest hardness of pearlitic steel is 400 Brinell, while martensite can reach 700 Brinell. The martensite reaction begins when the austenite reaches the martensite initial temperature (M s) during cooling and the parent austenite becomes mechanically unstable. As the sample is quenched, the transformation begins when an increasingly large percentage of austenite transforms to martensite until a low transformation temperature M (s) is reached, and the process proceeds in this way.