Martempering is also known as ‘marquenching’, this treatment uses an elevated temperature quench.
Components are heated to the austenitizing temperature range and quenched, normally in molten salt at a temperature above the martensitic transformation start point (Ms).
Components are held in the quenching medium for sufficient time until the temperature of the component is uniform and then air cooled through the martensite formation range.
This is effectively a harden and temper operation at the same time, keeping distortion to a minimum.
Subsequent tempering is carried out to improve the materials toughness.
Since marquenching lowers the residual thermal stress, it is used for parts with complex geometries, diverse weights, and section changes.
Marquenching is used primarily to minimise distortion and eliminate cracking. Alloy steels are generally more adaptable to marquenching.
In general, any steel part or grade of steel responding to oil quenching can be marquenched to provide similar physical properties.
Benefits of Martempering
Results in properties which combine good wear resistance, high strength, ductility and toughness.
Typical materials that can be treated
This process is limited to selected carbon and low alloy of suitable section sizes.