Optimised press-hardening process using spray cooling: process integrated heat treatment of 22MnB5 sheet metal

Press-hardening is a comparatively time consuming forming process since both forming as well as quenching is performed in the die tool. In order to accelerate this process, an alternative cooling strategy is considered which is based on spray cooling outside the die tool. The object of our investigation is 22MnB5 material. Quenching tests show that sufficient cooling rates greater than 50 K/s can be obtained by means of water-air spray cooling using two-component nozzles. The strength values and fracture strains realised here correspond to the mechanical properties attainable during press-hardening. Furthermore, a plant design is presented which is suitable for cooling vehicle body parts such as tunnels in order to reduce the turnaround time by means of prematurely removing the components from the die-forming tool and subsequently cooling in a spray field.