In-Process Hardening in Laser Supported Incremental Sheet Metal Forming

The effect of localized laser hardening on the dimensional accuracy of incrementally formed steel sheets has been studied. By dynamically heating by means of laser beam scanning (500W Nd:YAG) the temperature of the sheet reaches the austenization temperature and by subsequent self-quenching a hard martensitic structure will form. Using FE modeling, a laser power setting of 202 W, scanning velocity of 600 mm/min and beam diameter of 6 mm were selected as optimum processing parameters for transformation hardening. Hardness tests were performed in order to investigate the hardness profile along the depth and width of the laser hardened zone. Experimental results reveal that generation of a selectively hardened martensitic band, formed by transformation hardening, can increase the accuracy of the incrementally formed part.