Experimental fatigue performance of laser-formed components

Much knowledge has been gained with respect to the forming of sheet material by laser technology since its inception during the mid-1980s. However, many press-formed sheet metal components are subjected to cyclic loading conditions during their service life. It is from this standpoint that the work reported in this paper originates. This work deals with some aspects of the structural integrity of laser-formed plate samples that were formed to a radius of curvature of approximately 125 mm. Furthermore, a comparison is drawn between laser-formed and stock plate samples fatigue tested under reverse-bending cyclic conditions. The results indicate that the fatigue life of the laser-formed samples was substantially enhanced when compared to that of the stock plate samples. This observed improvement in fatigue life is attributed to the laser-hardening mechanism, i.e., the phase transformation and rate of cooling of the material from above the A3 temperature, i.e. approximately 1200 °C. This aspect of improved fatigue life is considered to be beneficial to the motor manufacturing industry that could result in the possible use of thinner gauge material.