Study on hardening and deformation in laser hardening for small and thin parts: effects of dummy irradiation method.

Laser hardening process attracted attention because of its ability for a local heat treatment method without cooling solution. The local heat treatment with small power density can result in small deformation of the workpiece, which can perform without post-process for the finish. However, such superior features can be demonstrated in the case of a workpiece with large volume and heat capacity for self-cooling. Small and thin parts might not have enough volume and heat capacity for showing the features. Therefore, we proposed a novel process to complete heat treatment and deformation-less process only using a laser. The process has a laser irradiation for hardening and another laser irradiation for deformation correction. In the present paper, a fundamental study on hardening and deformation was carried out. Experimental results showed that the deformation phenomenon was complicated and quenching was difficult in laser hardening for small thin parts. Therefore, by considering factors, a method to improve was suggested. From these results, deformation and hardening phenomena occurring during laser irradiation of small thin parts were examined, and the adaptability of the proposed dummy irradiation method was shown. [ABSTRACT FROM AUTHOR]