Single-row laser beam with energy strengthened ends for continuous scanning laser surface hardening of large metal components

For laser surface hardening of metal components with large superficies, a binary grating is proposed to generate single-row laser beam with proportional-intensity diffractive orders. To obtain a uniform hardened band distribution and improve the wear resistance of the sample surface, the binary grating is designed to produce single-row laser beam with energy strengthened at the two ends. The profile of the laser beam spot was designed to be strip with high length-width ratio to improve the machining efficiency of the hardening of large surfaces. A new advantage is suggested to obtain proportional intensity spots with evenness. The design results show that the diffractive efficiency of the binary grating is more than 70%, and the uniformity is less than 3%. The surface profile of the grating fabricated was measured, which shows that the fabrication error is less than 2%. The application of the binary grating in the laser surface hardening of metal components with large superficies is experimentally investigated, and the results show that the hardness distribution of the modified layer is more uniform than that hardened by Gaussian laser beam or array spots with equal intensity distribution.