PROCESS FOR HARDENING GROOVE FLANKS OF THE ANNULAR GROOVE OF A STEEL PISTON BY MEANS OF A LASER BEAM

摘要

The invention proposes a process for hardening groove flanks of the annular groove (11) of a steel piston (5) by means of a laser beam (3), wherein oxygen-containing process gas is initially directed at a groove flank (10) of the steel piston (5) and the steel piston (5) is set in rotation. In the process, the groove flank (10) is irradiated with the laser beam (3) until an oxide layer has formed on the groove flank. The supply of process gas is then disconnected and the groove flank (10) is heated and hardened in tracks. Firstly, the oxide layer on the groove flank improves the degree of heat input into the groove flank, and this results in quicker heating and hardening of the groove flank. Secondly, this reduces the reflectivity of the groove flank, and only a small amount of light is therefore reflected from the groove flank onto other areas of the groove, with the result that these areas are not undesirably heated and hardened.