Study on the influence of preheating conditions on the fiber laser direct writing coloring of stainless-steel surface

Laser coloring of metal surfaces is widely studied for its diverse applications and significant advantages. This study examines the impact of preheating temperature on fiber laser coloring of 304 stainless-steel surfaces. The study compares and analyzes the effects of laser power, defocus distance, and scanning speed on color outcomes and microstructure. Spectral analysis of the reflection spectrum is performed using a spectrometer, and energy-dispersive x-ray spectroscopy analyzes surface composition elements. The changes in the color gamut range are analyzed comparatively. This research investigates the influence of preheating on the coloring mechanism. The results indicate that, under preheating conditions, the stainless-steel surface exhibits better color uniformity, higher saturation, a broader color gamut, and a higher proportion of oxide components, which are primarily related to the increased initial laser absorption rate and reduced thermal conductivity due to preheating temperature.