THE PROPERTIES OF CAST IRON SURFACE LAYERS MODIFIED BY LASER ABLATION MICROMACHINING

Abstract

The article presents the results of model laboratory tests, including the measurement of temperature, friction force, and linear wear of the surface layer of samples made of grey cast iron sliding against a steel counterpart. The surface layer of the cast iron specimen was modified using ablative laser micromachining in order to change its macro- and micro-geometry. To produce regular oil micro-reservoirs in a shape of micro-channels, an Nd: YAG laser (λ = 1064 nm, ƒ = 1 – 100 kHz, E = 50 J, P = 50W) with a special focusing system was used. Comparative studies included a grey cast iron specimen subjected to conventional mechanical machining and a specimen modified by ablative laser micromachining. 41Cr4 steel with a hardness of 50 HRC was used as a counterpart. Tribological tests were run in a pin-on-disk (T-11 tribometer) test set-up. The best results in the reduction of friction, temperature, and wear were obtained for samples with oil micro-reservoirs (made of ablative laser texturing) in a shape of micro-channels covering 5% of the entire tribological contact surface.