On Energy Efficiency Characteristics of Laser Erosion on Oxidic Surfaces of Carbon Steels, Cast Iron and Low-alloy Non-ferrous Alloys During Deoxidizing Cleaning. Part II

An analysis of the energy efficiency characteristics was performed for laser erosion cleaning (LC) processes developed last period for the application in metalworking sector for the wide group of carbon steels, cast iron and non-ferrous metal alloys to remove surface oxidic layers. The consideration of some characteristics of the LC-processes (energy consumption, energy criterion K en1s et al.) gives the opportunity for the evaluation of the effects of different mechanisms of the surface deoxidizing during the pulsed laser cleaning of MeO x -layers. Analysis of LC-processes taking into account the efficiency characteristics was based on the massive of parameters of typical (in the field of LC of oxides) regimes of processing of samp-les of carbon steels with surface oxide layers (including using data from our experiments) with use of various pulsed lasers, as well as some samples of aluminum, copper and titanium alloys and cast iron with surface oxides. Our comparison of estimated values of the parameters for a number of recent LC-variants demonstrates that it can be supposed with a sufficient reliability that for the most typical LC-processing cases (preliminary studied in our experiments with cleaning steel samples from mill scale and also described for LC-processes with removal of oxides from some non-ferrous alloys), the first, i.e. the most energy-consuming (thermal ablation with heating to the melting temperature or even higher) of the cleaning mechanisms is more probable. For this processing group the level of the energy criterion values achieved in our experimental series with the LC of FeO x -scale ( K en1s ≈ 4.4 and corresponding approximate value can, according to our kinetic estimates, be considered close to the threshold level, below which not only the LC thermal ablation will be realized in parallel, but also partially the other two deoxidizing mechanisms (not so high energy consumed ones). At the same time active realization of other, i.e. non-ablative mechanisms is feasible in a rarer group of LC-operating cases (e.g. in the laser removal of TiO x -film from the titanium alloy, and also, possibly, in the regime of alumina removal from aluminium alloy for which the K en1s level is probably equivalent to the “transition zone” with substantial contribution of both non-ablative mechanisms and thermal ablation).