The Effect of Pulse Parameters on Intensity of Removal of Organic Layers from Carbon Steel and Other Materials During Pyrolysis Using Nanosecond Industrial Lasers

BACKGROUND: The article investigates pulsed laser cleaning (LC) technologies relevant for contemporary metalworking industries. AIM: To obtain new data for describing (at a semi-quantitative level) the relationship between LC output parameters and a set of adjustable operating parameters of these processes by experimental research of removing organic layers from metal samples using an up to 200 W pulsed laser, parametric analysis, and similar experimental data obtained earlier in similar studies with nanosecond lasers. METHODS: A series of experiments on LC of steel samples from paint films and a layer of rubber-containing contaminants (generated in tire production) was carried out with varying laser parameters and determining the LC performance, energy consumption, and some parameters affecting the destruction of the organic layer. RESULTS: An analysis of the results in combination with data from similar LC operations showed the complex multifactorial relationship between the input and the output operating parameters. In addition, it demonstrated that one of the most clearly (and directly proportional) parameters affecting the intensity of metal cleaning are the pulse duration tp and the duty cycle DC. In optimal conditions, the LC energy consumption is close to 13 MJ/(dm3 layer) in the LC option of elastomer-containing layer. In this LC option, the surface of St3 samples does not have noticeable erosion and its microhardness is approximately ≤ 180 HV, which is close to this parameter of the initial steel. CONCLUSION: In further RD, it will be advisable to select LC parameters based on the layer removal mechanism, which, according to preliminary estimates, in low energy consumption conditions comes with combination of energy-intensive thermal ablation (pyrolysis) and the coating exfoliation due to higher thermoelastic stresses in it.