Remote processing of metals with laser radiation with increased intensity

Application of laser radiation with a wavelength of 1.07 μm and intensity of ~104 W/cm2 used on damaged gas wells for remote cutting of metals can be inefficient on damaged oil wells owing to a large value of the mean coefficient of radiation absorption by the oil flame of ~0.1 cm–1. It was shown that, when the radiation with the intensity increased to 105 W/cm2 propagated through this flame, the absorption coefficient decreased rapidly and, in the intensity range of 105–106 W/cm2, it stabilized at a very low level of 5 × 10–3–10–2 cm–1. Experimental investigations on the conditions of remote cutting of metal plates from 1.5 to 60 mm in thickness by radiation of a cw ytterbium fiber laser with a power up to 7.5 kW at the radiation intensity of 105–106 W/cm2 on the metal surface were performed. It was found that, in a majority of practically important cases, such main parameters as drilling time, maximum cutting velocity, and cutting efficiency exceeded those at the radiation intensity of ≤104 W/cm2.