the removal front 16 extends at an oblique angle also onto said removal front this can reliably be prevented when the beam spot of the radiation 15 and the jet spot of the combustible gas 12 do not overlap in this case the laser beam 23 will only cause preheating of the preheating section 13 the development of the removal process can also be influenced by the relative position of the laser beam spot and of the combustible gas jet spot the use of laser radiation outside of the hole 24 of the nozzle 20 for the combustible gas provides the possibility of adapting the nozzle 20 as well as the laser radiation 15 separately to the removal process in the best possible way an optimum adaptation of the nozzle 20 for the combustible gas will be achieved when the nozzle diameter s d has the following dimensions equ2 s d nozzle diameter s thickness of the steel plate this dimensioning is made clear by the representation shown in fig1 the variation range of parameter b is due to the fact that the nozzle diameter s d may decrease when the gas pressure increases the smallest nozzle diameters can be realized with supersonic nozzles fig3 to 5 show how an apparatus for removing material can be constructed in the best possible way when the preheating section 13 is preheated by a specially guided laser beam according to fig3 the laser radiation 18 39 of a radiation source 18 which is not shown is supplied to a beam splitter 26 which is a component part of a means 19 for preheating the surface 11 of the workpiece 10 the beam splitter 26 is a reflecting mirror provided with a hole a first larger component 26 39 being.