METHOD FOR CUTTING C-Mn STEEL WITH A FIBER LASER

Abstract

The invention relates to a laser cutting method for cutting a C-Mn steel workpiece, characterized in that laser beam generation means comprising at least one silica fiber with an ytterbium-doped core is used to generate the laser beam. Preferably, the ytterbium-based fiber has a wavelength between 1.07 and 1.1 μm, preferably 1.07 μm, the quality factor of the laser beam is between 0.33 and 8 mm.mrad, and the laser beam has a power of between 0.1 and 25 kW. The assistance gas for the laser beam is chosen from nitrogen, helium, argon, oxygen, CO 2 and mixtures thereof, and, optionally, it further contains one or more additional compounds chosen from H 2 and CH 4 .

1 . A laser cutting method for cutting a C-Mn steel workpiece, wherein laser beam generation means comprising at least one ytterbium-containing fiber for generating a laser beam and in that the quality factor of the laser beam is between 0.33 and 8 mm.mrad.  
   
   
       2 . The method of  claim 1 , wherein said fiber is formed from an ytterbium-doped core clad with silica.  
   
   
       3 . The method of  claim 1 , wherein said laser beam generated by the ytterbium-based fiber has a wavelength between 1 and 5 μm, preferably between 1.04 and 3 μm.  
   
   
       4 . The method of  claim 1 , wherein said laser beam generated by the ytterbium-based fiber has a wavelength between 1.07 and 1.1 μm, preferably of 1.07 μm.  
   
   
       5 . The method of  claim 1 , wherein said laser beam has a power of between 0.1 and 25 kW, preferably between 0.5 and 15 kW.  
   
   
       6 . The method of  claim 1 , wherein said laser beam is a continuous or pulsed laser beam, preferably a continuous laser beam.  
   
   
       7 . The method of  claim 1 , wherein the workpiece to be cut has a thickness between 0.25 and 30 mm, preferably between 0.40 and 20 mm.  
   
   
       8 . The method of  claim 1 , wherein said cutting speed is between 0.1 and 20 m/min, preferably from 1 to 15 m/min.  
   
   
       9 . The method of  claim 1 , wherein the assistance gas for said laser beam is selected from the following group: 
 a) nitrogen;    b) helium;    c) argon;    d) oxygen; and    e) CO 2  and mixtures thereof; and    f) optionally, said gas further contains one or more additional compounds chosen from H 2  and CH 4 .    
   
   
       10 . The method of  claim 1 , wherein the quality factor of said laser beam is between 1 and 8 mm.mrad, preferably greater than 2 mm.mrad, even more preferably greater than 3 mm.mrad and/or preferably less than 7 mm.mrad and even more preferably less than 5 mm.mrad.