Although almost all metallic materials have high reflectivity of infrared energy at room temperature, CO2 lasers emitting at a far-infrared 10.6-μm beam have been successfully used in many metal laser cutting practices. The initial absorption rate of metal for a 10.6 μm laser beam is only 0.5% to 10% However, when a focused laser beam having a power density exceeding 106 W / cm 2 is irradiated onto the metal surface, it can be quickly applied in a microsecond period The surface begins to melt. Absorption of most metals in the molten state increases sharply, generally up to 60% ~ 80%. 
Modern laser cutting system can cut carbon steel up to a maximum thickness of 20MM The use of oxidation and melting cutting mechanism cutting carbon steel can be controlled within a satisfactory range of width of the slit sheet can be narrow to about 0.1MM.
Laser cutting is an effective tool for the manufacturing industry that uses stainless steel sheet as the main component. Strict control of the heat input during the laser cutting process can limit the heat-affected zone becomes very small , which is very effective to maintain the good corrosion resistance of such materials 
Most of the alloy steel and alloy tool steel can use laser cutting method to obtain good cutting quality. Even for high-strength materials, flat, non-slag-cut edges are available as long as process parameters are properly controlled. However, for tungsten-containing high-speed tool steels and hot-gauge steels 熔 Laser cutting and fusing may occur.
Aluminum and alloy
Aluminum cutting belongs to the melt-cutting mechanism 辅 The auxiliary gas used is mainly used to blow away the molten product from the cutting zone , usually to obtain better quality of the cut surface. For some aluminum alloys, care should be taken to prevent the generation of microcracks between the surfaces of the kerf.