The application of laser cutting in carbon steel plate cutting can be said to have been common. Its processing principle is to carry out thermal processing through high-density laser beam. As a kind of processing technology, there are various technical problems in the process of laser cutting carbon steel, and the black edge problem is a common one. Where are the reasons for laser cutting carbon steel black edges and how to avoid them? Let's have a look.
Cause analysis of black edge in laser cutting carbon steel
The root cause of black edges in laser cutting carbon steel is the output of heat in the process of laser cutting. The thermal conductivity of the metal material itself is very good. Generally speaking, the heat generated in the cutting process will spread through the cutting gap and be slowly cooled in the metal plate. However, due to the different physical properties such as metal material and density, the outside of the hole body can be fully cooled in the small hole processing of laser cutting carbon steel, However, the residual part inside the single hole has too narrow space for heat diffusion, which leads to the lack of timely diffusion of heat and agglomeration, resulting in black edge phenomenon and even slag hanging. In addition, in the process of laser cutting carbon steel thick metal plates, due to the metal melt and heat accumulation on the surface of the material caused by punching, the auxiliary air flow will be disordered, and the heat input will be excessive within a certain period of time, resulting in black edges.
Solution of black edge in laser cutting carbon steel
In the traditional carbon steel cutting method using oxygen as auxiliary gas, the key to solving the black edge problem is to effectively inhibit the generation of oxidation reaction heat. In this case, the cutting method can be completed by using auxiliary oxygen during perforation and switching to auxiliary air or nitrogen after delay. The maximum thickness that can be processed by this method is the small hole of one sixth of the thickness of the plate. When laser cutting carbon steel, the pulse cutting conditions of high peak and low-frequency output power can reduce the characteristics of heat output, which will be conducive to the optimization of cutting conditions. The cutting conditions can be set as a single pulse laser beam, high peak output of energy intensity and low-frequency specification, which will effectively reduce the accumulation of metal melt in the process of laser perforation, and then effectively inhibit the output of heat and reduce the generation of black edge phenomenon.