The application of laser cutting in the cutting of carbon steel plate can be said to have been common, and its processing principle is to conduct hot working through high-density laser beam. As a type of processing technology, various technical problems may arise during laser cutting of carbon steel, with black edge problems being a common one. What are the reasons for laser cutting carbon steel black edges and how can we avoid them? Let’s take a look together.
Analysis of the Causes of Black Edges in Laser Cutting of Carbon Steel
The fundamental reason for the appearance of black edges in laser cutting of carbon steel is the output of heat during the laser cutting process. The metal material itself has good thermal conductivity. Generally speaking, the heat generated during the cutting process diffuses through the cutting gaps and is slowly cooled in the metal plate. However, due to differences in physical properties such as metal material and density, the outer side of the hole body can be fully cooled during laser cutting of carbon steel, However, the residual part on the inner side of a single hole is too narrow in the space where heat can diffuse, resulting in the inability of heat to diffuse in a timely manner, leading to the accumulation of black edges and even the occurrence of slag. In addition, during the laser cutting process of thick metal plates made of carbon steel, the accumulation of molten metal and heat on the surface caused by drilling can cause turbulence in the auxiliary airflow, resulting in excessive heat input within a certain period of time, leading to black edges.
Solution to Black Edges in Laser Cutting of Carbon Steel
The key to solving the black edge problem in traditional carbon steel cutting methods that rely on oxygen as an auxiliary gas is to effectively suppress the generation of oxidation reaction heat. In this case, the cutting method can be completed by using auxiliary oxygen during perforation and lagging to switch to auxiliary air or nitrogen. The maximum thickness that can be processed by this method is a small hole with a thickness of one-sixth of the plate. When laser cutting carbon steel, the pulse cutting conditions with high peak and low frequency output power can reduce the characteristics of heat output, which will be conducive to optimizing the cutting conditions. The cutting conditions can be set to a single pulse laser beam, high energy intensity peak output, and low frequency specifications. This will effectively reduce the accumulation of molten metal during the laser piercing process, thereby effectively suppressing the output of heat and reducing the occurrence of black edge phenomenon.
