Technology of laser cleaning of steel structures

Abstract

Cleaning metal surfaces from oxide films, corrosion products, scale and other contaminants to obtain the required quality is one of the basic technologies in many industries. There are traditional methods of cleaning, which in the process of their evolutionary development and improvement have approached the potential technological frontier and do not fully meet the ever-growing demands of the industry. An alternative method is laser cleaning. Goal. The aim is development of modes for laser cleaning of steel structures from rust and technological contamination, which can be used both in stationary and field conditions. Method. To clean the steel structures, we used an installation based on a pulse-periodic CO2 laser with a power of 130 W. To assess the quality of the surface layer, the microhardness method and roughness measurement were used. Results. Under the action of laser radiation on the oxidized surface, reactions of reduction of oxides and evaporation of paint and varnish contaminants occur. The influence of the radiation power and the number of passes during cleaning on the surface quality, which was evaluated by the degree of metallization and roughness, was investigated. Scientific novelty. It was determined that the position of the focal plane above the surface and on the surface is the optimal position of the laser radiation for cleaning. It was found that the microhardness of the surface layer of steel after normalization and after metallization of the surface in the process of laser cleaning is practically the same. It is shown that preliminary wetting of the surface during cleaning from rust using a CO2 laser is not advisable. Water vapor is especially strong in absorbing waves in the infrared range, and carbon dioxide is an intense absorber in the mid-infrared range. Practical significance. Recommendations have been developed for the use of a repetitively pulsed CO2 laser for cleaning the steel structures of bridges, power lines, towers of television and mobile transmitters from rust and technological contamination in field conditions.