Laser remanufacturing promotes the upgrading and transformation of steel plant equipment

　　Laser surface hardening technologies usable in steel enterprises mainly include laser cladding, laser surface alloying, and laser surface quenching.

　　01 Laser Surface Quenching

　　Laser surface quenching does not require changing the material composition. It uses the characteristics of rapid local heating and cooling by the laser beam to cause a martensitic phase transformation on the material surface to achieve the purpose of strengthening. This can be divided into laser phase transformation quenching and laser melting quenching.

　　02 Laser Cladding

　　Laser cladding technology uses a laser beam to clad a coating with special properties on the specified surface of a workpiece to improve the surface performance of the workpiece. It is divided into pre-placed powder method and simultaneous powder feeding method, generally using added alloy powder to complete laser cladding. Compared with traditional spraying or welding processes,

　　03 Advantages of Laser Cladding Technology:

　　(1) The laser beam has high energy density, the coating dilution rate is relatively low, the heat affected zone of the component is small, and the deformation is small, suitable for strengthening or repairing high-precision parts or parts with strict deformation requirements.

　　(2) By optimizing the selection of cladding materials, the composition and performance of the cladding layer can be precisely controlled, with a wide range of materials and strong applicability.

　　(3) The fine, uniform, and dense microstructure formed by rapid cooling in laser cladding, and the strong metallurgical bonding, allow its application in surface strengthening and repair of parts under heavy load conditions, such as transmission shafts or rolling mills in steel plants.

　　(4) The size and position of the laser cladding layer can be precisely controlled by automated operation. The multi-pass overlapping method is used to realize large-area and large-thickness laser cladding on the workpiece surface to meet the laser surface strengthening and repair of mechanical equipment parts with different shapes and sizes.

　　Laser Surface Alloying

　　The laser surface alloying process is similar to the laser cladding process, changing the composition, microstructure, and properties of the workpiece surface by adding alloying elements. However, in the former, the added alloying elements melt with the substrate and fully mix, cooling and solidifying to form a new surface layer; both together determine the properties of the surface layer; whereas in laser cladding, the properties are mainly determined by the added alloy powder, with minimal contribution from the substrate. Therefore, the dilution rate should be minimized during laser cladding.