Huirui has completed several on-site laser repair cases of rolling mill arches. At present, Huirui’s technology and use effect of laser cladding repair of rolling mill arches have been generally recognized by steel company customers, solving long-standing repair problems for customers.

Rolling mill arch processed by laser remanufacturing technology:

• Restore the shape and size of the damaged part;
• Improved hardness and wear resistance, thereby increasing service life, guaranteed to be used for 8-10 years;
• Reduced costs of purchasing new products;
• The movable repair can achieve rapid repair and save time for the annual maintenance of steel plants;
• It can also make its corrosion resistance reach or even exceed the level of new products.

1. Project background

During the steel production process, the working conditions of hot rolling machinery and equipment are very harsh. Especially during the operation of the rolling mill, the rolling cooling water quickly atomizes when encountering the red-hot steel billet, entraining the iron oxide powder that falls off the surface of the billet and sprays it around. , the roll passes through the bearing seat and causes a large impact on the frame arch, causing different corrosion and wear on the inner window surface of the rolling mill frame arch and the bottom surface of the frame arch, making it difficult to effectively control and manage the gap between the rolling mill frame and the roll bearing seat. The gap between the rolling mill stand and the roll chock exceeds the management limit.

The increase in the gap between the rolling mill arches worsens the working conditions of the main drive system of the rolling mill, causing the main drive to vibrate and impact greatly. It is easy to slip when the steel ingot bites in, which affects the control of the plate shape and has a great impact on product quality. The rolling mill archway is bulky and difficult to disassemble and transport, and the cost of returning it to the factory or replacing it with a new one is extremely high. Therefore, a suitable online repair method for the window surface of the rolling mill archway is needed.

2. Laser cladding

Laser cladding can be used to perform in-situ dimensional restoration and surface strengthening on the surface of the rolling mill arch. Compared with other methods, the laser cladding repair method of rolling mill arches has the following main advantages:

• This technology takes advantage of the small, flexible, and convenient features of light lasers and is suitable for online repair. Compared with manual arc surfacing welding, the labor intensity is greatly reduced, and the process stability and coating quality are improved.
• The heat input during laser cladding is small and the cladding layer is thin, which has little impact on the overall structure of the rolling mill arch and does not bring the risk of deformation of the arch.
• Laser cladding uses coating materials with good anti-corrosion and wear resistance properties, which completely changes the characteristics of the arch surface. The coating life is expected to be more than ten years, avoiding the harm caused by frequent machining and repair of the arch surface.
• The coating after laser cladding is very smooth and requires no subsequent processing, saving repair time and costs.

3. Rolling mill repair site

• Laser tracker:
  Used for laser inspection of archways to more accurately detect the overall status of the archway and confirm the benchmark for repair processing.
• Online CNC machining boring and milling mobile facade machine tools:
  Archway’s online processing equipment
• On-site movable laser cladding equipment performs laser cladding on the rolling mill surface.
• Finishing the arch surface after cladding
• Huirui powder feeder:
  Huirui has developed a high-precision powder feeder to meet the requirements for on-site high-quality repair of high-end power equipment components. It realizes the function of multi-channel large-capacity uninterrupted powder feeding. The accuracy of the powder feeding amount can be controlled at <1%, ensuring that the laser Process stability of cladding for long-term field operations.
• Huirui laser head:
  In view of the requirements for accessibility, flexibility, and stability of cladding processing in the narrow space of the archway machine base, the small laser head developed by Huirui is flexible and convenient and is durable and reliable in harsh on-site environments.
• Huirui nozzle:
  The four-point nozzle developed by Huirui can ensure accurate and stable powder flow at different angles, meeting the powder feeding requirements for on-site 360-degree all-round repair.