Laser Surface Additive Manufacturing

In coal mining, the sprocket of the coal shearer is a key component of the traction system of the coal shearer. By meshing with the chain on the scraper conveyor, the coal shearer moves along the scraper conveyor, achieving the walking traction of the coal shearer. Due to long-term meshing transmission with the chain and the friction and impact from coal blocks, rocks, etc. during the coal mining process, the teeth of the sprocket are prone to wear. Wear can cause changes in the tooth profile of the gear teeth, increase the meshing clearance, and affect the traction performance of the coal shearer. Meanwhile, in the damp and dusty environment of underground coal mines, sprockets are prone to corrosion. Corrosion will reduce the strength and wear resistance of the sprocket and shorten its service life. Under harsh working conditions such as heavy load and impact, the teeth of the sprocket may break, etc. To further enhance the wear resistance and corrosion resistance of the sprocket, surface treatment is usually carried out on the sprocket. A hardened layer with high hardness can be formed on the surface of the sprocket, which can improve the wear resistance and fatigue resistance of the teeth, and also enhance the corrosion resistance of the sprocket and extend its service life. Laser cladding technology, as an advanced surface modification technique, has significant applications in fields such as the repair and processing of coal mining machine sprockets. It can precisely control the thickness and shape of the cladding layer, accurately restore the original size and precision of the sprocket, and ensure the fit accuracy between the sprocket and other components.

The application advantages in the repair of sprockets of coal mining machines

Restoring dimensional accuracy: During the operation of the sprocket of the coal mining machine, due to wear and other reasons, the dimensional accuracy may decline. Laser cladding technology can precisely deposit a layer of metal material on the worn area, restoring the size of the sprocket to the design requirements and ensuring its good meshing with the chain.

Enhancing wear resistance: By choosing appropriate wear-resistant cladding materials, such as alloy powders containing hard phases like tungsten carbide and chromium carbide, laser cladding can form a high-hardness and highly wear-resistant cladding layer on the surface of the sprocket, significantly improving its wear resistance and extending its service life.

Repairing complex shapes: The teeth of the sprocket of the coal mining machine have complex shapes. Laser cladding technology can precisely carry out local repairs based on the specific shape and wear condition of the sprocket. For some complex-shaped parts that are difficult to handle with traditional repair methods, it can also achieve good repair results.

Reduce maintenance costs: By using laser cladding to repair the sprocket of the coal mining machine, there is no need to replace the entire sprocket. Only the worn parts need to be repaired, which greatly reduces maintenance costs and replacement cycles. Meanwhile, due to the significant improvement in the performance of the sprocket after laser cladding, the subsequent maintenance frequency and downtime have been reduced, thereby enhancing the efficiency and economic benefits of coal mining production.

Laser cladding processing technology flow

Pre-treatment (Cleaning, degreasing and rust removal of the chain teeth surface to remove oil stains, impurities and oxides on the surface to ensure surface cleanliness.) The surface of the chain teeth is roughened by mechanical processing or grinding to increase the surface roughness and enhance the adhesion between the cladding layer and the substrate.

Powder selection (Select the appropriate alloy powder based on the working conditions and performance requirements of the chain teeth.) Commonly used powders include nickel-based, cobalt-based, iron-based and other alloy powders. Elements such as tungsten, chromium and molybdenum can be added to enhance the hardness, wear resistance and corrosion resistance of the cladding layer.

Laser cladding (Fix the chain teeth on the workbench and adjust the parameters of the laser cladding equipment, including laser power, scanning speed, spot diameter, powder feeding volume, etc.) Start the laser cladding equipment, focus the laser beam on the surface of the chain teeth, and at the same time, evenly send the alloy powder into the laser action area through the powder feeder. Under the high-temperature effect of the laser, the powder rapidly melts and fuses with the base material on the surface of the chain teeth to form a cladding layer. According to the pre-determined scanning path, cladding is carried out point by point or line by line until the entire surface of the chain teeth is fully cladding. Post-treatment (Heat treatment of the chain teeth after cladding, such as tempering and aging, etc., to eliminate residual stress in the cladding layer and improve the microstructure stability and performance of the cladding layer.) The surface of the chain teeth is precisely processed by mechanical processing methods such as grinding and polishing to ensure that the size and surface roughness of the chain teeth meet the design requirements.

Optimization of laser process parameters

Laser power: Laser power is one of the key parameters that affect the quality of the cladding layer. If the power is too low, the powder cannot be fully melted, which will result in low bonding strength and high porosity of the cladding layer. Excessive power will cause excessive melting of the substrate, resulting in an increase in the dilution rate of the cladding layer and affecting the performance of the cladding layer. Generally, the appropriate laser power is selected based on the material, size of the chain teeth and the thickness requirements of the cladding layer.

2. Scanning speed: The scanning speed determines the time and energy input of the laser acting on the surface of the chain teeth. The scanning speed is too fast, the powder is not melted sufficiently, and the thickness of the cladding layer is uneven. If the scanning speed is too slow, it will cause the substrate to overheat, leading to deformation and deterioration of the structure.

3. Powder feeding volume: The powder feeding volume should be matched with the laser power and scanning speed. If the powder feeding amount is too large, the powder cannot be completely melted and inclusions will form in the cladding layer. If the powder feeding amount is too small, it will result in insufficient thickness of the cladding layer.

Advantages of Guosheng Laser's laser cladding technology

1. Stable processing quality: With 15 years of experience in laser cladding repair, we have accumulated numerous laser cladding process parameter packages in multiple fields such as aerospace, mechanical processing, mold manufacturing, and the steel industry, ensuring stable processing quality

2. Innovative R&D team: Continuously innovating research processes to provide you with high-quality product processing and maintenance solutions

3. Improve services: 7x24-hour pre-sale and after-sale services