Laser cladding application field
Since the 1980s, laser cladding technology has developed rapidly and has become a hot spot in laser surface modification research at home and abroad. Laser cladding technology has great technical and economic benefits and is widely used in machinery manufacturing and maintenance, automobile manufacturing, textile machinery, marine and aerospace, and petrochemical industries.
The application of laser cladding is mainly in two aspects, namely corrosion resistance (including high-temperature corrosion resistance) and wear resistance, and the application range is wide, such as the sealing surface of the valve and valve seat of the internal combustion engine, water, gas or steam separator. Laser cladding, etc.
Laser-clad iron-based alloy powders are suitable for parts that require partial wear and are easily deformed. Nickel-based alloy powders are suitable for components requiring local wear resistance, heat corrosion resistance, and thermal fatigue resistance. Cobalt-based alloy powders are suitable for parts that require wear, corrosion and thermal fatigue resistance. Ceramic coatings have high strength at high temperatures, good thermal stability, and high chemical stability, and are suitable for parts requiring wear resistance, corrosion resistance, high-temperature resistance, and oxidation resistance.
Laser cladding development prospects
Laser cladding technology has achieved certain results and is in the initial stage of gradually moving towards industrial application. Future development prospects mainly include the following aspects:
- Design and development of cladding materials.
- Basic theoretical research on laser cladding.
- The establishment of a theoretical model.
- Improvement and development of Laser Cladding Equipment.
- Rapid prototyping technology for laser cladding.
- Automation of cladding process control.
Problems with laser cladding technology
The evaluation of the quality of the laser cladding layer is mainly considered from two aspects. First, macroscopically, the shape of the cladding road, surface irregularities, cracks, pores and dilution ratios were investigated. Secondly, on the microscopic level, it was investigated whether a good structure was formed and whether the required performance could be provided. In addition, the type and distribution of the chemical elements of the surface cladding layer should be determined. It is important to analyze whether the condition of the transition layer is metallurgical bonding and, if necessary, quality life testing.
The research work focuses on the development and development of cladding equipment, the kinetics of the molten pool, the design of the alloy composition, the formation of cracks, the expansion and control methods, and the bonding between the cladding layer and the substrate.
The main problems facing the further application of laser cladding technology are:
- Laser cladding process detection and implementation of automated control.
- The main reason why laser cladding technology has not yet fully realized industrialization in China is the instability of the quality of the cladding layer. During the laser cladding process, the heating and cooling speed is extremely fast, and the maximum speed can reach 1012 ° C / s. Due to the difference of temperature gradient and thermal expansion coefficient between the cladding layer and the base material, various defects may occur in the cladding layer. Mainly includes pores, cracks, deformation and surface irregularities.
- The cracking sensitivity of the laser cladding layer is still a difficult problem for researchers at home and abroad. It is also an obstacle to engineering application and industrialization. Although the crack formation has been studied, the control method is still immature.