The high-speed steel cutting tool has become a tool widely used in the machining industry because of its good machinability, but when processing some materials with higher hardness, the cutting temperature is often very high (about 1000 ° C), and the high-speed steel annealing temperature is generally about 860~880 ° C, so it will lead to a decrease in hardness and can not meet the processing requirements. In the cutting process, the cutting tool not only withstands the impact and the vibration load, but also affected by the workpiece and the chip of the strong friction, which results in appearance wear, rolling edge, falling edge or break phenomenon of the high-speed steel tools during the using . It will affect the processing accuracy and production efficiency and shorten the service life of the tool, while increasing the cost of production.
Laser cladding technology has been a rapidly developed material surface modification technology in recent decades. It has the excellent characteristics that many conventional technologies cannot reach, such as low working environment requirements, small deformation of the workpiece after processing, high hardness surface modification layer, which is suitable for processing in local areas and difficult-to-access areas. Therefore, it is being paid attention to by more and more research institutions and enterprises. It has been used to improve the performance of conventional cutting tools by coating a cermet layer on the surface of cutting tools with laser technology.
At present, the commonly used high-speed steel tools are generally integral, and can only be scrapped when the blade belt is worn, so the material waste of the tool is relatively high and the manufacturing cost is high. The laser cladding technology only needs to strengthen the cutting-edge belt of the tool by presetting cladding materials at the cutting edge of the tool. Due to the small cladding area, precious metal materials can be saved, thus reducing the manufacturing cost. At the same time, the cutting edge of the cutting tool after cladding has high strength, hardness and wear resistance, but also has the strength and toughness of the matrix, which better solves the contradiction between the hardness and strength and toughness of the high-speed steel tool, and improves the cutting performance of the high-speed steel tool.
In laser cladding processing, the main problem is that the cladding layer is prone to crack. The main mechanism is that the internal stress is formed when the cladding layer is constrained by the matrix during cooling and curing. Cracks occur when the local internal stress exceeds the strength limit of the material. The temperature gradient between the cladding layer and the substrate can be reduced by preheating and post-heat treatment of the high-speed steel tool, and some bonding components such as Co, Mo and rare earth are added to the alloy powder. The addition of Co and Mo can improve the wettability of the alloy and help reduce the thermal shrinkage stress of the cladding layer during the condensation process. Rare earth makes the microstructure of the alloy layer finer, improves the toughness, and thus reduces the crack. In addition, optimizing the alloy powder formulation and laser process parameters using nano-composite powders can improve the performance of the cladding layer and reduce the tendency to crack.
The surface strengthening treatment of the cutting tools is one of the important ways to improve tool wear resistance and service life. Combining the advantages of laser cladding technology with the requirements of high-speed cutting tools and high-speed steel tools can have excellent cutting performance such as wear resistance, heat resistance, corrosion resistance, high temperature oxidation resistance and high red hardness. In addition, while obtaining a high-performance cutting edge and the strength and toughness of the matrix, the cutting edge of the tool is better protected during processing, and the contradiction between the hardness and toughness of the high-speed steel tool is effectively solved. Less powder material is consumed in the processing of laser cladding high-speed steel cutting tools, reducing the demand for precious rare metal materials, which meet the requirements of energy saving and environmental protection. The process is simple, less equipment is required, and it is easy to realize automation. With the continuous development of cutting technology, it can be predicted that laser cladding technology will have an important impact on the performance improvement of high-speed steel cutting tools.
Xi'an Guosheng Laser Technology Co., Ltd. is a high-tech enterprise specializing in R&D, manufacturing and sales of automatic laser cladding machine, high-speed laser cladding machine, laser quenching machine, laser welding machine and laser 3D printing equipment. Our products are cost-effective and sold domestically and abroad. If you're interested in our products, please contact us at bob@gshenglaser.com.