Hardening is a kind of surface heat treatment applied to steel parts, which can greatly enhance the hardness of steel parts. The Basque University (UPV/EHU) High-Performance Manufacturing Research Group researched and fine-tuned an innovative technology to arrive at this set of processes. It involves the use of lasers, but unlike traditional systems, it uses scanning optics, which allows it to have a great degree of flexibility in the thickness of the processed parts.
The hardness of steel can be achieved by hardening, which is essential for steel parts that require high wear resistance, such as steel plate stamping dies. First carry out a heating process up to 800-1000oC, and then carry out rapid cooling. This will change the structure of the steel.
If hardening is carried out by laser pointer, because it is a highly localized heat source, it will make only the surface hardened, while leaving the core of the part in its original state; thus making the part less brittle, and because it acts on There is less heat on the top, and the distortion of the part will be much less. Finally, the effect of heat will deform the part, which means that it must be surface treated by other methods in the end. He is a professor in the Department of Mechanical Engineering at the University of Basque and a member of the High Performance Manufacturing Research Group that performed this research. In the industry, the laser hardening process has been used since 2000. However, according to Lamikiz, it has a limitation: the laser scans with a constant bandwidth, so the thickness of the resulting hardened zone is also constant.
A test part that uses scanning optics to perform laser hardening. In order to make the technology more flexible, the research team at the University of Basque Country decided to evaluate the feasibility of using moving scanning optics in the process. The optical system (galvanometer scanner) they used is to move a very small laser at a very fast speed, scanning the surface line by line.
In this way, the hardening width can be adjusted simply by changing the program parameters. By comparing the hardening process with painting a wall, traditional laser hardening is like painting a wall with a roller, so the width of the brush corresponds to the width of the roller. Instead, in this new technology, we replaced the roller with a marker pen with the finest nib.
In the experiments they conducted, the first thing they discovered was that it is possible to use this technique for hardening. Then, we gradually saw how the result of the heat treatment changes with the green laser pointer moving speed, the power used, etc. According to our test, when the laser moves very fast, the result is similar to the traditional process .