Apr 14, 2020
Because of its high hardness and high-temperature resistance, it is difficult to ensure cutting accuracy when using a metal laser cutting machine. So, what are the difficulties of using fiber laser cutting machines to process high-temperature aluminum alloy compared with general steel? Its main performance is as follows:
1. The tendency of work hardening is large. For example, the hardness of the GH4169 unreinforced matrix is about hrc37. After cutting by a laser cutting machine, a hardening layer of about 0.03mm will be produced on the surface. The hardness will increase to about hrc47, and the hardening degree will be as high as 27%. The work hardening phenomenon has a great influence on the life of the oxidation tip tap, which usually results in serious boundary wear.
2. Poor thermal conductivity of materials. When cutting superalloy, a large amount of cutting heat is borne by the oxidation tip tap, and the cutting temperature of cutting tip is up to 800-1000 ℃. Under the action of high temperature and large cutting force, the cutting edge will produce plastic deformation, adhesion, and diffusion wear.
3. Large cutting force. The strength of the superalloy is more than 30% higher than that of common alloy steel for steam turbines. At the cutting temperature above 600 ℃, the strength of the nickel-base superalloy is still higher than that of common alloy steel. The unit cutting force of the unreinforced superalloy is more than 4000N / mm2, while that of the ordinary alloy steel is only 2500n / mm2.
4. The main components of the nickel-base alloy are nickel and chromium. In addition, a small number of other elements are added: molybdenum, tantalum, niobium, tungsten, etc. it is worth noting that tantalum, niobium, tungsten, etc. are also the main components used to make oxidation tip taps of cemented carbide (or high-speed steel). Processing high-temperature alloy with these oxidation tip taps will produce diffusion wear and abrasive wear.