Superalloys are the more common materials in our processing, so can it be processed using fiber laser cutting machines? Let's take a look at the "difficulties in processing high-temperature alloys by fiber laser cutting machines".
The first thing to introduce to you is the processing principle of the fiber laser cutting machine: the laser light emitted by the laser is focused by the lens, and is concentrated into a small spot at the focus. The workpiece at the focus is illuminated by the laser spot with high power density. It will produce a local high temperature above 10000 °C so that the workpiece will be vaporized instantaneously, and then the vaporized metal will be blown away with the auxiliary cutting gas. With the movement of the CNC machine tool, the cutting purpose is achieved.
Because of its high hardness and high-temperature resistance, high-temperature alloys are difficult to guarantee accuracy when using laser cutting. Therefore, the main performance of high-temperature aluminum alloys compared with general steel products using fiber laser cutting machines:
1. The work hardening tendency is large. For example, the hardness of the substrate of GH4169 unreinforced is about HRC37. The surface of the metal laser cutting machine will produce a hardened layer of about 0.03mm, and the hardness will increase to about HRC47, and the hardening degree is as high as 27%. Work hardening has a large effect on the life of the oxidized tip tap and often results in severe boundary wear.
2. The material has poor thermal conductivity. A large amount of cutting heat generated when cutting high-temperature alloys is absorbed by the oxidation tip taps, and the cutting edge is subjected to cutting temperatures of up to 800-1000 ° C. Under high temperature and large cutting force, the cutting edges will be plastically deformed, bonded and diffused.
3. Large cutting force. The strength of superalloy is more than 30% higher than that of conventional alloy steel of steam turbine. Under the cutting temperature of above 600 °C, the strength of nickel-based superalloy is still higher than that of ordinary alloy steel. The unit cutting force of the unreinforced high temperature alloy is above 4000 N/mm2, while the ordinary alloy steel is only 2500 N/mm2.
4. Nickel-based alloys are mainly composed of nickel and chromium, and a small amount of other elements are added: molybdenum, niobium, tantalum, tungsten, etc. It is worth noting that tantalum, niobium, tungsten, etc. are also used to make hard alloys (or high speed). Steel) The main component of oxidized apex taps. The use of these oxidized tip taps to process superalloys produces diffusion wear and abrasive wear.