Hard alloy is an alloy material formed by combining refractory metals and hard compounds with metals through powder metallurgy. Hard alloys have a series of excellent properties, such as high hardness, wear resistance, good strength and toughness, heat resistance and corrosion resistance, especially their high hardness and wear resistance. Even if they remain basically unchanged at 500 ℃, they still have high hardness at 1000 ℃. Compared with steel, alloy materials are difficult to cut, mainly manifested in the following aspects.
1. The trend of work hardening is significant
For example, the hardness of the matrix without GH4169 reinforcement is about HRC37. After being cut by a metal laser cutting machine, a hardening layer of about 0.03mm will be formed on the surface, and the hardness will be increased to HRC47, with a hardening degree of up to 27%. Work hardening has a significant impact on the service life of oxide taps, often leading to severe boundary wear.
Nickel based alloys are mainly composed of nickel and chromium, as well as a small amount of other elements such as molybdenum, tantalum, niobium, tungsten, etc. It is worth noting that tantalum, niobium, and tungsten are also the oxide tips of the main components (or high-speed steel) used in the manufacturing of hard alloys. When these oxide tips are used for the treatment of high-temperature alloys, diffusion wear and abrasive wear occur.
2. Poor thermal conductivity of materials
The fiber laser cutting machine generates a large amount of cutting heat when cutting high-temperature alloys, with cutting temperatures as high as 800-1000 ℃. Under the action of high temperature and high cutting force, the cutting edge of the tool will undergo plastic deformation, adhesion, and diffusion wear.
3. High cutting force
The strength of high-temperature alloy materials is more than 30% higher than that of ordinary alloy steel used in steam turbines. At cutting temperatures above 600 ℃, the strength of nickel based high-temperature alloys is still higher than that of ordinary alloy steels. The unit cutting force of non reinforced high-temperature alloy materials is greater than 4000N/square millimeter, while the unit cutting force of ordinary alloy steel is only 2500N/square millimeter.
For different materials, different equipment is often required for cutting. Although fiber laser cutting machines have many advantages, they are still not very suitable for any material.