Classification, characteristics and applications of nickel-based alloy steel
Nickel-based alloy refers to a type of alloy with comprehensive properties such as high strength and certain oxidation and corrosion resistance at high temperatures of 650-1000℃. According to the main performance, it is subdivided into nickel-based high-temperature alloys, nickel-based corrosion-resistant alloys, nickel-based wear-resistant alloys, nickel-based precision alloys and nickel-based shape memory alloys.
1. Nickel-based high-temperature alloys
The main alloying elements are chromium, tungsten, molybdenum, cobalt, aluminum, titanium, boron, zirconium, etc. Among them, chromium plays an antioxidant and corrosion-resistant role, and other elements play a strengthening role. It has high strength and oxidation resistance and gas corrosion resistance at high temperatures of 650-1000℃. It is the most widely used and highest high-temperature strength alloy among high-temperature alloys. It is mainly used to manufacture high-temperature parts on aircraft engine blades and rocket engines, nuclear reactors, and energy conversion equipment
2. Nickel-based corrosion-resistant alloys
The main alloying elements are copper, chromium, and molybdenum. It has good comprehensive properties and can resist various acid corrosion and stress corrosion. The earliest application was nickel-copper alloy, also known as monel alloy; in addition, there are nickel-chromium alloy, nickel-molybdenum alloy, nickel-chromium-molybdenum alloy, etc. It is used to manufacture various corrosion-resistant parts.
3. Nickel-based wear-resistant alloy
The main alloying elements are chromium, molybdenum, tungsten, and also contain a small amount of niobium, tantalum and indium. In addition to wear resistance, it also has good oxidation resistance, corrosion resistance and welding properties. It can be used to manufacture wear-resistant parts, and can also be used as a coating material, which can be coated on the surface of other base materials through surfacing and spraying processes.
4. Nickel-based precision alloy
Including nickel-based soft magnetic alloy, nickel-based precision resistance alloy and nickel-based electric heating alloy. The most commonly used soft magnetic alloy is Permolite alloy containing about 80% nickel. It has high maximum magnetic permeability and initial magnetic permeability, low coercive force, and is an important iron core material in the electronics industry. The main alloying elements of nickel-based precision resistance alloy are chromium, aluminum and copper. This alloy has high resistivity, low resistivity temperature coefficient and good corrosion resistance, and is used to make resistors. Nickel-based electrothermal alloy is a nickel alloy containing 20% chromium. It has good anti-oxidation and anti-corrosion properties and can be used for a long time at 1000-1100℃.
5. Nickel-based shape memory alloy
Nickel alloy containing 50(at)% titanium. Its recovery temperature is 70℃, and its shape memory effect is good. A small change in the ratio of nickel and titanium can change the recovery temperature within the range of 30-100℃. It is mostly used to manufacture automatic opening structural parts used on spacecraft, self-excitation fasteners used in the aerospace industry, and artificial heart motors used in biomedicine.
Application fields of nickel-based alloy steel
The development level of the nickel-based alloy industry is in a steady upward trend. Nickel-based alloys with different compositions and properties have been increasingly widely used with the development of industry. Its main application fields are:
1. Ocean: marine structures in marine environment, seawater desalination, seawater aquaculture, seawater heat exchange, etc.
2. Environmental protection field: flue gas desulfurization equipment for thermal power generation, wastewater treatment, etc.
3. Energy: atomic power generation, comprehensive utilization of coal, tidal power generation, etc.
4. Petrochemical: oil refining, chemical equipment, etc.
5. Food: salt production, soy sauce brewing, etc.
