Nickel Base Alloys and Their Castings by Investment Casting
Nickel-based alloy refers to a high alloy with nickel as the matrix (generally greater than 50%) and copper, molybdenum, chromium and other elements as alloying elements. The main alloying elements of nickel-based alloys are chromium, tungsten, molybdenum, cobalt, aluminum, titanium, boron, zirconium and so on. Among them, Cr, Al, etc. mainly play an anti-oxidation effect, and other elements have solid solution strengthening, precipitation strengthening and grain boundary strengthening. Nickel-based alloys mostly have austenitic structure. In the state of solid solution and aging treatment, there are also intermetallic phases and metal carbonitrides on the austenite matrix and grain boundaries of the alloy.
Nickel-based alloys have high strength and good oxidation resistance, corrosion resistance and high temperature resistance in the range of 650 to 1000°C. Nickel-based alloy is a common high-temperature resistance alloy. Nickel-based alloys are subdivided into nickel-based heat-resistant alloys, nickel-based corrosion resistant alloys, nickel-based wear-resistant alloys, nickel-based precision alloys and nickel-based shape memory alloys according to their main properties. Nickel-based superalloys, iron-based superalloys and nickel-based superalloys are collectively referred to as high-temperature alloys. Therefore, nickel-based superalloys are referred to as nickel-based alloys. Nickel-based superalloy series materials are widely used in aviation, aerospace, petroleum, chemical, nuclear energy, metallurgy, marine, environmental protection, machinery, electronics and other fields. The grades and heat treatment methods selected for different mechanical parts will be different.
Nickel-based alloys are generally cast through an investment casting process. The common grades of nickel-based alloys for casting are as follows:
- Ni-Cr-Mo alloy, Hastelloy series C-276, C-22, C-2000, C-4, B-3
- Ni-Cr alloy: Inconel 600, Inconel 601, Inconel 625, Inconel 718, Inconel X 750, Incoloy 800, Incoloy 800H, Incoloy 800HT, Incoloy 825;
- Ni-Cu alloy, Monel 400, Monel K500