Inconel

Inconel is a trademark of Special Metals Corporation for a series of corrosion- resistant nickel-base alloys. They are used primarily for high temperature applications. In English-speaking, they are often abbreviated with Inco. In addition to the trade names Inconel Chronin, Altemp, Haynes, Nickelvac and Nicrofer are common.

Composition

The individual products have different compositions. All have in common is nickel as the main component and chromium as an important secondary component. In addition, the following elements may be included: iron, molybdenum, niobium, cobalt, manganese, copper, aluminum, titanium, silicon, carbon, sulfur, phosphorus or boron

Properties

The alloys are resistant to corrosion, so that they are suitable for use in extreme environments. Upon heating, a thick, stable oxide layer that protects the surface is formed. The strength is maintained over a wide temperature range. This makes the alloy especially interesting for high temperature applications in which aluminum and steel are unstable.

Processing

Inconel alloys are considered difficult to process for classical deformation techniques as rapid hardening begins. In further forming steps, therefore, either the tool or the workpiece is deformed. For this reason, a high-performance, but slow the machine tool is mainly used, so that the number of required process steps is minimized. Alternatively, only the last process steps can be carried out cold. Threaded holes are realized by welding or soldering steel inserts with internal thread. The cutting is often carried out with a water jet cutting machine, also possible is the use of ceramic tool material. Welding is also a difficult due to cracking and separation of the alloy components in the vicinity of the weld. Further developments in the alloy formulation to fix this problem or mitigate. However, the most common way to deal with this is, the tungsten inert gas welding but also the electron beam welding process.

Applications

Inconel alloys are often used in areas with extremely high temperature stress. Compressor and turbine blades and combustion chambers in gas turbines are typical applications. Also possible is the use in turbochargers and exhaust valves as a material for the case of supercharged internal combustion engines. There they replace the sodium -filled exhaust valves. Because of the high price they come but only for tuning and motor sport in question. In Formula 1, inter alia, Inconel exhaust manifold are manufactured. Furthermore, in chemical reactors and boilers, as well as silencers in firearms. Frequent use will Inconel for example in reactors, nuclear reactors, piping and valves in the chemical and pharmaceutical industry. One application can be found here, for example, when processing contaminated with H2S and / or CO2 gas. Alternatives in chemical plant offer in addition to other nickel-based alloys and components made of unalloyed steel or fiberglass with a chemically resistant liner for example, perfluoroalkoxylalkane (PFA ), are lined. Also be used in practice enamelled components.

The outer skin of the aircraft missiles X -15 or some different parts of the Airbus A380 were also constructed with one of the alloys.