Inconel is a special metals corporation registered trademark which refers to an extensive product line of super alloys made from nickel, chromium and also austenite. Inconel alloys are usually utilized in high temperature applications. They are known for the outstanding resistance against corrosion and oxidation. They are frequently used in applications that run in harsh environments, especially those work in high temperature. When heated, this highly specialized alloy forms a thick and passivating oxide layer that protects its surface from extreme heat. Regardless of the temperature, Inconel can still retain its strength. This capability allows it to be used in high temperature applications where steel and aluminum cannot withstand. It is remarkable high temperature strength is due to precipitation strengthening or solid solution strengthening. In precipitation hardening and age hardening, nickel and niobium are combined to form Ni2Nb or gamma prime, an intermetallic compound. Gamma prime is responsible for forming small crystals that prevent the alloy from slipping at high temperatures. 718Inconel is difficult to shape because of rapid work hardening. After it underwent the first machining process, work hardening plastically deforms either the tool or work piece on the next processes. As a result, age-hardened Inconel are machined with the use of hard tool.
Applications of Inconel:
Most of the machining may be performed after age-hardening and the external threads are machined by using a screw machine to roll the threads. Due to the micro structural segregation and cracking of alloying components in the heat affected area, welding 718 Inconel alloys is not an easy task. However, some alloys have been purposely designed to address this problem. The most common welding technique used is gas tungsten arc welding. Moreover, new methods such as the pulsed micro laser welding were used to join alloys. Inconel alloys are widely used in applications that work in high temperature environment. They are primarily used in gas seals, turbine blades and combustors as well as turbocharger seals and rotors, high temperature fasteners, motor shafts, pressure and chemical processing vessels steam generators heat exchanger tubing and exhaust systems. These alloys are also used in boilers found in waste incinerators.