Ferritic-Based High Temperature Alloy
Ferritic-based high temperature alloy materials are widely used in various engineering applications due to their low cost, good machinability, ease of formability and good weldability. They are most often used in aerospace and automotive applications because of their good oxidation and corrosion resistance. High temperature alloys are extensively used for components exposed to operating temperatures above 530°C for applications such as furnace and boiler components, aircraft gas turbines and gas turbine blades and vanes.
Ferritic-based high temperature alloy materials have excellent strength, ductility and formability at temperatures above 500°C. They exhibit superior hot hardness and offer superior creep strength and creep rupture resistance at elevated temperatures. The alloying elements include chromium, molybdenum, tungsten, nickel and silicon, which helps to enhance the creep rupture strength. Chromium provides oxidation and corrosion resistance and also helps to increase the creep strength. Molybdenum imparts high temperature strength and reduces the temperature at which creep starts. Nickel imparts strength also at high temperature and helps to improve the resistance to sigma phase formation. Tungsten helps to improve the oxidation resistance of the alloy and also helps to increase the hot strength. Silicon improves the hot hardness of the material. The alloys can be used in parts operating at temperatures up to 1000°C.
Ferritic-based high temperature alloy materials also exhibit good weldability. The alloys can be readily welded using conventional techniques such as tungsten inert gas (TIG) and metal inert gas (MIG) welding. The welded joints are of good strength and ductility. The weldments can be easily machined and shaped which make the alloys suitable for various components used in aerospace and automotive applications.
The application of ferritic-based high temperature alloy materials has expanded due to their cost-effectiveness and wide availability. They have been used in many engineering applications including furnace walls, turbine blades, exhaust pipes and fuel injectors.
Due to their excellent mechanical properties and oxidation and corrosion resistance, ferritic-based high temperature alloy materials are a preferred choice for many aerospace and automotive components. These alloys offer several advantages over other high temperature alloys including ease of formability, weldability and machinability. They are also cost effective and widely available, making them an ideal choice for many engineering applications.
