Abstract
In order to clarify the effect of die materials on the isothermal forging properties such as forging load, die filling and heat power consumption, forging tests of nickel-base superalloy Mod.IN-100 from a cylindrical preform to a disk shape with boss and rim have been performed. The die materials used are two refractory alloys, TZM and W–2ThO2, ceramic SIALON and nickel-base cast superalloy IN-100. Forging with refractory alloy dies are done in a chamber filled with inert gas (Ar) or vacuumized to prevent the oxidation of die. On the other hand, with ceramic or cast superalloy dies, forging can be done in air without the use of the chamber. In these tests, the HIP’ed and extruded preform from Mod.IN-100 powder is used as a test material, and a glass powder suspended in water is used as a lubricant. By using the optimum size preform, isothermal forging of Mod.IN-100 can be carried out successfully in all cases. There are no differences in load and material flow in forgings, regardless of the die material selected. From the practical point of view, however, the forging method with ceramic or cast superalloy dies in air has been experimentally proved to be more appropriate than that with refractory alloy dies in inert gas or vacuum.
