Development of a Die Material for Isothermal Forging of Superalloys in Air
スポンサーリンク
概要
- 論文の詳細を見る
In isothermal forging, since the die is heated as well as the workpiece, high-temperature strength is essentially required for the die material. In particular, isothermal forging of superalloys is carried out at high temperature ranging 1000-1100°C, thus a molybdenum-base alloy, TZM, is generally used as a die material. Although TZM has good high-temperature strength, its oxidation resistance is very poor at above 600°C, therefore, forging must be done in vacuum or inert-gas atmosphere.If there is a die material having both enough strength and oxidation resistance at around 1000-1100°C, isothermal forging of superalloys in air will be possible, and the forging apparatus will be simpler.To develop such a die material, the authors directed their attention to chromium free nickel-base cast alloys, because such alloys are able to contain a large amount of heavy metals such as molybdenum and tungsten, as being soluble in γ and γ' instead of chromium, and are expected to have higher strength at above 1000°C.Several conventional and experimental alloys were investigated. From the results of compression, compressive creep and oxidation resistance tests, "Nimowal" (Ni-10Mo-12W-6Al-0.01Y) showed the best properties as a whole. Its short-time strength is equivalent to that of Mar-M200 at 950-1000°C, higher than that of Mar-M200 and equivalent to that of TZM at 1050-1100°C. Its compressive creep strength is higher than that of Mar-M200 at 1000-1100°C. Oxidation resistance of Nimowal is equivalent to that of Mar-M200 and enough to be used in air. Moreover, JVimowal has better machinability than Mar-M200.Simulation tests of isothermal forging of superalloys in air were made with Nimowal being used as the die material. One-tenth model disk of In-100 was successfully forged from the extruded billet without any damage or significant oxidation of the die.
- The Iron and Steel Institute of Japanの論文
The Iron and Steel Institute of Japan | 論文
- The Evolution of Precipitates in Nb-Ti Microalloyed Steels during Solidification and Post-solidification Cooling
- Short Contribution to the Study of the Washing Effect in Electromagnetic Stirrers for Continuous Casting
- Nitrogen Bearing Martensitic Stainless Steels : Microstructure and Properties
- A Two-dimensional Finite Element Thermomechanical Approach to a Global Stress-Strain Analysis of Steel Continuous Casting
- Transformation Behavior and Microstructures in Ultra-low Carbon Steels