Characteristic of High Temperature Alloys and Name Various Alloys Gas Turbine

Characteristic of High Temperature Alloys and Name Various Alloys Gas Turbine Points : Characteristic of High Temperature Alloys and Name Various Alloys Gas Turbine, IN-738, U-500 , Cr-Mo-V, 12 Cr Alloys, M-152, A-286, G T D – III, IN-706 Name & Characteristics of Various Alloys Vacuum — cast nickel — base alloys strengthened through solution and precipitation — hardening heat treatments have been favored over the cobalt base alloys used because of the higher attainable strength. The Stress rupture strength of currently used nickel-base nozzle alloys (IN-38 and U-500) are compared to the currently used cobalt-base alloys: (FSX-4 14) this comparison is presented in the form of stress required-for-rupture as a function of a parameter relating time and temperature. IN-738 An alloy first developed by the international nickel co. to further enhance the corrosion life, coated blade have been introduced, resulting in a 50-100% extension of the corrosion life of IN-73. U-500 or nimonic. Both are the alloys the are precipitation hardened, nickel — base alloys. Their application to the last stage of higher-tiring temperature designs is a logical and conservative extension. Cr-Mo-V It is used in the quenched and temperature conditions to enhance bore toughness. 12 Cr Alloys This family of alloys has a combination of properties that make them especially valuable for turbine wheels. These properties include good ductility at high strength levels, uniform properties throughout thick sections, and favorable hot-strength at temperature up to 650°F. M-152 Alloys is a 2-3% nickel-containing member of the 12 Cr family of alloys, because of its outstanding fracture toughness in addition to properties common to other 12 Cr alloys. M-152 alloys is intermediate in rupture strength between Cr-Mo-V and A-286 alloys and has a higher tensile strength then either one. These features, together with its favorable coefficient of expansion and good fracture toughness, make this alloys attractive for greater use in gas turbine applications. A-286 A-286 is an austenitic iron-be alloys which has been used for years in aircraft engine applications and industrial gas turbine since 1 O65when technology advances made possible the used production of Sound ingots of sufficient 1965 when technology advances made possible the production of sound ingots of sufficient size to produce these wheels. Since that time A- 286 has been used in industrial disc and has had excellent service. G T D – III Alloy developed in 1973-1975, exhibits a stress rupture improvement over IN-738 equivalent to an increased temperature capacity of a approximate 40°F. The formulation concept of his alloy is unique in that it involves compositional balances of refractory containing elements (Mo, Ta, Cb) to prevent localized, accelerated, hot-corrosion, with increased firing temperature. IN-706 A recently completed development program involved the development of manufacturing process for large size IN-706 wheels, including full evaluation of the properties of this alloys. IN-706 is a nickel-base alloy with properties superior to A-286, and it is capable of being produced in larger sizes.