STRUCTURE AND PROPERTIES OF THE KhN60MVTYu (EP487) ALLOY

Abstract : The structure and properties of the new KhN60MTYu (EP487) heat-resistant, wrought nickel alloy (17-20 percent chromium, 9-11 percent molybdenum, 4-5 percent tungsten, 2.2-2.8 percent titanium, 1.0-1.5 percent aluminum, not more than 6 percent iron and 0.08 percent carbon) has been investigated. The alloy was developed by TsNIIChM jointly with other institutions and is being used for the manufacture of welded articles operating at 750-900 degrees centigrade. The alloy attains its maximum strength after aging at 800-850 degrees centigrade. Its hardness increases rapidly during the first 2-3 hours and then increases insignificantly with holding time increasing up to 25 hours. The microstructure of the alloy, after aging at 800 degrees centigrade for 10 hours, consists of a solid solution with precipitates of the strengthening Gamma-phase at grain boundaries and fairly large inclusions of carbide phases. The optimal mechanical properties of the alloy are obtained after air-quenching from 1100-1130 degrees centigrade and aging at 850 degrees centigrade for 3 hours. (Author)