Investigation of Materials to Resist Hot Corrosion in Small Gas Turbine Engine Recuperators

摘要

Theoretical and experimental investigations were made of hot corrosion in Type 347 stainless steel and three other candidate materials. The preliminary brazing tests, now complete except for microprobe analysis, consisted of metallographical evaluation of the brazed joints and a 100-hr static hot corrosion test at 1500F. The materials selected for further testing are Hastelloy X, Incoloy 800, Multimet N-155 and CRES 347. The stress rupture hot-corrosion test, in progress, consists of exposing pressurized tubes to a synthetic environment similar to the composition of a gas turbine engine exhaust at three temperature levels to represent the spectrum of recuperator operating conditions. Time to rupture in hours covering failures to date are presented as well as a preliminary failure analysis. The plotted results indicate that all but CRES 347 would be suitable as a recuperator material operating in a 1300 to 1500F temperature. (Author)