'DEVELOPMENT OF NI-CU-SI 'VKM' GRADE CAST ALLOY FOR AIRCRAFT COMPONENTS'

摘要

The new alloy VKM, which is a Nickei-Copper-Silicon, cast grade, is now developed indigenously and components manufactu red from this alloy are used in sliding valves of fuel equipments and also applicable to be used as friction parts. HAL, Koraput Foundry has taken up the task to indigenously develop this alloy and manufacture the castings from virgin material through inve stment casting processes. Further the casting process parameters have been stabilized through certain characterization test requirements suc h as, inclusion check, grain size, cell size measurements, microstructure after heat treatment, tensile properties at room temperature as well as at 100 �C. Shell preparation was done by using the binder hydrolyzed ethyl silicate and filler material as Disthene Siliminite. Stuccoing was carried out by using different grade of electro corrundum sand. Finally dewaxing, prefiring and calcination process were carried out before pouring. The alloy was prepared by vacuum induction melting process in an induction furnace. Chemical composition test was analysed by using optical emission spectroscopy. Further the cast bars were h eat treated and different metallurgical characterization and mechanical properties were examined. Castings manufactured from this developed alloy have sufficient strength and superior surface finish (due to vacuum induction melt.) to be used for the pump a ccessories, where frictional forces play a major role.