“An Experimental Approach for Eliminating C...

“An Experimental Approach for Eliminating Crack Formation on Chisel Due to Thermal Stress in TI Carbide and Steel Brazing Process”

Author Name : Faisal Khan, Dr. Yogesh Agrawal, Dr. Vidosh Mahate, Dr. Vikas S. Pagey

ABSTRACT

The basic aim of the experiments conducted was to a unified approach to eliminating crack formation due to thermal stress in tungsten carbide and steel brazing process. The thermal stress produced upto 85-90% because of the Effect of selection of filler material, brazing gap, cooling method, brazing paste, brazing standard procedure were studied experimentally. Earlier we make the TC chisel brazing on induction machine by using silver filler material with powder flux. TC chipped off, TC Cracking while chisel used for making the teeth of files & hence getting less tool life. That time we analysed the parameters which are cause to rejection. So we found some major reasons. Earlier we used Silver foil & Rupatam A flux in brazing. But some limitations observed after brazing i.e. oxide formation seen near brazing joint, high thermal stresses produced, tensile strength found at lower side, also having low working strength found.The based on the foregoing studies, the main aim of the ongoing experimental trail work is to eliminate crack formation in TC after brazing by using proper filler material with proper brazing gap between TC & steel (EN-24). Also increase working strength of TC chisel by controlling hardness of steel also by controlling brazing temp.In present study six test piece (Chisels) made up from different filler material and different affecting parameters. We analysed all six test pieces, on which we conclude, we use the Black flux paste with Nibro Foil. Keeping brazing gap between TC up to 0.4-0.6 mm. slow furnace cooling, brazing temperature up to (890-900ºC). It prevents oxide formation, and thermal stress measured 10-15% in chisel. tensile strength and working strength found satisfactory. From the experimentation we conclude that brazing process is validated and gives the accepted results within the optimum parameters range.

Keywords: Silver Filler Material, Powder Flux, Black Flux Paste, Thermal Stress