“NC “Rosneft” – Research-and-Technical Centre”
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INFLUENCE OF REFRACTORY FILLERS ON THE PROCESS OF COMPOSITE BRAZING OF DIAMOND-ABRASIVE TOOLS
Description
Brazes with increased viscosity are needed for brazing of abrasive diamond tools with working surface of complex contoured shape. It’s known that high viscosity is a property of composite brazes consisting of fusible matrix and refractory filler that is not melting during brazing. Goal of the work is to research the influence of refractory fillers on the process of composite brazing of diamond-abrasive tools and on that basis discover the optimal composition of braze. Composite brazes Sn-Cu-Co were researched in the work. It is determined that at least 26-28% (by mass) of cobalt powder should be included in brazes for giving the braze Sn-Cu-Co necessary viscosity and for creation of uniform diamond-comprising layers with thickness up to 2.5 mm on the vertical layers and sharp edges of tools. It is determined that solid-state sintering of powders on the initial stage of heating the composite braze leads to emerging of internal stresses and forming cracks. Inert additions that prevent solid-state sintering should be include in braze to prevent cracking. Optimal inert addition for brazes Sn-Cu-Co is the tungsten powder. Minimum content of tungsten needed to prevent cracking is 6% (by mass). Optimal content of components in composition braze for brazing shaped diamond-abrasive tools is (% by mass): 30 Co, 20 Sn, 43 Cu, 7 W
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