Investigation of the machinablity at the mouldmetal interface in FNB casting

Abstract

quotIn foundries, it becomes necessary to minimize the machining allowance for economic reasons. It will save resources and costs by reducing the energy and expenses incurred on re-melting, machining and tooling. A deeper understanding of the complicated microstructures developed within about 3.5 mm of the mould-metal interface is necessary. The current research work uses a unique experimental design that involves performing surface and subsurface microscopy and spectroscopy at 0.5 mm intervals from the as-cast surface to a depth of up to 3.5 mm for three samples. The objective is on evaluating microstructure for determining graphite flake size, distribution, grouping, pearlite and ferrite percentage, and different elements including carbon, silicon, manganese, sulphur and phosphorous. All three samples were subjected to a hardness test, which is a measure of machinability. The relationship between hardness as a single response to percentage presence of elements, graphite distribution and pearlite has been established using statistical analysis. newlineAdditionally, the machinability is investigated in terms of tool life at different cutting speeds according to job and tool combination as per Taylor s tool life criterion and ISO: 3685 procedure for the electric motor body machining. At last, the specimen as per the AFS 5J test article is casted. It is machined for the identification of the machining forces using lathe tool dynamometer (LTD). The tool wear is measured using optical inverted microscope. On that basis, Taylor s tool life constants are identified. newlinequot newline newline