Machinability Studies on Carbon and Alloy Steels using Face Turning

Abstract

The present study is an experimental investigation on the machinability of carbon and alloy steels by face turning method. This study finds its usefulness in economic machining solution to fulfil the local objectives of knowing, in advance, the machinability of selected carbon and alloy steel material of grade: AISI-1050, AISI- 51100, AISI-52100, AISI-4320 and AISI-9320. The face turning method makes use of cylindrical steel bar specimen as test pieces for testing the machinability of the steels. The technical effectivity of the face turning method is assessed by studying: the cutting time required for the tool to reach flank wear upto 0.3mm (tool life criterion); tool wear development and wear mechanisms involved in machining; tool life studies and machinability indices of the work-material; surface roughness and microhardness investigations (SEM) of the machined surfaces; and chip morphology and crater wear studies. These aspects are further tested and verified for its repeatability and reproducibility. The tests are being carried according to some of the guidelines laid in the international standards, ISO 3685:1993(E) and American Foundry Society (AFS) standard machinability tests. The results presented here demonstrate the ability of the face turning method to assess the tool wear development while machining different work-materials; to evaluate the tool life for each of the work-material under consideration; to differentiate very distinctly and rank these materials according to their machinability; to investigate surface finish due to tool wear and micro-hardness of the machined surface generated after the tool wear reached its tool life criterion; to analyse the chip morphologies with crater wear; and to overall characterize the machinability of steels under consideration. The face turning method used here is simple and effective for the given tool-work material pair.