Effects of cutting fluids on the machining of hardened AISI 4320 steel

Abstract

Hard turning is a profItable alternative hl finish grinding in respect of dimensional accuracy and surface finish to fulfill functional requirement. improved perfonnance and prolonged service life llf the product. Hard turning is able to reduce processing time, production cost, ,urfacc roughness and ~elUptime appreciably in comparlson to grinding. But high heat generation at high production machining increase tool wear and deteriorates the job quality. The conventional cutting fluids are not that effeetlve in such situation. Minimum quantity lubrication (MQL) is a suitable alt~'l"natlvein thi. regard, In thi, research work, the effects of MQL on cutting perfonnance of hardened AISl4320 steel in respect of chip f<,nnalion, chip-tool interface lemperarure, tool "ear and produel quality have been ~tudicd using coated carbide insert (SNMG-TN 4000). Three types of culling fluids (soluble oil, vegetable oil and VO 68 cutting oil) have been used to compare the relative performance of th'l'>e culling fluids with each olher as well as with that of dry condition, Compared to dry condition, MQL performed better mainly due to substantial reduction in culling temperature that enabling favorable chip-tool int~'l"actlon.This also facj]jtated the substantial reduction in tmll "ear. dimensional inaccumcy and surface roughness. The result:>indicatcd that the u,e of minimum quantity lubrication (MQL) by VG 68 cutting oil pcrformed better in comparison to other cutting fluids in respect of chips formation mode. culling temperature, to"l wear, surface roughness and dimcnslonal devialion,