Authors: A Madariaga J A Esnaola E Fernandez P J Arrazola A Garay F Morel
Publish Date: 2014/01/12
Volume: 71, Issue: 9-12, Pages: 1587-1598
Abstract
Surface integrity SI and particularly the residual stress profile has a great influence on the fatigue life of machined aeronautical critical parts Among the different cutting parameters that affect the final SI tool geometry is one of the most important factors In particular tool nose radius determines the surface roughness as well as the thermoplastic deformation of the workpiece Indeed the use of large tool nose radius in the industry enables 1 increasing the feed rate while keeping the roughness values below specifications and 2 reducing the influence of the tool wear in the surface roughness Therefore in this study the influence of tool nose radius in the induced residual stress profile and workhardened layer when face turning Inconel 718 is analysed for a cutting speed range between 30–70 m/min and a feed rate range of 015–025 mm/rev For this purpose residual stress profiles and workhardened layer were measured by xray diffraction method after machining with a 4 mm nose radius Then results have been compared against different tool nose radius studies carried out by other authors for the specified working conditions Results revealed that residual stress profiles varied when machining with different nose radius for the studied range In particular the increase of the nose radius brought to a higher difference between surface tensile stress and subsurface compressive peak stress which is attributed to an increase of the thermal effect Moreover thicker workhardened layer around 100 μm was observed when machining with largenose radius for the studied working conditions
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