Comparison of Cold and Hot Forged EN8 Flats: Spring Back Effect, Surface Hardness and Microstructural Features

摘要

This paper reports the comparison of cold and hot forged EN8 flats for spring back effect, surface hardness and microstructural features as a case study of an industrial component 'U-Fork' (a subpart of tractor's three-point hitch's lift rod). The industrial component/benchmark has been selected as a common agricultural automobile component used under cyclic loading conditions. For this comparative study, surface hardness and surface roughness (Ra) of the material have been analyzed by using micro-Vickers hardness and 3D rendered images, Ra profiles, amplitude distribution function, respectively, whereas microstructure and its features (grain size number, average grain diameter, porosity, etc.) have been characterized using energy-dispersive X-ray spectroscopy and scanning electron microscope. The result of the case study reveals that hot forging has increased the dimensional accuracy by 11.15%, overcoming the spring back effect. Also, a significant reduction in porosity (54.28%) and increment in surface hardness (15.66%) are observed for hot forged EN8 flats in comparison to cold forged components.