Examining the machinability of 38MnVS6 microalloyed steel, cooled in different mediums after hot forging with the coated carbide and ceramic tool

Abstract

In this study, the effect of the microstructure, hardness, and cutting speed on main cutting force and surface roughness in medium carbon microalloyed steel cooled in different mediums after hot forging, was investigated. As-received sample, which was not hot forged, and the samples cooled in the sand, air, oil, and polymerized water after hot forging were used for the experimental studies. The machinability tests were performed via turning method by using coated carbide and coated ceramic cutting tools with five cutting speed (120, 150, 180, 210, and 240 m/min), constant feed rate (0.04 mm/rev), and constant depth of cut (0.6 mm). The microstructure examinations of the samples were carried out and their hardness values were determined. Also, the wear of cutting tools were examined with scanning electron microscope. In the experimental study, it was revealed that the microstructure, hardness and cutting speed had a significant effect on the surface roughness values of the samples cooled in dissimilar environments following forging. Moreover, the samples cooled in air and polymerized water, whose hardness increased depending on the increase in the cooling rate, had the highest cutting force after machining by using the coated carbide and ceramic tool.

An investigation on machinability of AISI D2 steel during hard milling with multi-resolution analysis of vibration

“…It is noticeable in this figure that surface roughness reduces rapidly as the cutting velocity is increased from 100 to 140 m min −1 , and then gradually as the cutting velocity is increased further. This result is in agreement with the findings of Özlü et al [25]. The reason behind the reduction of surface roughness with rising cutting speed may be the thermal softening of the workpiece material caused due to the elevated temperature at higher cutting speeds.…”

Evaluation of the mechanical properties and machinability of chromium and molybdenum-added powder metallurgy steels

“…24,28 Another reason for the decline in strength included the formation of coarse precipitates, which had weak effects on preventing the movement of dislocations. 29 For example, Özdemirler et al reported that the average grain size increased slightly with the increase of NbC ratio from 0.2% to 2% by weight. The excessive formation of large NbC precipitates at the grain boundaries, the inability of the carbonitrides formed to reduce the grain size sufficiently, and the precipitate density formed at the grain boundaries making the grain boundaries more brittle was reported as the reason as this situation.…”

Invar 36 Alaşımının Seramik Takımlar ile İşlenmesinde Kesme Kuvveti Bileşenleri ve Yüzey Pürüzlülüğü Bakımından İşlenebilirliğinin Değerlendirilmesi

“…Diğer yandan, kesme hızındaki artışa bağlı olarak Fc'nin 180 m/dak Vc'e kadar azaldığı ve bu seviye geçildiğinde düzensizleştiği görülmektedir. Literatürde, metal kesme işlemlerinde kesme hızındaki artışa bağlı olarak genellikle kesme kuvvetinin azaldığı bildirilmiştir [27][28][29][30]. Bu durum, kesme hızındaki artış ile deformasyon bölgesinde oluşan sıcaklığın artmasıyla, takım-talaş temas yüzeyinde yapışan malzemenin kayma dayanımının azalması ile açıklanabilir [31].…”