Kajian Permukaan Hasil Pemesinan dari Bahan Baja Paduan Kelas Tinggi Aisi 4337 Dibubut pada Lingkungan Pemesinan Hijau

Abstract

The objectives of research reported in this thesis are to determine the cutting condition which has a good possibility to realize the green machining ( dry machining) concept for high grade steel alloy, studying surface topography (surface roughness, lay, waviness, and defects), surface metallurgy (sub"'surface alteration) and mathematical model for surface roughness (Ra) which subjected to cutting condition. There were 9 (nine) samples made of high grade steel alloy AISI 4337 resulted under green machining operation and cutting speed (V) of 200 m/min, 250 m/min, 300 m/min; feeding (f) of 0.15 mm/rev, 0.2 mm/rev, 0.25 mm/rev; and depth of cut (a) of 1 mm, 1.5 mm, 2 mm. Under those cutting conditions, the variations of samples were also determined by tool flank wear with VB of0.1 mm, 0.3 mm and 0.6 mm. For the purpose of studying surface topography, the scanning electron microscope was used while optical microscope and microhardness tester were for surface metallurgy. Data resulted from the experiment was then compiled and analyzed by using Taguchi method Lg (34 ). The results of machining experiment show that the average surface roughness (Raavg) obtained at optimum cutting condition when VB of 0.1 mm, 0.3 mm and 0.6 mm are 1.467 micron, 2.133 micron and 2.8 micron, respectively. Those results were obtained under green machining environment and while those were carried out under wet machining, the results recorded are 1.833 micron, 2.667 micron, and 3.0 micron, respectively. In the case of surface metallurgy, the average microhardness under green machining in Vickers unit (HVavg) are recorded 260.0896, 298.0662, and 282.5247 when VB 0.1 tm:n, 0.3 Illlll, and 0.6 mm, respectively. Under wet machining, the results recorded are 257 .9939, 259.1587, and 260.4706, respectively. By using the multi linear regression, the mathematical models for surface roughness and sub~surface alteration (microhardness) can be derived in function of roughness or microhardness and flank wear. Moreover, it's obtained that the optimum cutting condition is the cutting condition which resulting surface roughness of 2.8 micron. From the results obtained in this study, it can be concluded that green machining produces better quality of machined surface comparing to wet machining and it is also proved statistically by F ~ test. Therefore, green machining is an option with good possibility can be implemented for manufacturing industry.