Advanced Materials Research Vols. 622-623

Abstract: This work presents the influence of workpiece preheat temperatures on the machinability of Ti-6Al-4V alloy and chip formation. Machinability has been studied in terms of cutting forces, surface roughness and tool wear. Influence of preheat temperatures on chip morphology and roughness of chip back surface has been studied using scanning electron microscope and atomic force microscope respectively to get better insight of tribology at tool-chip interface. Based on overall observations, preheat temperature of 300 0C was found as the most appropriate parameter.

Abstract: Machining of Ti25Nb3Mo3Zr2Sn beta titanium alloy is carried out under two different heat treatments, solution treated, and solution treated and aged conditions. The chips formed after machining were cold mounted, polished and etched to reveal their microstructures. Different chip parameters such as average chip thickness, shear angle, undeformed chip length, and distance between serrations were measured and reported for both the heat treated samples for a wide range of cutting speeds, ranging from 5 m/min to 175 m/min. The results obtained were explained in terms of the heat treatment (hardness) of the samples and the cutting speeds.

Abstract: The article deals with the influence of the laser melting process on the surface roughness characteristics of the coat deposited on material by electrospark way granted by KEGA 035TUKE-4/2011 project of Ministry of education of Slovak republic. The aim of the article is research of material properties after coating by WC-Co and laser treatment. As the research method were used experiments and tools of statistics. Experiments were carried out on WC-Co coat (the anode), which was deposited on C45 carbon steel (the cathode) and molten by a laser beam. After surface treatment were analysed of changes in surface structure of the coat. Results of the research shows influence of parameters of this process to roughness, tribologic properties and morphology of the surface layer prepared by WC-Co coating and laser treatment.

Abstract: Aluminum alloys offer number of various interesting mechanical and thermal properties which classified them among most commonly used lightweight metallic materials. Generally machining of aluminum alloys inherently generates high chip sticking on tool face and changes the tool edge geometry, which not only reduces tool life but also impairs the product surface quality. This study investigated tool wear mechanism, surface integrity, and tool life in different cutting conditions to achieve finest surface roughness with considering longest tool life. Turning experiments performed under dry orthogonal cutting of Al6061 using carbide CVD tri-phase coated inserts. Constant depth of cut with different cutting speeds and feed rates utilized in experiments. Insert’s rake and flank faces investigated to figure out wear mechanisms. In addition scanning electron microscope (SEM) employed to evaluate various wear types. Surface integrity and effect of built up edge in surface roughness deviations studied in each cutting condition. Additionally, results of experiments demonstrated that built up edge covered tool cutting edge and increased tool life by decreasing pace of the abrasive wear propagation on the flank face with sacrificing surface roughness. All in all the main reason for flank wear was abrasive and adhesion of aluminum on tool faces.

Abstract: In automobile and aeronautical industries, complex moulds and dies is produced by Electrical Discharge Machining process. The surface finish is determined by the crater volume in EDM process. The amount of crater volume is influenced by the amount and distribution of discharge energy. The discharge energy is directly proportional to the average discharge current. This amount of current is determined by the duration of discharging effect. This study deals about evaluating the performance of iso current pulse generator on machining characteristics in EDM. Due to its ability of reducing stochastic nature in EDM process, iso pulse generator could produce better surface finish than conventional transistor pulse train generator with higher material removal rate.

Abstract: The objective of the research was to analyze the influence of initial roughness on the wear rate of component samples made of bearing steels. AISI 52100 samples were prepared with three different roughness values by varying the depth of cut and feed rate in milling process. Dry reciprocating wear tests were performed under the same laboratory conditions and at different loads and sliding speeds. A fractional factorial approach with one-third of 33 experimental design without replication was followed here. The overall wear rate was found out by mass loss method. The results were analyzed using contour plots between the factors influencing the wear rate as well as mean coefficient of friction. The results indicated that the wear rate and coefficient of friction was influenced by load, roughness and their interaction.

Abstract: The Ti-6Al-4V titanium alloy is commonly used in aerospace, automotive industries and for manufacturing of medical implants, due to its biocompatibility. The objective of this work is to investigate the performance of precision turning using conventional lathe on Ti6Al4V under dry working conditions. A range of parameters that involve the machining processes were recognized and a consensus was reached to finalize its values. The proposed work is to carry out machining under the selected levels of parameters to evaluate the cutting force and surface roughness generated as the consequence of the machining process. Cutting speed, feed rate, depth of cut and nose radiuses are considered as the machining parameters for experimentation. The variation in the surface roughness and the cutting force for the variation of each machining parameters are presented graphically.

Abstract: A Stiff Air Layer, Formed around a Rotating Grinding Wheel, Tends to Restrict Grinding Fluid Penetrate Deep inside the Grinding Zone. for this, much Fluid Is Wasted, and Thermal Defects in Grinding May Not Be Controlled. in the Present Experimental Work, a Flood Cooling System with Pneumatic Barrier Is Used for Delivering Grinding Fluid. the Pneumatic Barrier Breaks the Stiff Air Layer, and Therefore, Grinding Fluid Reaches Grinding Zone. an Exotic Nickel Base Alloy, Inconel 600, Is Taken for Surface Grinding Experiments Using an Infeed of 30 µm under Different Environmental Conditions. the Effect of Different Experimental Conditions Is Investigated in Respect of Grinding Force, Chip Formation, Surface Quality and Wheel Condition. the Experimental Result Shows that Grinding Forces and Wheel Wear Are Remarkably Reduced, and Favourable Chips and Good Surface Quality Are Obtained with the Use of Flood Cooling along with Pneumatic Barrier Setup Compared to other Environmental Conditions.

Abstract: The quality of a machined surface is becoming more and more important to satisfy the increasing demands of sophisticated component performance, longevity, and reliability. The objective of this paper is to analyze the performance of precision turning using conventional lathe on Ti6Al4V under dry working conditions. Various parameters that affect the machining processes were identified and a consensus was reached regarding its values. The proposed work is to perform machining under the selected levels of conditions and parameters and to estimate the, cutting temperature and surface roughness generated as the result of the machining process. ANOVA is used to find the percentage contribution of each parameter to the surface roughness and cutting temperature.

Abstract: This research work presents the results of an experimental investigation on wear study of cermet cutting tools during machining of AISI 4340 steel (45 HRC). The cryogenic treatment and Ti-Al-N coating were performed over cermet inserts substrate. The four different cermet inserts such as cryogenically treated (Tool 2), cryogenically treated and subsequently Ti-Al-N coated (Tool 4), Ti-Al-N coated (Tool 3) and plain cermet (Tool 1) were taken. Experiments were performed to evaluate the tool wear at different machining conditions. Result indicated that cryogenically treated and subsequently Ti-Al-N coated cermet cutting tool performs better than other cermet cutting tools.