Investigation of Surface Roughness in Machining of Aisi 1040 Steel

Investigation of Surface Roughness in Machining of Aisi 1040 Steel
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  Proceedings of the 2 nd  International Conference on Current Trends in Engineering and Management ICCTEM -2014 17 – 19, July 2014, Mysore, Karnataka, India   36   INVESTIGATION OF SURFACE ROUGHNESS IN MACHINING OF AISI 1040 STEEL Akshaya T Poojary 1 , Rajesh Nayak 2   1 (B. Tech Student, Mechanical Engg, Manipal University, India)  2 (Assistant Professor, Mechanical Engg, Manipal University, India)   ABSTRACT This paper presents the optimized method of machining process for improved surface finish of AISI 1040 steel which was turned under dry, wet (SAE 90 soluble oil) and cryogenic (dip in LN2) condition. The surface roughness was measured using Surtronic 3+.The values of surface roughness for each of the machining process were plotted with variant feed rate. Cryogenic machining showed remarkable reduction in surface roughness compared to both dry and wet machining especially at high feed rates. The percentage reduction in surface roughness observed in cryogenic machining compared to wet machining was 7.54%-19.52%. Keywords: AISI 1040 Steel, Cryogenic (dip in LN2), Dry, Surface Roughness, Wet. 1.   INTRODUCTION Steel has wide applications in industries and also the demand of steel is increasing day by day. The only way to meet the increasing demand of consumers is to increase the rate of production and processing. This urge to meet high rate of production causes generation of high temperature zone at the tip of the tool (tool wear) and also detoriates the quality (surface finish, dimensional accuracy) of product manufactured. But no compromise can be allowed with surface finish and dimensional accuracy of the product and at the same time the life of the cutting tool has to be taken care too. In order to overcome these problems during machining either coated cutting tools or appropriate cutting fluids are used. [1]There are varieties of soluble oil, mineral or vegetable oil base and mineral oil used to reduce the tool tip temperature and increase the quality of the product. These oils perform two significant tasks of cooling and lubricating. Some of these oils are used as emulsions and some as neat oils. In general oil-and-water emulsions have large heat absorbing capacity than neat oils hence they are more often used where cooling is required. They are used in machine tools with varying percentage of water and oil. Neat oils are used where lubrication plays a vital role such as gear cutting, thread cutting etc. [2]But these conventional coolants fail to provide desirable control over cutting temperature in the cutting zone and it also creates some techno-environmental problems. [3]The use of conventional coolants not only restricts itself with these problems but also effects workpiece and the parts of the machine tool by causing corrosion which ends up in the failure of the part. In recent years of investigations performed on machining, use of cryogenic liquid as coolant was found. Cryogenic cooling involved a liquid coolant whose boiling point is at subzero temperature. This coolant acting as sink would absorb the heat from the tool tip temperature which forms the source of heat generation. This is based completely on the principle of flow of heat from higher temperature to lower temperature. There are experiments conducted on steel using carbon dioxide as the cryogenic coolant. Even though CO 2  is cheaper and available in abundant it has two major disadvantages such as affecting the respiratory system of the operator whose is in contact with it for prolonged period of time during machining   INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING AND TECHNOLOGY (IJMET) ISSN 0976 – 6340 (Print) ISSN 0976 – 6359 (Online) Volume 5, Issue 9, September (2014), pp. 36-43 © IAEME: Journal Impact Factor (2014): 7.5377 (Calculated by GISI)   IJMET   © I A E M E    Proceedings of the 2 nd  International Conference on Current Trends in Engineering and Management ICCTEM -2014 17 – 19, July 2014, Mysore, Karnataka, India   37   and it also has adverse impact on the greenhouse effect as CO 2  is a greenhouse gas. Due to this major disadvantage Liquid Nitrogen(LN 2 ) is much preferred compared to carbon dioxide(CO 2 ) when it comes to cryogenic cooling.[4,5,6] Cryogenic cooling provided less cutting forces, reduced cutting temperature, better surface finish and improved tool life compared to dry machining. The physical properties of LN 2  are:- Boiling Point : -195.8°c Liquid Density : 808.607 kg/m 3  (1.013 bar at boiling point) Among the variety of steel grades available AISI 1040 steel is widely used in industries for manufacturing of crankshaft, fasteners, coupling and cold headed parts.Thus the current work experimentally shows the comparison and analysis of surface roughness for turning of AISI 1040 steel at various feed,speed and depth of cut using High speed steel single point cutting tool for dry machining,machining using conventional cutting fluid(SAE 90 Soluble oil) and cryogenic cooling(dip in LN 2 ). 2.   LITERATURE REVIEW There has been a lot of research work conducted on machining (turning, grinding) of mild steel. [7]In dry machining of a metal in lathe, oxygen jets were directed at tool-chip interface to perform the work of a coolant. It was found that oxygen was particularly effective in reducing cutting forces and improving surface finish.[8]In an experimental study conducted on metal cutting under high hydrostatic pressure, a hydrostatic pressure of 0MPa-150MPa was applied using a pressure vessel. The orthogonal cutting process was carried out using hydraulic oil ISO VG 32 as hydraulic fluid. It was concluded that hydrostatic pressure was successful in penetrating hydraulic oil into chip-tool interface and at tool workpiece interface and thereby improving the surface finish with the increase in hydrostatic pressure for both aluminium and steel workpieces. [9]In an comparative study experiment conducted on 1045 cold rolledsteel for dry machining, flood cooling using water based cutting fluid and micropool lubrication using cutting oil and solid lubricant, it was observed that micropool lubrication supplies minimum amount of lubricant to the chip-tool interface resulting in improving the metal to metal contact conditions by reducing the coefficient of friction.[10]In an investigational study of applicability of solid lubricant in turning of AISI 1040 steel a new setup was designed for the application of fine solid lubricant powder(2µm average size particle) at tool and work interface. The solid lubricant powder used for machining was molybdenum disulphide. It was found that this method of solid lubricant machining was successful in reducing the surface roughness and chip thickness ratio. It also improved the surface finish by 5% to 30%. [11]In turning of C45 steel under compressed air, oil water emulsion, water vapour as coolant and lubricant and dry cutting, it was found that the use of water vapour as coolant and lubricant reduced the values of various significant parameters such as cutting force, friction coefficient, chip deformation coefficient and further it reduced the values of surface roughness thus improving the surface finish. [12]In a turning operation performed on ANSI 1045 steel material using cemented carbide tool P10 under variety of coolants such as oil water emulsions,CO 2 ,O 2 ,water vapour, WV&C (mixture of water vapour and carbon dioxide gas),WV&O (mixture of water vapour and oxygen gas) and machining under dry conditions it was observed that water vapour, gases andmixture of water vapour and gas as a coolant and lubricant emerged out to give better results than the remaining machining conditions.[13]In comparison of applications of gases, wet and dry turning of AISI 1040 steel oxygen, nitrogen and carbon dioxide gases were used at constant cuttingspeed with three different levels of feeds and depth of cut. The cutting tools used for turning operation were P20 grade TPUN160312 type uncoated inserts and the tool holder used was CTGPR2020. Results revealedthat finer surface finish was obtained at high feed rates with the application of gases. [14] A new method of lubrication was proposed, which uses supercritical carbon dioxide (scCO 2 ) along with straight soyabean oil. The soyabean oil-in-scCO 2 is sprayed during tapping operation and it was observed that CO 2 due to its rapid expansion cools the cutting zone and the combination of both high pressure and low surface tension are primarily responsible for supplying the straight soyabean oil at interstitial spaces between the tool-wokpiece interface thus providing better desired results than only straight petroleum mineral oil and petroleum oil. [15] During turning of AISI 1045 steel under cryogenic condition(cryogenic coolant CO 2 ),wet machining and under dry machining it was concluded that application of CO 2  gas improved the surface finish by 5%-25% compared to wet machining.[16]In plain turning of stainless steel work under dry and cryogenic conditions it was concluded that cryogenic cooling is more beneficial for higher machining rate with better quality but the consumption of liquid nitrogen was high which lead to increase in overall cost of machining.[17] An experiment was conducted on turning of AISI 4037 steel under dry, soluble oil and cryogenic condition by spraying the jet of liquid nitrogen at tool tip. The experiment was conducted at industrial feed-speed combination using a coated carbide insert. It was also concluded that application cryogenic cooling resulted in better surface finish and higher dimensional accuracy compared to dry and wet machining.[2] An experimental investigation was performed on turning of AISI 1045 steel and aluminium 6061-T6 alloy using multi coated carbide and uncoated carbide cutting tools respectively. The jet of liquid nitrogen was sprayed at the rake face of the tool (Rake cooling).The application of LN 2  jet reduced the chip thickness ratio by 25% compared to dry machining and the shear angle in cryogenic machining was increased up to 30%.  Proceedings of the 2 nd  International Conference on Current Trends in Engineering and Management ICCTEM -2014 17 – 19, July 2014, Mysore, Karnataka, India   38   [4] A cryogenic cooling experiment on plain turning of AISI 1060 steel was performed by spraying liquidnitrogen jet. The experiment was conducted at industrial speed-feed combination by using two different carbide inserts of different geometric configurations. Cryogenic cooling reduced tool wear, improved tool life and surface finish compared to dry machining.[18]N. R. Dhar et al. machined(turning) AISI 4140 steel under cryogenic cooling and compared the values of various parameters with dry cutting. The different cutting tool inserts used for this operation were SNMG 120408-26 and SNMM 120408.Improved surface finish and dimensional accuracy were obtained by adopting the method of cryogenic cooling. [19] A variety of methods used to machine difficult to cut materialsusing cooling and lubrication such as minimum quantity lubrication (MQL), high pressure coolant (HPC), compressed air cooling, solid lubricants/coolants and cryogenic cooling using carbide inserts were performed. Cryogenic cooling showed better results at high feed rates thus it was concluded that this method had the potentialof increasing the productivity. 3.   EXPERIMENTAL SETUP The turning operation was performed on medium carbon steel AISI 1040 in PSG A141 lathe (2.2 KW) using High Speed Steel (HSS) single point cutting tool under dry cutting, conventional cutting fluid and cryogenic cooling conditions. The workpiece of 24mm diameter and 304.8mm length was used to conduct the experiment. The chemical composition of AISI 1040 Steel is as shown in Table 1. Table 1: Chemical Composition of the workpiece material AISI 1040 steel, by weight [20] The values for 3 different cutting speed, feed and depth of cut are as shown in Table 2: Table 2: Experimental Conditions Figure.1: cryogenic machining The workpiece used for each of the machining conditions (dry, wet and cryogenic) were separate but were taken from the same parent material so as to avoid any deviation in the results obtained due to variation in chemical composition. The workpiece was dipped in cryogenic liquid (LN2) for a specified period of time and then fixed on to the chuck for turning. TheFig.1 showsturning of AISI 1040 steel which was dipped in cryogenic liquid (LN2). Material C Mn P S AISI 1040 Steel 0.37-0.44 0.60-0.90 0.040 0.050 Work specimen  AISI 1040 steel (Ø24mm and 304.8mm long) Cutting tool  Single point high speed steel cutting tool Process Parameters Feed 0.1mm/rev,0.13mm/rev and 0.18mm/rev Depth of Cut 0.25mm,0.5mm and 0.75mm Cutting Speed 27.14m/min, 33.92m/min and 43.73m/min Machining Environment  Dry, Wet and Cryogenic conditions  Proceedings of the 2 nd  International Co The surface roughness of the instrument Surtronic 3+ (112/1590).The le range of 10µm, 100µm and 500µm.Reso selectable cut off value of 0.25mm, 0.8mm measure the surface roughness. The softw Profile 3.1.TheFig.2 shows the photographi  Figur 4.   RESULTS Surface roughness (Ra) plays a si respective machining condition. The undes with another mating part which together fo method to obtain surface finish must be s cutting forces and specific cutting ener workpiece.[22,10]Studies of Brinksmeieret roughness compared to that of 4% emuls depends upon various parameters such as t it and the combination of feed, speed and d This experiment conducted on mi cutting speed, feed and depth of cut was c analysis them and to conclude the optimiz finish. All the graphs below show the vari AISI 1040 steel under dry, wet (SAE 90 sol amount of reduction noticed in surface rou further reduced compared to wet machining Figure. 3: surface roughness vs. f ference on Current Trends in Engineering and Manage 17 – 19, July 2014, Myso 39   achined workpieces were measured using Taylor H ngth for which roughness test was carried out was 4m ution used to carry out the experiment was 0.5µm.T and 2.50mm.Skid pick up stylus with diamond tip radius are used for data acquisition and evaluation of surface view of surface roughness measurement conducted. . 2: photographic view of surtronic 3+ gnificant parameter in deciding the level of surface fini irable surface finish of the machined part will not allo rms a component. In order to avoid the occurrence of su lected and put to practice. [21, 10]Earlier studies revea y would certainly lead to improvement of the sur al. concluded that graphite assisted machining results in ion and dry machining conditions. The quality of sur e machining conditions, material composition of work, t pth of cut considered for machining. ld steel specimen on three different machining conditio nducted to obtain the surface roughness in each of the d method of machining condition for arriving to the hig tion of surface roughness with respect to feed obtained uble oil) and cryogenic cooling condition. For Fig.3 ther hness obtained due to wet machining compared to dry a with the use of cryogenic liquid in cryogenic machining.  ed for cutting speed = 27.14m/min and depth of cut =   ent ICCTEM -2014 re, Karnataka, India   bson manufactured .It had a selectable e instrument had a of 5µm was used to roughness was Taly sh obtained with the it to be assembled ch problems the best led that reduction in face quality of the reduction in surface face finish obtained ool and coating over ns and at 3 different achining process to hest possible surface during machining of e was an appreciable d surface roughness 0.25mm/rev

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Jul 23, 2017
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