Sharma Rishi, International Journal of Advance Research, Ideas and Innovations in Technology © 2019, www.IJARIIT.com All Rights Reserved Page | 778 ISSN: 2454-132X Impact factor: 4.295 (Volume 5, Issue 2) Available online at: www.ijariit.com Effect of cutting conditions on surface roughness and cutting forces in hard turning of AISI 4340 steel Rishi Sharma sharmarishi5066@gmail.com Abhilashi Group of Institution, Mandi, Himachal Pradesh ABSTRACT In the present work, the comparison study for surface roughness and main cutting force is studded between Dry, Wet lubricant and solid lubricant condition during the turning the AISI 4340 steel, hardness 60 HRC with CBN insert. Water-based lubricant used as a wet lubricant and boric acid in powder form is used as a solid lubricant. The objective of this study is to know about optimum machining parameters and best conditions with dry or solid lubricants for hard turning operation and it is also important to find the research gap through different studies. The results indicated that there is a significant effect on surface roughness (Ra) and main cutting force (Fc) when cutting under different conditions (Dry, Wet and Solid condition) with different cutting parameters. It has been found that with solid lubricants surface roughness value decreased as compared to dry hard turning. The proper selection of lubricants in the solid state along with cutting conditions and tool angles is essential for achieving the overall improvement in the hard turning process. With the use of lubricants in the solid form, hard turning may become a viable alternative to dry and wet hard turning process. Keywords— Hard turning, Cutting conditions, Surface roughness, Response surface methodology 1. INTRODUCTION Hard turning is a process in which hard material which has a hardness above 45 HRC is machined with the help of single point geometrical tools [1]. To reduce the cost, improve quality and minimize setup times in order to remain competitive is a challenge to the manufacturer of those components and manufacturer of goods. Grinding is a process which is used in industries but it involves expensive machinery and lengthy setup times, high manufacturing time, costly equipment’s. In hard turning material removal rate is high that is why it is a fast process as compare to grinding hard turning process. The other advantages of precision hard turning over grinding include fewer production costs, high flexibility and enriched workpiece quality [2]. Hard turning is generally a replacement of grinding which is mostly used in automotive industries. As compared to the grinding process turning process for hard steel is preferred. The main factor takes towards the use of hard turning in place of grinding has been the development of various cubic boron nitride (CBN) cutting tool insert, PCBN, Ceramic insert, coated carbide, etc. which is capable of machining the high strength materials with a properly defined cutting edge. Ceramic tools are less hard then CBN tools in both low and high temperatures. High thermal conductivity and low thermal expansion coefficient are also important properties of CBN which are used in hardened steel turning. High CBN (around 90%), and lower CBN content (around 60%) are two different grades of CBN tools with a ceramic phase added to the material, usually titanium nitride. High CBN content tools are generally recommended for the turning operation of hardened steels with interrupted surfaces because these tools exhibit higher toughness than tools with an added ceramic phase (low CBN content tool). Therefore, the high CBN content of these tools makes them harder than those with a lower amount of CBN. The CBN grade in which part of the CBN content is replaced by a ceramic phase loses in hardness and toughness, but gains in chemical stability. This is important for the finish operations of continuous surfaces, where a high temperature is reached, and diffusive wear must be avoided (Sandvik, 1994). Usually, these tools have a chamfer on the cutting edge to strengthen it and protect it against chipping and breakage [22]. 2. LITERATURE Singh and Rao [1] discussed surface finish, and it was found that it varies when the cutting parameters vary. Statistical analysis of the experiment processed using ANOVA (analysis of variance). Surface roughness increases with the increase of feed rate and depth of cut and decreases with the increase of cutting speed. Diniz and Macaroni [2] used AISI 1045 steel bars with an average hardness 96 HRB along with the vegetable oil as cutting fluid with 6% water concentration. Cutting fluid used at different flow rates, (91 and 111 min -1 ) and pressure 0.04 Mpa. Due to the lubricant application on the tool, the tool life improves as compared to dry cutting and also reduce the temperature formed during turning. In this [3] they used graphite and molybdenum disulphide in powder form having 2 μm average particle sizes as solid lubricants. The solid lubricant was supplied from 0.5 gm/min to 15 gm/min through