International Journal of Engineering Research ISSN:2319-6890)(online),2347-5013(print) Volume No.4, Issue No.3, pp : 102- 104 01 March. 2015 IJER@2015 Page 102 Experimental Investigation on Effect of Grinding Direction on Wear Under Heavy Load and Slow Speed Conditions with Molybdenum Disulphide (MoS 2 ) as Additive in Commercial Lubricant S. M. Muzakkir 1 , Harish Hirani Department of Mechanical Engineering, Indian Institute of Technology Delhi, India 1 Corresponding Author Email:mez108659@mech.iitd.ac.in Abstract— In the present work, experimental investigation has been carried out to identify the effect of grinding direction on the wear of the sliding surfaces subjected to heavy load and low sliding velocity with molybdenum disulphide MoS 2 as additive in commercial lubricant. The conformal block and disk test setup has been used to conduct experiments on conformal blocks with two grinding directions: one along the direction of sliding and other across the direction of sliding. The wear of the block is measured as its weight loss after the test. The results of the experiments are reported. Keywords—Wear, grinding direction, lubricant additive, molybdenum disulphide I. Introduction The sliding surfaces contact each other under the operating conditions of heavy load and slow speed and the mixed lubrication regime is operative. Journal bearings of sugar mill [1] etc operates in mixed lubrication regime. The nature of the contacting surfaces dominantly affects the friction and wear behavior of the contacting tribo-pair under these conditions. The amount of wear of the sliding surfaces is dependent on the surface roughness and the grinding direction. This aspect has been the focus of many studies in past. Staph et al. [2] have experimentally indicated that both the surface roughness and surface texture affects the frictional behavior of the contacting surfaces. Maatta et al. [3] in a study on stainless steel strips have shown that friction is affected by surface topography. Experimental study by Marcus et al. [4] showed that the wear is dependent on surface roughness and grinding direction of the sliding surfaces. Lakshmipathy and Sagar [5] studied the effect of directionality of die grinding marks on friction and found that friction factor was less with criss-cross ground pattern. In another study by Blau et al. [6] the wear rate was shown to be dependent on the direction of grinding. Franklin and Kracker [7] have also shown that the wear rate is dependent on the orientation of the grounded surfaces. However, Rasp and Wichern [8] in an experimental study found that surface roughness and lubrication regime have greater influence on friction than directionality. Hu and Dean [9] showed that reduction in friction occurs due to lubricant retention in smooth surfaces. Nosar et al. [9] in an experimental study showed that severe wear occurs when sliding takes places perpendicular to the grinding direction. In another study, Muzakkir and Hirani [10] showed that molybdenum disulphide particles when used as lubricant additive substantially reduces the wear of the sliding surfaces. Muzakkir et al [11] have also experimentally showed that zinc particles used as additives in lubricant minimizes the wear. Very few studies have dealt with the effect of using molybdenum disulphide (MoS 2 ) as solid lubricant additive on the wear corresponding to the grinding direction under mixed lubrication regime. Since most of the bearing inner surfaces are produced by grinding process to obtain a better surface finish, a consideration with respect to the direction of grinding is essential for reducing the wear. However many other relevant factors needs consideration for a comprehensive design of a journal bearing [12] in addition to the grinding direction. The effect of manufacturing variability also affects the magnitude of wear [13]. The complete process of optimum design of the journal bearing may also be carried out by employing the multi-objective criterion [14]. In the present experimental investigations, comparative study have been carried out to study the effect of using molybdenum disulphide (MoS 2 ) particles (technical superfine grade: 1.75 μm size) particles in a commercial lubricant on the wear of conformal block with two grinding orientations. The wear tests were conducted on conformal blocks that were fabricated with final grinding obtained in two mutually perpendicular directions, one along the direction of sliding (represented by 0° orientation) and other across the direction of sliding (represented by 90° orientation). The results of the experiments are reported. II. Experimental Details In the present work, wear tests were carried out on a conformal block and disk test setup. The photograph and schematic diagram of the test setup is shown in figure 1(a) and 1(b). Figure 1(a) Photograph of conformal block and disk test setup [13]