Emulsion Lubrication Research Articles

Potential Controlled Tribological Behavior of Water-Based Ionic Liquids

Increase of energy efficiency, reliability and durability of technical systems in combination with resource conservation using environmentally friendly water-based lubricants would be an overarching goal in all tribological applications. According to this aim the objective of this work is to investigate and identify new water-based lubricants containing ionic liquids (ILs) to reduce friction and wear. Therefore the tribological behavior of different water-based ionic liquid mixtures, compared with a standard water based cooling lubricant emulsion, was studied using a ball-on-disk test. A three electrode setup was used to analyze the influence of different electric potentials. The results show that friction and wear can be improved by using ionic liquid. In addition, the tribological behavior can be strongly influenced by electric potentials. As tribological mechanism the attraction of cations and the formation of a triboactive layer is assumed, due to charging of the surface.

Exploring an alternative aqueous lubrication concept for biomedical applications: Hydration lubrication based on O/W emulsions combined with graphene oxide

Water-based lubrication concepts are of high interest for applications that require friction and wear control in a bio-medical environment. In this work, a concept of aqueous lubrication is presented based on hydration of surface active polymers combined with graphene oxide. Three different kinds of surface-active polymers with or without graphene oxide were coated on a CoCrMo alloy surface, and the samples were characterized by ATR and XPS. Hydration lubrication was created from a tailored oil-in-water (O/W) emulsion. Enhanced friction reducing capability was found for the polymeric coatings in combination with graphene oxide. The tribological behaviour of a PEG-lactide coating in emulsion was better than that of PEG coating, indicating the advantage of using hydrophilic and lipophilic group containing surface-active polymers for emulsion lubrication. The overall maximum reduction in friction that was achieved for a sliding contact of coated engineering surfaces from CoCrMo at low sliding velocity and moderate contact pressure was of about 63% compared to uncoated CoCrMo sliding in water at the same operational conditions.

Boundary lubrication of stainless steel and CoCrMo alloy based on phosphorous and boron compounds in oil-in-water emulsion

Emulsion lubrication is widely used in metal forming operations and has potential applications in the biomedical field, yet the emulsion lubrication mechanism is not well understood. This work explores the possibilities of three different oil-in-water (O/W) emulsions containing dibutyl octadecylphosphoramidate (DBOP), 6-octadecyl-1,3,6,2-dioxazaborocan-2-ol calcium salt (ODOC) and 2-(4-dodecylphenoxy)-6-octadecyl-1,3,6,2-dioxazaborocane (DOB) to generate boundary films on stainless steel AISI 316 and CoCrMo alloy surfaces. Experimental results show lower friction values for the emulsions in combination with CoCrMo compared to AISI 316. The different performance of the additives is related to the composition of the adsorption and reaction film on the interacting surfaces, which was shown to be dependent on the active elements and molecular structure of the additives. The friction profile of the emulsions indicates that the emulsion appears to be broken during the rubbing process, then the additives adsorb onto the metal surface to form protecting boundary layers. The XPS analysis shows that for boundary lubrication conditions, the additive molecules in the emulsion first adsorb on the metal surface after the droplet is broken, and then decompose and react with the metal surface during the rubbing process to form stable lubricating films on the rubbed surfaces

Influence of cryogenic lubrication on the tribological properties of Ti6Al4V and Inconel 718 alloys under extreme contact conditions

ABSTRACTThe proposed paper is focusing on the influence of cryogenic lubrication on friction within the context of machining TiAl6V4 and Inconel 718 alloys with carbide cutting tools. Several wear improvements have been reported in the literature when using liquid or gas nitrogen as cooling‐lubrication fluids compared with dry machining or to conventional emulsion lubrication. However, it is always questionable whether cryogenic lubrication is responsible for a decrease in the cutting temperature or for a decrease in the friction coefficient at the contact interfaces and whether liquid nitrogen lubrication is more effective than gas nitrogen lubrication. In order to simulate the tribological conditions corresponding to those occurring at these interfaces under dry and cryogenic conditions, a specially designed open tribometer has been used to characterise macroscopic friction coefficient, heat transfer and adhesion in the contact for a large range of sliding velocities. Friction, cryogenic, superalloys, heat transfer and adhesion Copyright © 2014 John Wiley & Sons, Ltd.

エマルション圧延油の高効率プレートアウト技術

エマルション圧延油の高効率プレートアウト技術

Recognition and Control of the Influence Factors on the Surface Defects of Cold Rolled Strip with Emulsion Lubrication

In cold rolling, good surface quality should be maintained with the requirement of constant increasing productivity. Oil-in-water (O/W) emulsions are widely used in cold rolled strips due to their good characteristics as lubricants and coolants. The strip surface defect is one of the central quality problems in the rolling process. A poor strip surface quality after cold rolling may have a large impact on the downstream process, like annealing, galvanization and painting. The surface condition could be deteriorated in many forms affected by various factors. However, few reports focused on the effect of the lubricating property of emulsion on the final surface quality. In this paper, the general surface defects of cold rolled strips such as watermark defects, black spot defects, heat scratches and corrosion defects were analyzed by scan electron microscope (SEM) and energy spectrum analysis (EDS) and the morphology and composition of the defects have been researched. The reason of the surface defects generated is analyzed, and the factors which introduce the surface defects during rolling process are presented. Therefore, it has an important significance to identify the features of the surface defects and put forward the solution measures.

Study and Application of Nanomaterials in Drilling Fluids

Due to their special properties, nanomaterials had potential application value, and they could play an essential role in improving mudcake quality, assisting in film-forming, reducing lost circulation, and enhancing wellbore stability. Some nanomaterials, such as nanocomposite filtration-reducing agent, nanocomposite viscosifier, nanosized emulsion lubricant, nanometer organoclay, and so on, were introduced, and all of them had significantly influence on the process of drilling operations. As a result, the application of nanomaterials in the field of drilling fluids are very useful for cleaning borehole, maintaining borehole stability, protecting reservoir, and enhancing oil and gas recovery. Finally, the further application of nanomaterials in drilling fluids is also prospected.

Influence of Plate-out Oil Film on Lubrication Characteristics in Cold Rolling

Oil-in-water (O/W) emulsions are widely used in tandem cold rolling mills as coolants in order to reduce frictional forces and prevent heat scratches. Although the lubricating properties of O/W emulsions are determined by various factors, two particularly important ones are the amount of plate-out oil on the strip surface and the dynamic concentration mechanics of the emulsion at the inlet of roll bite, which has been a subject of much interest since the 1970s.As many studies have focused only on a single phenomenon, it is important to simulate the interaction of the two phenomena as it occurs in actual cold rolling.In this paper, first, a new method of evaluating the relationship between plate-out oil and lubrication characteristics is proposed, which enables control of plate-out oil before rolling.It was found that rolling force decreased when a plate-out oil film was formed before rolling, but the reduction of rolling force was saturated when the amount of plate-out oil exceeded a certain level. The influence of roughness, the roll coolant, and other factors was also examined using the proposed method. In particular, in tandem cold rolling, it is necessary to consider the influence of plate-out oil carried over by the preceding stand on the lubrication characteristics of the following stand.The results of this research suggest that it is possible to clarify the mechanism of emulsion lubrication using the proposed method.

Investigation of the Tribological Characteristics of ZCuPb20Sn5 and No.45 Steel under Emulsion Lubrication

As friction pair, ZCuPb20Sn5 and No.45 steel are most in use in gear motor under oil lubrication. In order to investigate the tribological characteristics of ZCuPb20Sn5 and No.45 steel under emulsion lubrication, the authers tested them on MMW-1 friction and wear tester with sample pin and thrust ring. The relationships between the friction coefficient and the load, the friction coefficient and the speed, the wear rate and the load, the wear rate and the speed were provided. The worn surface of ZCuPb20Sn5 were investigated by means of scanning electron microscope. The results showed that, alone with the raising of the load and the speed, the wear rate of ZCuPb20Sn5 increased, but the friction coefficient reduced.

Experimental study on wear and friction of work roll material with 4% Cr and added Ti in cold rolling

Abstract Cold rolling is one of the most essential elements in the manufacture of flat products of metals. Work roll wear is always a topic of interest to many researchers. In this paper, the disc-to-disc tests of the material with 4% Cr and that with 4% Cr + Ti were carried out respectively under the conditions of dry contact and emulsion lubricant of 3.9% Quakerol N680-2-DPD. The wear and friction patterns were discussed by correlating the disc surface morphologies and the microstructures of both materials. The surface roughness of the disk of the material with 4% Cr + Ti deteriorates much slower than that with 4% Cr under the condition of lubrication. The material with 4% Cr + Ti is characterised as carbonitrades precipitated in a fine tempered martensite matrix while coarse carbides (M 7 C 3 ) exist in the material with 4% Cr. The disk of the material with 4% Cr + Ti wears differently to that with 4% Cr. Delamination may become an important wear mechanism earlier in the case of 4% Cr than that of 4% Cr + Ti. Micro spalling and pitting occur after 120 min of wear in the case of 4% Cr, but not in the case of 4% Cr + Ti until 330 min. Detached carbides are responsible for the abrasive wear on both discs at the late stage. Ti alters the friction pattern due to surface regeneration that resulted from the abrasive effect of carbonitrades. Generally, the wear-resistance of roll material may be improved by 175% by introducing added Ti. The outcome is beneficial for developing new materials for prolonging the service life of the cold work roll.

Biological protection of lubricant and coolant emulsions

Biological protection of lubricant and coolant emulsions

Influence of Plate-out Oil Film on Lubrication Characteristics in Cold Rolling

Oil-in-water (O/W) emulsions are widely used in tandem cold rolling mills as coolants in order to reduce frictional forces and prevent heat scratches. Although the lubricating properties of O/W emulsions are determined by various factors, two particularly important ones are the amount of plate-out oil on the strip surface and the dynamic concentration mechanics of the emulsion at the inlet of roll bite, which has been a subject of much interest since the 1970s.As many studies have focused only on a single phenomenon, it is important to simulate the interaction of the two phenomena as it occurs in actual cold rolling.In this paper, first, a new method of evaluating the relationship between plate-out oil and lubrication characteristics is proposed, which enables control of plate-out oil before rolling.It was found that rolling force decreased when a plate-out oil film was formed before rolling, but the reduction of rolling force was saturated when the amount of plate-out oil exceeded a certain level. The influence of roughness, the roll coolant, and other factors was also examined using the proposed method. In particular, in tandem cold rolling, it is necessary to consider the influence of plate-out oil carried over by the preceding stand on the lubrication characteristics of the following stand.The results of this research suggest that it is possible to clarify the mechanism of emulsion lubrication using the proposed method.

The Influence of Lubricating Agents on the Formation of a Film of a Styrene/Butadiene Latex

The interactions between paper coating lubricants and a carboxylated styrene/butadiene latex emulsion and their effect on latex film morphology have been studied. Calcium stearate, non-ionic polyethylene emulsion and organic triglyceride lubricants showed different interaction characteristics with the latex emulsion according to viscosity, zeta potential and isothermal calorimetric measurements. Calcium stearate lowered the viscosity of the dilute latex emulsion at low concentration suggesting a strong interaction with the latex particles due to a change in the hydrodynamic dimensions of the latex particles. The exothermic enthalpy change supported the assumption of a dissociative interaction. In contrast, both non-ionic polyethylene and organic triglyceride emulsion showed less pronounced enthalpy changes, indicating lower affinity for the latex particles. The reduction in viscosity showed, however, that at low lubricant concentrations there is an interaction between the latex particles and particularly the organic triglyceride emulsion. This suggests a selective adsorption of stabilizing agents and species from the lubricant emulsion which alters the hydrodynamic radius of the latex particles. The effects of the colloidal interactions on the morphology of the latex films monitored by Atomic Force Microscopy (AFM) indicated that specific surface interaction occurring in aqueous media influenced the topography and the surface chemical heterogeneity of the latex films. Especially in the case of calcium stearate, it seems that the dissolved species arrange themselves around the latex particles inhibiting film formation. The organic triglyceride, on the other hand, showed a lower interaction potential in the aqueous phase and it had a different impact on the film formation.

Numerical Simulation of an Oil Particle in Emulsion Lubrication

The analogy of lateral particle migration in shear flows has been used to investigate the entrainment of oil particles in the inlet region where a Poiseuille flow is assumed. Previous researchers have studied the particle segregation positions and the particle size effect through two-dimensional simulations. In this paper, both two-dimensional and three-dimensional simulations were conducted. The two-dimensional analysis showed that there are two stable off-center segregation positions and one neutrally stable center segregation position for the small particles, while only one stable center segregation position was found for the large particles. The results are similar in three-dimensional simulations except that the center segregation position is more stable than in the two-dimensional case. It should be noted that all the segregation positions are within the backflow region, which means all the oil particles will be rejected from the contact region if the interparticle collisions are ignored. This is supported by experimental observations.

Cold rolling mill process: a numerical procedure for industrial applications

The paper proposes a model for a cold rolling mill process in the full-film regime that uses lubricant emulsion sprayed on at the entrance of the strip. The aim of the model is to forecast the reduction of strip thickness versus the flow rate of lubricant given the other operation parameters. The model includes strip plastic deformation, lubricant flow and lubricant viscosity depending on pressure. The mathematical problem is a free boundary one and a numerical procedure, applied to an industrial plant, is presented with some results.

Multicomponent quantification with a novel method applied to gradient gas sensor microarray signal patterns

Abstract Industrial monitoring can be performed efficiently by an electronic nose (EN) not only in case of direct gas analysis but also if liquids have to be analysed for volatile components. The control of a binary biocide mixture contained in oil–water emulsions is presented as an example for a multicomponent quantification. A carrier gas was bubbled through the lubricant emulsion at elevated temperature to enhance the evaporation of the two biocide components to be determined by a gradient gas sensor microarray. A linear discriminant analysis trained with well-defined model mixtures showed a reasonable multicomponent quantification with a special two-dimensional interpolation.

Experimental and numerical study of O/W emulsion lubricated strip rolling in mixed film regime

An experimental and numerical study of cold rolling lubricated by O/W emulsion has been carried out. The strip rolling experiment was carried out on a Hille experimental rolling mill with a view to study the performance of emulsion lubrication in terms of practical rolling parameters. Accordingly, rolling parameters such as rolling force and torque were measured. The experimental measurements compare favourably with the computed results from a numerical scheme developed by the authors. The scheme, based on a two-phase lubricant model, is capable of calculating the oil concentration at any point within the inlet zone and work zone, rolling pressure, film thickness, and fractional contact area ratio associated with strip rolling under mixed film lubrication at different rolling speeds. Using this scheme, the intertwined effects of an emulsion’s parameters such as: oil concentration, mean oil droplet size, and rolling speed on strip rolling were investigated. The numerical study encompassed the mixed film regime for speed, S ranges from 10−4 to 10−2, supply oil concentration level λds from 1 to 10%, and oil droplet size D S from 5 to 10. Experimentally, the differences between water, oil and emulsion-lubricated rolling are not discernible except for film thickness. At a low speed of 10 RPM, force and torque of water-lubricated rolling are marginally higher than oil- or emulsion-lubricated ones. However, the difference between emulsion and neat oil is not apparent. The numerical results show the occurrence of a moderate oil concentration increase in the inlet zone followed by a sharp one at the beginning of the work zone. The effect of the concentration process is predominantly seen in the film thickness and the lubricant pressure whilst its effect on the total pressure is less pronounced. The analysis of the results suggests that it is possible to lower the emulsion oil concentration without any adverse effect on the rolling process. This principle can be used to control the outlet lubricant film thickness and hence the surface quality of the rolled strip.

Viscosity Ratio Effect in the Emulsion Lubrication of Soft EHL Contact

Many foodstuffs and personal care products consist of two-phase systems which, during use, are rubbed between compliant biosurfaces to form thin lubricating films. It is important to understand the nature and properties of the films thus formed since these contribute to the user’s sensory perception, and thus appreciation, of the products concerned. In this paper, the lubrication properties of simple oil-in-aqueous phase emulsions are studied in a steel/elastomer “soft-EHL” contact. It is found that overall behavior is strongly dependent on the ratio of the viscosities of the two phases. When the viscosity of the dispersed oil phase is lower or comparable to that of the continuous aqueous phase, the latter enters the contact and controls film formation and friction. However, when the dispersed phase has viscosity at least four times larger than the dispersion medium, the former enters the contact and determines its tribological properties. This effect is believed occur because at high viscosity ratios the droplets are nondeformable and are thus forced into the contact inlet region, where collisions occur that result in shear-induced coalescence. Once a pool of viscous fluid is formed, the lower viscosity bulk fluid is unable to displace it because the viscous shear stress is too small, so the pool acts as a reservoir to supply the contact.

The effect of emulsifier concentration on the lubricating properties of oil-in-water emulsions

Although the use of oil-in-water (O/W) emulsions as metalworking fluids is widespread, the mechanisms of emulsion lubrication are not yet well understood. Several theories have been proposed but there is not a clear agreement about the effect of different operating conditions and emulsion properties on the lubricating performance of O/W emulsions. In the present study, the film forming ability of O/W emulsions as a function of emulsifier concentration is studied. The emulsifier content exerts a strong influence on all the emulsion properties, such as stability, droplet size distribution, surface and interfacial tension, wetting ability, etc., as well as on the lubricating behaviour, so it has been used to ascertain the relationship between all the properties involved. Three different emulsifiers—anionic, nonionic and cationic—were used at different concentrations in the design of lubricant O/W emulsions. Experimental results show that the work of adhesion of oil droplets on the metal surface is a valuable parameter to predict the ability of emulsions to form thick films in elastohydrodynamic (EHD) contacts. The influence of pH value of O/W emulsions on their lubricating behaviour is also verified. The overall conclusion is that the interactions between metal and oil droplets rule the mechanism of lubrication and that this interaction is primarily controlled by emulsifier concentration.

An elasto-plasto-hydrodynamic model of strip rolling with oil/water emulsion lubricant

We review the problem of metalworking lubrication and include the hitherto much neglected elastic deformation in our analysis. This analysis is carried out for both pure oil lubricant and for lubrication with oil-in-water emulsion. For the latter, we make use of the extended Reynolds equations of Al-Sharif et al. (Ph.D. dissertation, University of Pittsburgh, 1992), which were derived for lubrication with binary mixtures of Newtonian fluids. The results of this paper demonstrate several experimentally observed phenomena of metalworking lubrication, the most significant being that an increase in the value of the elastic modulus enhances oil pooling ahead of the roll bite and results in a thicker film in the working zone.