Preparation and Lubricating Properties of A New Antibacterial Emulsion Containing Nano-TiO_2 for Cold Rolling Strips

A new kind of emulsion containing nano TiO_2 was developed through the dispersion experiment. A commercial emulsion and a prepared by our lab emulsion without nano particles were chosen as controls to test the tribological and antibacterial properties of this new emulsion. The load carrying capacity, friction coefficient and average diameter of wear scars were tested by a four-ball machine and the comprehensive antifriction parameter ω was calculated. The wetting angle was also tested using a JC200C1 wetting angle tester. The micro surface and roughness of rolled strips were analyzed to investigate the tribological performance of the recommended new emulsion in strip production. It is shown that the new nano-emulsion possesses a higher load carrying capacity and wetting ability. Therefore the abrasive/plowing wear is reduced more efficiently with the addition of nano particles, and the micro surface is improved. The density of bacteria in the emulsions was tested after the cold rolling experiment. The emulsion breaking ratio and bacteria density were also tested in different time intervals after the cold rolling experiment. The final p H values and bacteria density of different layers of emulsions were measured and the sediment was analyzed by TEM to evaluate the antibacterial behavior of this new emulsion. It is shown that the density of microbial colonies which led to a corruption of emulsions was decreased about 90% and the effective antibacterial period was prolonged.

Investigation on Relationship between Lubricating Performance and Stability of Emulsion for Cold Strip Rolling

The influence of the ratio and content of emulsifiers on the stability of anion emulsions for cold strip rolling was investigated in this paper. The present study also investigated the effects of HLB （hydrophile-lipophile balance） value and emulsifier content on the stability of no-ionic emulsions. Based on the effects of different stabilities and different concentrations of emulsions on the adsorptivity and friction coefficients, good lubricating performance was obtained when the amount of the separated oil and soap （SOS） accounted for 2.5%. The wearing scar of the steel balls also indicated the improvements in tribological properties after using the emulsion. Thus, the preparation of emulsion should be regulated according to different rolling conditions.

A new cold rolling lubrication method combining emulsion and neat oil lubrication

The cooling and lubrication process is one of the key processes in cold rolling,as it not only determines surface quality and strip shape,but also reduces the rolling power consumption and extends the life of the roll even during high-speed operation.In this study,an innovative method combining emulsion lubrication and neat oil lubrication was used to solve some problems associated with individual passes.Laboratory tests on stainless steel strips showed that this new lubrication method could improve the surface quality of the strip,control the rolling friction in the deformation zone,and has the potential of making lubrication systems simpler and easier to operate,all while reducing the negative environmental impact from emulsion processing.

Plastic-elastic Model for Water-based Lubrication Considering Surface Force

Water-based lubrication is an effective method to achieve superlubricity,which implies a friction coefficient in the order of 10−3 or lower.Recent numerical,analytical,and experimental studies confirm that the surface force effect is crucial for realizing water-based superlubricity.To enhance the contribution of the surface force,soft and plastic materials can be utilized as friction pair materials because of their effect in increasing the contact area.A new numerical model of water-based lubrication that considers the surface force between plastic and elastic materials is developed in this study to investigate the effect of plastic flow in water-based lubrication.Considering the complexity of residual stress accumulation in lubrication problems,a simplified plastic model is proposed,which merely calculates the result of the dry contact solution and avoids repeated calculations of the plastic flow.The results of the two models show good agreement.Plastic deformation reduces the local contact pressure and enhances the function of the surface force,thus resulting in a lower friction coefficient.

Design and Engineering Application of Direct Mixing Lubrication System for Emulsion Pipeline in Secondary Cold Rolling Mill

With the benefit fierce competition in the steel industry market in recent years,double cold reduction products have been developed towards strength improvement and thickness reduction.The traditional cold-rolling lubrication process with a fixed flow rate and concentration cannot solve the problems,which are uncontrollable plate shape and the excessive consumption of lubricating oil.Moreover,based on the analysis of the traditional direct aplication lubrication system of double cold reduction mill,a set of design scheme suitable for the emulsion pipeline direct mixing lubrication system of double cold reduction mill unit was proposed.The design completed the selection of key components,which included the static mixer and atomization nozzle selection,pump and oil pump design selection,pipeline design selection,flow type selection,pressure gauge selection,electronic control cabinet design selection and other eight aspects.Equipment of the emulsion pipeline direct mixing lubrication system of double cold reduction has been developed.Comparing with characteristics of the traditional direct aplication lubrication system,the emulsion pipeline direct mixing lubrication system was better applied to the production practice of a 1220 double cold reduction mill.The consumption of ton of steel was reduced by 9.6%.The rolling energy consumption and fuel consumption comprehensive costs decreased by 10.7%,and the strip steel section thickness difference was reduced by 19.3%.In addition,the plate shape quality defect rate decreased by 25.6%,otherwise creating a large economic benefit for the unit and promoting the application value.

Tribological behaviors of graphene oxide partly substituted with nano-SiO_(2) as lubricant additives in water for magnesium alloy/steel interfaces

Although graphene oxide(GO)has emerged as an excellent lubricant additive in water,there remain great challenges in their practical application due to high production costs.By taking into account the low cost and also its excellent tribological properties,it is likely that nano-SiO_(2)can be used as a lubricant additive to partially replace GO.Hence,this paper aims to explore the tribological properties of nano-SiO_(2)incorporated in GO nanofluids for partial GO replacement by investigating the friction coefficient and wear volume of the prepared SiO_(2)/GO hybrid nanofluids for magnesium alloy/steel sliding pairs.The experiments reveal that the SiO_(2)/GO hybrids retain low friction coefficients as compared to individual GO or SiO_(2)at all test conditions in this study.However,as for the bearing capacity test,all samples can provide a low wear volume under the loads of 1 and 3 N.With the increase of the normal load,there is considerable differences in the anti-wear behavior.Compared with that of individual GO nanofluids,the wear volume of the GO/SiO_(2)(mass ratio of 0.3:0.2)hybrid nanofluids was reduced by50.5%at 5 N and by 49.2%at 8 N.Furthermore,the wear volume of the GO/SiO_(2)(mass ratio of 0.3:0.2)hybrid nanofluids was reduced by46.3%under the rigorous conditions,as compared to individual GO nanofluids.The findings provide new insights into developing carbon nanomaterial-based hybrid nanofluids for magnesium alloy formation.

DEVELOPMENT AND APPLICATION OF WATER-IN-OIL EMULSIONS FOR ZINC HOT ROLLING

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Synthesis and mechanism of environmentally friendly high temperature and high salt resistant lubricants

With the exploration and development of deep and ultra-deep oil and gas,high torque and high friction during the drilling of deep and ultra-deep wells become one of the key issues affecting drilling safety and drilling speed.Meanwhile,the high temperature and high salt problem in deep formations is prominent,which poses a major challenge to the lubricity of drilling fluids under high temperature and high salt.This paper reports an organic borate ester SOP as an environmentally friendly drilling fluid lubricant.The performance evaluation results show that when 1%lubricant SOP is added to the fresh water-based mud,the lubrication coefficient decreases from 0.631 to 0.046,and the reduction rate of lubrication coefficient is 92.7%.Under the conditions of 210℃ and 30%NaCl,the reduction rate of lubricating coefficient of the base slurry with 1%SOP was still remain 81.5%.After adding 1%SOP,the wear volume decreased by 94.11%compared with the base slurry.The contact resistance experiment during the friction process shows that SOP can form a thick adsorption film on the friction surface under high temperature and high salt conditions,thus effectively reducing the friction resistance.Molecular dynamics simulation shows that lubricant SOP can be physically adsorbed on the surface of drilling tool and borehole wall through hydrogen bond and van der Waals force.XPS analysis further shows that SOP adsorbs on the friction surface and reacts with metal atoms on the friction surface to form a chemically reactive film.Therefore,under high temperature and high salt conditions,the synergistic effect of physical adsorption film and chemical reaction film effectively reduces the frictional resistance and wear of the friction surface.In addition,SOP is non-toxic and easy to degrade.Therefore,SOP is a highly effective and environmentally friendly lubricant in high temperature and high salt drilling fluid.

Experimental Study on Friction Reducing and Anti Wear Property of a Water-Based Lubricant with Polyether Added

The wear behaviors of steel-steel pair on condition of a water-based lubricant with copolymer of acylamino polyoxyethylene polyoxypropylene ether(KE-1)included as additives are investigated with the help of the universal micro-tribotester.Tests on friction and wear are carried out.As a reference,some tests with pure water are also performed for comparison.The results show that the prepared water-based lubricant has a good effect on the characteristics associated with friction reducing and anti-wear processes,which lay some credence to its utilization in practical industrial tribo-systems.

Black phosphorus quantum dots: A new-type of water-based high-efficiency lubricant additive

Black phosphorus quantum dots(BPQDs),obtained via a typical solution-based top-down method,were used as water-based lubricant additives.BPQDs exhibited remarkable friction reduction and anti-wear properties even at the ultra-low concentration of 0.005 wt%,which reduced the friction coefficient and wear volume of the base liquid by 32.3%and 56.4%,respectively.In addition,the load-supporting capacity of the base liquid increased from 120 N to over 300 N.BPQDs-based additives exhibited a relatively long lifetime at a relatively high load of 80 N.The performance of BPQDs considerably exceeded that of the BP;this may be attributed to their small and uniform particle size,good dispersion stability in water,and high reactivity at the frictional surfaces.The results of the surface wear resistance analysis demonstrated that a robust tribochemical film with a thickness of approximately 90 nm was formed on the rubbing surface lubricated with 0.005 wt%of BPQDs dispersion.Moreover,the film served as a direct evidence of the excellent tribological performance of BPQDs.

Tribological performance of various metal-doped carbon dots as water-based lubricant additives and their potential application as additives of poly(ethylene glycol)

Advances in nano-lubricant additives are vital to the pursuit of energy efficiency and sustainable development.Carbon dots(CDs)have been widely investigated in the domain of lubricant additives owing to their extraordinary tribological properties,in particular,their friction-reducing and anti-wear properties.Metal-doped CDs are a new type of CDs,and their friction-reducing and anti-wear properties are attracting increasing attention.Therefore,a series of CDs doped with various divalent metal ions have been successfully synthesized via one-pot pyrolysis.The tribological properties of the synthesized CDs as water-based lubricant additives are in the following order:Zn-CDs>Cu-CDs>>Mg-CDs>Fe-CDs>U-CDs.Specifically,adding 1.0 wt%of Zn-CDs into water-based lubricant results in 62.5%friction and 81.8%wear reduction.Meanwhile,the load-carrying capacity of the water-based lubricant increases from 120 N to at least 500 N.Zn-CDs as an additive have long service life.Additionally,anion-tuned Zn-CDs fabricated via anion exchange exhibit promise as lubricant additives for poly(ethylene glycol).Based on the results of wear scar surface analyses,it is discovered that tribochemical films,primarily composed of iron oxides,nitrides,metal carbonates,zinc oxides,zinc carbonates,organic compounds,and embedded carbon cores,formed on the rubbing surfaces with a thickness of approximately 270 nm when Zn-CDs are used as additives.This film combined with the“ball-bearing”and third-particle effects of Zn-CDs contributed to excellent lubrication performance.

Preparation of an environmentally friendly emulsion-type lubricant based on crude rice bran wax

In this study,crude rice bran wax oil-in-water emulsion(named CRBWE)was prepared by agent-in-water method.The critical factors influencing the sample preparation process were optimized.For instance,the optimum hydrophile-lipophile balance value of compound emulsifier was 12.33–13.40,the content of compound emulsifier was 10 wt%,the emulsification temperature was 70°C–80°C,the agitation speed was 200 rpm,and the emulsification time was 30–45 min.The performances as a lubricant of drilling fluid were also evaluated with respect to lubricity,rheology and filtration loss of CRBWE.The results showed that CRBWE had good lubricity and didn't affect the rheological properties of drilling fluid.For example,when it was added into bentonite dispersion at room temperature with the fraction of 1 wt%,the coefficient of friction of bentonite dispersion dramatically decreased to 0.077,and the coefficient of friction reduced rate was greater than 80%.Overall,these findings indicated that CRBWE would have promising applications as environmental friendly lubricant of drilling fluids to reduce torque and drag in petroleum and natural gas drilling.

Formulation of lyotropic liquid crystal emulsion based on natural sucrose ester and its tribological behavior as novel lubricant

The tribological behavior of oil-in-water emulsions formulated with natural lyotropic liquid crystal(LLC)emulsifiers based on natural sucrose ester was studied for the first time.Polarized optical microscopy,synchrotron radiation small-angle X-ray scattering,wide-angle X-ray scattering,and synchrotron radiation infrared microspectroscopy demonstrated that LLC emulsifiers were tightly ordered at the oil–water interface with a distinct nematic texture.The viscosity of emulsion was observed to change over time.Moreover,the zeta potential and laser particle size distribution verified the emulsion’s satisfactory stability.The frictional shearing test proved that the coefficient of friction of the emulsion versus pure oil decreased by 34.2%.The coefficient of friction of the emulsion with liquid crystal decreased 10.1%versus that without liquid crystal.Although liquid crystal emulsion did not exhibit outstanding anti-wear performance compared with pure oil,its wear volume was 29.4%less than the emulsion without liquid crystal.X-ray photoelectron spectroscopy and scanning electron microscope–energy dispersive X-ray spectroscopy(SEM–EDS)proved that the tribo-film of the emulsion with liquid crystal was formed synergistically by the liquid crystal phase with the base oil.The formulation affecting the lubricant quality was further studied by orthogonal experiments.The resulting Stribeck curve behavior suggested that proper composition with a slightly higher viscosity can better reduce friction in both boundary lubrication and mixed lubrication regimes.The lubrication mechanism indicated that the periodically ordered liquid crystal was transported to the sliding asperity in the form of emulsion droplets,which bored the pressure and released the oil to form a tribo-film.This LLC emulsion is environmentally friendly and potentially non-irritant to the skin.Thus,it has promising application prospects as novel water-based and biological lubricants.

Liquid superlubricity of lubricants containing hydroxyl groups and their aqueous solution under rolling/sliding conditions

Macroscale rolling/sliding conditions are in the superlubricity,a little-studied topic so far.The purpose of this paper is to examine the formation of elastohydrodynamic lubrication(EHL)films by water-based lubricants(glycerol and polyethylene glycol(PEG)),providing superlubricous friction.Experiments were carried out on an optical ball-on-disc tribometer under rolling/sliding conditions.The film thickness was measured by the thin film colorimetric interferometry,and the viscosity of liquids was measured by rotational and high-pressure falling body viscometers.The results show that tribochemical reactions are not the mandatory reason for friction to reach the superlubricity level when using the water-based lubricants.The studied liquids themselves are almost Newtonian.With the addition of water,the signs of shear thinning behavior disappear even more.Suitable conditions for this type of lubricant can be predicted using the known Hamrock–Dowson equations.An anomaly in the thickness of the lubricants was observed as an abrupt change at certain conditions.The more PEG there is in the lubricant,the higher the thickness at the beginning of the jump.

Lubricating properties of oil-in-water emulsion with low oil concentration:Competitive wetting effect

Oil-in-water （O/W） emulsions are widely used in metal working such as hot rolling and cutting. Three kinds of O/W emulsions with low oil concentration were prepared which include conventional emulsion （CE）, miniemulsion （MNE） and microemulsion （ME）. The lubricating properties of O/W emulsions with low oil concentration were investigated using the tribological testers and the thin film interferometry based on the relative optical interference intensity method. The tribological test results under boundary lubrication show that the friction coefficient and the total losing weight can be clearly seen： CE 〈 MNE 〈 ME. The lubricating film thicknesses under elastohydrodynarnic lubrication and thin film lubrication show that a relationship of the film formation abilities： CE 〉 MNE 〉 ME. Competitive wetting behavior of water and oil on solid surface was confirmed to play an important role in the film formation and tribological behaviors of O/W emulsion.

矿物油/蓖麻油混合乳化液条件下车削45钢的性能研究

为了减少工业中矿物油切削液对环境的污染并进一步提高冷却润滑性能,制备了新型矿物油/蓖麻油混合乳化液,并将其与矿物油乳化液和蓖麻油乳化液在浇注和微量润滑条件下进行车削45钢试验,基于力的波动情况分析了切削过程的稳定性,测量了切削力和切削温度,观察了前刀面磨损形貌,并分析了混合乳化液的润滑机理。在此基础上进一步分析了混合乳化液浓度对刀具切削性能的影响。试验结果表明:在浇注和微量润滑条件下,混合乳化液的冷却润滑性能最好。原因是在相同润滑条件下,混合乳化液中的矿物油和蓖麻油在刀—屑界面形成了减摩效果好的协同润滑膜,提高了切削过程的稳定性,降低了刀具的磨损程度。同时发现,随着混合乳化液浓度的增加,切削力、切削温度以及刀具磨损面积逐渐减小,当浓度为20%时,混合乳化液的冷却润滑性能最佳,且刀具的切削性能明显提高。

冷轧带钢表面热划伤缺陷分析及控制

热划伤是冷轧带钢轧制生产中较为常见的一种表面质量缺陷。通过对某冷轧厂酸轧机组一段时期内出现的热划伤缺陷形貌、产生机理和原因进行研究分析,发现热划伤缺陷主要是轧制过程中润滑和冷却不良造成的。经过对带钢发生热划伤缺陷的规律进行跟踪,并采取一系列工艺调整实验验证,结果表明,控制轧辊磨削粗糙度和轧制里程、优化轧制压下率分配、改善工艺润滑条件等是解决热划伤缺陷的有效措施。

棉纱线润滑剂静电吸附行为

考察了棉纱线和润滑剂的Zeta电位,通过测定润滑剂的吸附率,分析两者之间的吸附行为。结果表明:pH在3~10范围内,润滑剂乳液的Zeta电位受pH、润滑剂种类影响较大,棉漂白纱线的表面Zeta电位分布在-25~-20 mV,棉固色纱线的表面Zeta电位分布在10~30 mV;阳离子润滑剂在弱酸性条件下可以被棉漂白纱线充分吸附,中性至弱碱性条件下吸附率仅有6%~11%;弱酸至弱碱性范围内,棉固色纱线对阳离子润滑剂的吸附率仅有12%~22%;弱阴离子润滑剂在中性至碱性条件下可以被棉固色纱线充分吸附,在弱酸性条件下吸附率为67.9%。

Water-based lubrication of niobium nitride

Water-based lubrication has attracted wide attention as an oil-free lubrication method owing to its greener and cleaner lubrication means.However,due to operating in the water environment,most moving parts would inevitably suffer from abrasion,rusting,and aging problems.Developing a novel solid-water composite system with ultra-low friction and wear will open new possibilities for innovative lubrication material research and development.Here,we first revealed the water-based lubrication behavior of a high-hardness niobium nitride coating(NbN).In a three-phase contact environment(water,air,and NbN),oxidation and hydrolytic reactions of NbN result in the formation of"colloidal solutions",containing Nb_(2)O_(5)colloidal particles between the tribo-pairs.Utilizing the double electric layer repulsion and weak shear action of the"colloidal solution",NbN achieves ultra-low friction and wear;the corresponding values are as low as 0.058 and 1.79×10^(-10)mm^(3)·N^(-1)·m^(-1),respectively.In addition,other VB transition metal nitrides(VB TMNs)exhibit the same low friction feature as NbN in the three-phase contact environment;the friction coefficients are even lower than those in an oil-based environment.The water-based lubrication of VB TMNs provides a new reliable scheme for optimizing solid-water composite lubrication systems without additives and is expected to be applied in environments with high humidity or insufficient water coverage.

四辊可逆冷轧机轧制润滑工艺实验研究

在四辊可逆冷轧机上用A,B,C和D 4种冷轧乳化液对St12带钢进行了轧制润滑工艺实验,分析比较了在相同轧制条件下4种轧制乳化液对轧制力、带钢表面反射率、带钢和轧辊表面温度等的影响规律.分析了轧制力和轧制速度的关系,利用实测轧制力数据和数学模型计算得到了摩擦因数.较好的油品润滑能力顺序为B,C,D和A,冷却能力顺序是A,C,D和B,带钢表面反射率顺序是B,D,C和A.实验研究结果对油品开发与评价,优化轧制润滑工艺参数和提高板面质量具有重要的理论和实际意义.