Steel Ball Surface Research Articles

An Evaluation of the Tribological Behavior of Cutting Fluid Additives on Aluminum-Manganese Alloys

The introduction of additives enhances the friction and wear reduction properties of cutting fluids (CFs) as well as aids in improving the surface quality of the machined parts. This study examines the tribological behavior of polymer-based and phosphorus-based additives introduced into cutting fluids for the machining of Al-Mn alloys. Ball-on-disc tests were used to evaluate the coefficient of friction (COF) and lubrication failure temperature to study the performance of the additives in the cutting fluids. Surface characterization was performed on the sliding tracks induced on the Al-Mn disc surfaces and used to propose the wear and friction reduction mechanisms. The polymer-based additive possessed a higher temperature at which lubrication failure occurred, displayed comparable COF at a lower temperature under certain conditions, and possessed a steadier tribological behavior. However, the phosphorus-based additive was observed to display lower COF and wear damage from 200 °C till failure. The lower COF values for the phosphorus-based additive at 200 °C corresponded with lower surface damage on the Al-Mn surface. The phosphorus-based additive’s performance at 200 °C could be attributed to the forming of a phosphorus-rich boundary layer within the sliding wear track, resulting in less surface damage on the Al-Mn surface and lower material transfer to the counterface steel ball surface.

Enhanced Lubrication Ability of Polyalphaolefin and Polypropylene Glycol by COOH-Functionalized Multiwalled Carbon Nanotubes as an Additive

In the current study, the tribological performance of two different synthetic lubricants, i.e., polyalphaolefin (PAO 100) and polypropylene glycol (PPG 2000), were analyzed. The COOH-functionalized multiwalled carbon nanotubes (MWCNTs) were used as an additive in varying fractions (0.025-0.15 wt.%). The friction and wear studies were carried out as per ASTM D6425 by using SRV 5 tribometer with a ‘ball on disk’ configuration. The results showed that tribological performance gets enhanced remarkably with the inclusion of MWCNTs in both lubricants as compared to the pure lubricants. PAO 100 demonstrated the lowest coefficient of friction and wear volume at a concentration of 0.025 and 0.05 wt.% of MWCNTs, respectively. However, 0.025 wt.% of additive in PPG 2000 exhibited the maximum reduction in the coefficient of friction (~6%) and wear volume (~86%). The results confirmed that PAO 100 showed better tribological performance as compared to PPG 2000. The lubrication mechanism of MWCNTs has been demonstrated through the investigation of worn steel ball surfaces by using various characterization techniques such as scanning electron microscope, energy-dispersive x-ray spectroscopy (EDS) and scan probe microscope.

Preparation of powder coatings on the surface of steel balls by mechanochemical synthesis

This work presents the results of the study of tribological and corrosion properties of powder coatings based on VN, TiN, SiC and Cr2N obtained by mechanochemical synthesis on the surface of steel balls ShKh15. The idea of this method is using the impact energy of moving balls to apply coatings on metal surfaces. Based on the conducted research, it was proved using the method of mechanochemical synthesis possible to obtain a coating of VN, TiN, SiC, and Cr2N on the surface of steel balls. The optimal parameters for coating were chosen: amplitude of the oscillation 3.5 mm; frequency of the oscillation 50 Hz; volume of filling of the chamber 50 %, the diameter of the ball 6 mm; ratio mass of the powder to the mass of the balls mp:mb=1:30, processing time by mechanochemical synthesis is 1 hour. It is established that the change in the characteristics of coatings directly depends on the stiffness and physical and mechanical properties of the source material (substrate) and surface roughness. The results of the tribological study showed that a wear-resistant coating was formed on the surface of the steel balls.

Tribological performance and mechanism of 2D calcium borate nanoslice capped with stearic acid in rapeseed oil

Two-dimensional (2D) calcium borate nanoslice capped with stearic acid (abbreviated as SACB) was synthesized by hydrothermal method. The microstructures of as-synthesized SACB were characterized by means of SEM, TEM, XRD, FTIR, and TG, respectively. The water contact angle was also tested. The friction-reducing and antiwear performances of SACB in rapeseed oil were evaluated on a four-ball tribotester and compared with those of the T202-doped rapeseed oil. Furthermore, the morphology, elemental composition, and tribochemical characteristics of worn surfaces were investigated by SEM and XPS. Results showed that the hydrophobic SACB displayed a slice-like morphology with a thickness of about 20 nm and a length in the range of 200 nm to several µm, and exhibited excellent dispersing stability in rapeseed oil. In the meanwhile, the friction-reducing and antiwear abilities of rapeseed oil were enhanced obviously by addition of SACB, and rapeseed oil blended with 0.5 wt% of SACB provided the optimal reduction in friction and wear. The predominant friction-reducing and antiwear abilities of SACB in rapeseed oil were ascribed to the generation of a composite boundary lubrication film mainly composed of the adsorbates of rapeseed oil and SACB nanoslices as well as the tribochemical reaction products of CaO, B2O3, Fe2O3, Fe3O4, FeB, and FeO on the worn surfaces of steel balls.

Visualization Experiment and Numerical Analysis of Cavitation Flow Characteristics in Diesel Fuel Injector Control Valve with Different Structure Design

Increasing the injection pressure has been proven an effective method to enhance performance and reduce pollutant of diesel engine. With the increase of the injection pressure, the cavitation damage problem inside common rail fuel injector is more significant, which has direct influences on reliability of diesel engine. While the most studies so far have focused on cavitation occurred in injector nozzle and its atomization characteristics, few researchers studied the cavitation phenomenon in fuel injector control valve. But due to the complexity of flow field and difficulty of experiment, the cavitation in control valve could not be fully described by existing theories. In this paper, the two-dimensional visualization experiment and numerical simulation of control valve was implemented to acquire the image of cavitation intuitively and validate the simulation method and model. Then a new structure design of control valve named convergent model was presented for comparison. The origin model and convergent model with different valve lifts were simulated in three dimensions. The results showed that the sheet cavitation occurred at the surface of seal cone and steel ball then turned to cloud cavitation in downstream area. The intensity of cavitation increased with the increase of valve lift. Convergent model could efficiently reduce the cavitation intensity near the seal area. This research could provide references for engineering optimization design of control valve.

Coupling hybrid of HBN nanosheets and TiO2 to enhance the mechanical and tribological properties of composite coatings

Epoxy resin (EP) composite coatings enhanced with hexagonal boron nitride (HBN) nano-sheets, TiO2 particles and HBN-TiO2 hybrid material were fabricated successfully on the surface of 304L stainless steel. The structural and morphological features of HBN, TiO2 and HBN-TiO2 hybrid obtained from mechanical peeling and sol-gel method were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), Raman spectroscopy, XRD patterns, FT-IR spectra and XPS spectra. Moreover, tribological characteristic of composite coatings was investigated by UMT-3 tribometer. Mechanical behavior, worn surface, steel ball surface and debris size distribution of composite coatings were detected to investigate the tribological mechanism. The results demonstrated that HBN/EP, TiO2/EP and HBN-TiO2/EP composite coatings showed remarked promotion of mechanical behavior compared with the neat EP, especially for the improvement of hardness. The HBN-TiO2/EP composite coating, whose wear rate decreased by 65.8 % in comparison with the neat EP, manifested prominent tribological performance ascribed to the load carrying capacity of TiO2 and the reduction of self-lubricating effect on the size of debris.

Superlow friction of amorphous diamond-like carbon films in humid ambient enabled by hexagonal boron nitride nanosheet wrapped carbon nanoparticles

The friction and wear of amorphous diamond-like carbon (DLC) films will dramatically increase with the increment of ambient humidity. This drawback can lead to lubrication failure, which greatly impedes the practical applications of DLC films in humid environment. Herein, a simple method is proposed to improve the tribological performance of DLC films in humid environment by adding hexagonal boron nitride nanosheet wrapped carbon nanoparticles (CNP@h-BNNSs) as lubricants. The reciprocating friction tests demonstrate that DLC films with CNP@h-BNNSs as lubricants possess excellent antifriction and antiwear performance at the relative humidity (RH) of 7.5–55%. Especially, it can achieve a superlow friction and wear at the RH of 45–55% which decrease by respectively 13 and 25 times as compared to those obtained from DLC films without lubricants. The investigation on the steel ball surface after friction test shows that a protective tribo-layer containing carbon, boron and nitrogen elements is formed. The existence of this tribo-layer can effectively reduce the friction and protect the steel ball surface from excessive wear. Noteworthy, the h-BNNSs are exposed at the friction interface acting as lubricating layer while the carbon nanoparticles are adsorbed on steel ball surface playing as binding binder. Furthermore, the ball movement mode of CNP@h-BNNSs and the interaction between water molecules and CNP@h-BNNSs are also considered as key factors to reduce friction. All these results indicate that CNP@h-BNNSs which can be massively produced have the potential to reduce the friction and wear of DLC films in humid environment.

Tribological Investigation of Multilayer Graphene as Lithium Grease Additives

As an advanced antiwear and friction reducing material, graphene has been widely studied and applied in many fields. In this study, the tribological characteristics of lithium grease with multilayer graphene (MLG) additive were studied on a four-ball tester. The micro-morphologies and elemental distributions of the wear surfaces of steel balls were identified by FESEM and EDAX. The tribological properties of grease were obviously improved by MLG additive. When the content of MLG was 0.1 wt%, the improvement effect was the best. The coefficient of friction and the wear scar diameter (WSD) decreased by 22.6% and 9%, respectively, at 686 N and 1450 rpm as compared to the original lithium grease. Because of the layered structure of graphene along with its high strength and surface activity, a layer of lubricating film which was favorable for improving the anti-friction and anti-wear property of the friction pair was formed on the friction surface during the friction process.

Tribological Property Study of Xanthate Acetic Ester in Hydrogenated Oil

Xanthate was used as an initial reactant to synthesis two kinds of novel xanthate-containing acetic ester additives (HX and OX), and a four-ball machine was used as tribological tester to appraise their tribological behaviors in hydrogenated oil (10cst). The test results indicated that the as-synthesized additives possess good extreme pressure, antiwear and antifriction properties. The shorter carbon chains acetic ester, the better tribological properties the higher sulfur content. The action mechanism was estimated by analysis of the XPS (X-ray photoelectron spectroscopy) and SEM (scanning electron microscope) results of the worn steel ball surface, and the results illustrated that the protective film containing ferric sulfide and ferric sulfate compound was formed on the worn steel ball surface by xanthate acetic ester , and the protective film has good tribological properties.

A survey of non-destructive techniques used for inspection of bearing steel balls

Bearing steel ball is the basic part of rolling bearing, and its surface quality has a vital impact on the service performance, life and safety of rolling bearing. Therefore, the surface quality of bearing steel balls must be fully tested before leaving the factory. The unfolding mechanism and inspection sensor of steel ball surface are mainly described in this paper. First of all, the inspection methods of steel ball surface quality are analyzed in detail, including visual inspection, eddy current inspection, optical fiber sensor inspection, capacitance sensor inspection, ultrasonic sensor inspection, etc. Then, the methods of steel ball surface unfolding methods are introduced, including meridian unfolding method, one-dimensional orbit unfolding method, disk unfolding method, one-dimensional wheel unfolding method and rotating magnetic field unfolding method. Finally, the future development direction of steel ball detection technology is pointed out, which provides theoretical basis and technical reference for the realization of bearing steel ball surface micro-defect inspection system.

Study of Tribological Synergistic Effect of N-Containing Heterocyclic Borate Ester with Tricresyl Phosphate as Rapeseed Oil Additive

Abstract A single borate ester additive sometimes fails to meet the requirements of modern working conditions, it needs two or more additives for the use. Two N-containing heterocyclic borate esters, 2-(1H-benzotriazol-1-yl) ethyl bis(2-aminoethyl) borate (BEB) and bis-(2-amionethyl) (2-benzothiazol-2-ylthio)ethyl borate (MEB) have been synthesized. Their tribological properties were studied by a four-ball tester after mixing with tricresyl phosphate (TCP) in rapeseed oil (RSO). The results show that these complex additives have strong synergistic effects on load carrying and anti-wear properties. At a mass ratio of BEB (MEB) to TCP of 0.5:0.5, the load carrying capability (PB value) of RSO can be improved by 160.6 % and 204.2 %, respectively. At the same mass ratio, the load carrying capability of the complex additive from the TMx series (MEB with TCP) was better than that of the TBx series (BEB with TCP). The anti-wear effect of TBx was better than that of TMx at high load. The friction reduction of 196 N showed little difference because of the small difference in physical adsorption capacity between TCP and BEB (MEB). The analytical results of Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS) on the worn steel ball surfaces showed that the complex additives were adsorbed on the lubricating surface and formed a stable protective film during the sliding process due to absorption and tribochemical reactions between the borate ester, TCP and metal surface which helped to improve the tribological properties of RSO.

Testing research on friction and wear performance of microstructure surface of unfolding wheel for bearing steel ball detection

The unfolding wheel of AVIKO series steel ball surface quality automatic detector is expensive and easy to wear, which seriously restricts its application and development. In this paper, the wear reason and motion form of the unfolding wheel are analyzed, the unfolding contact model is simplified reasonably, and the corresponding experimental equipment and scheme are designed. The microstructures with different shape parameters are machined on the test pieces surface by laser machining technology, and the theoretical calculation formula for the weight of wear is obtained through friction and wear tests and data fitting. The test results show that compared with the smooth test piece, the test pieces with microstructure surface can increase the friction coefficient and reduce the degree of wear, and the diamond microstructure has the best effect on reducing the wear weight. The fitted formula provides theoretical and experimental basis for the follow-up research and the design of microstructure parameters of unfolding wheel.

Tribological Behaviour of Neem Oil with and without Graphene Nanoplatelets Using Four-Ball Tester

The present work was aimed to study the friction and wear behaviour of graphene nanoplatelets (GNPs) under extreme pressure conditions as an anti-weld additive for neem oil. The effect of neem oil, blended with various loading of GNPs on the friction and wear characteristics has been investigated. From the experimental results, it was found that 1 wt.% of GNPs in neem oil showed the least coefficient of friction and smoother wear scar diameter. The extreme pressure test was performed on neem oil with and without GNPs as per ASTM standards. The extreme pressure test results indicated the improvement in seizure load of neem oil by 27.8% at 0.5 wt.% of GNPs as compared to pure neem oil. Optical microscopy of worn steel ball surface revealed the pit formation and the formation of wedge cutting edge in GNPs modified neem oil.

The tribological properties of lanthanum borate nanoparticles with different morphologies as lubricant additive in rapeseed oil

Sheet-like, Petal-like and Ball-like lanthanum borate nanoparticles were prepared by hydrothermal method (abbreviated as SLBN, PLBN and BLBN, respectively). The morphologies in rapeseed oil (abbreviated as RO) were characterized by scanning electron microscope (SEM). The antiwear and friction-reducing performances of lanthanum borate nanoparticles in rapeseed oil were evaluated on a four-ball tribo-tester. Moreover, the worn steel ball surface was investigated by SEM, X-ray photoelectron spectroscopy (XPS) and Surface Profiler. The result shows that PLBN and SLBN have a thickness of 10nm and 30nm, which exhibits excellent dispersing ability in rapeseed oil, and BLBN have a diameter of 50-120nm. Furthermore, PLBN show a better friction-reducing and antiwear performance. Meanwhile, 2D appearance indicated the worn steel ball lubricated with RO+SLBN have the more shallow and narrow scratches, which consistent with 3D topography. The excellent friction-reducing and antiwear performances attribute to tribochemical film, which contains B2O3 and La2O3.

Enhancement of friction performance enabled by a synergetic effect between graphene oxide and molybdenum disulfide

Graphene-related materials and molybdenum disulfide (MoS2) are good candidates as solid lubricants owing to their easy-shear property between lattice layers. However, the coefficients of friction (COFs) of graphene or graphene oxide (GO) are not sufficiently low at the macroscale and the friction and wear performance of MoS2 is significantly deteriorated by humidity. Herein, GO–MoS2 nanocomposite film is fabricated on a stainless steel (SS) substrate by a simple electrophoretic deposition (EPD) method in water. The deposited nanocomposite film can reduce the COF to 10% of that for a SS substrate and 50% of that for a pristine GO film and can extend the lifetime in comparison to a MoS2 film under ambient conditions. A tribofilm forms in the wear track where GO nanoflakes wrap MoS2 nanoflakes in the tribofilm; furthermore, a MoS2 transfer layer forms on the steel ball surface during the friction test. This excellent lubrication performance arises from the synergetic effect between GO and MoS2, where the layered MoS2 dominates the lubrication performance owing to its easy-shear property and the surrounding GO protects MoS2 from humidity and oxidation. This has implications for developing nanocomposite films with excellent lubrication and wear-resistance performance for industrial applications.

A method of steel ball surface quality inspection based on flexible arrayed eddy current sensor

In order to perform the rapid and efficient automatic on-line inspection of the surface quality of steel ball, a new spherical deployment method based on flexible array eddy current sensor (FAECS) is proposed. Full unfolding of the steel ball surface can be performed by combining the flexible array eddy current sensor with the one-dimensional orbital deployment. The inspection coil of array eddy current sensor is fabricated on flexible printed circuit board (FPCB), which is bent into a semicircle to fix on the top of one-dimensional track. When the steel ball rolls on the one-dimensional track, complete inspection of steel ball surface can be performed by the flexible array eddy current sensor. In this method, one-dimensional mechanical motion is used instead of the traditional two-dimensional deployment motion, which reduces the complexity and cost of deployment structure. Three typical defects include linear cracks (0.12 mm width × 0.5 mm depth), cross cracks (0.06 mm width × 0.9 mm depth) and arc cracks (0.05 mm width × 0.1 mm depth) are measured in the experiment to verify the effectiveness of the inspection system. Subsequently, same batch of steel balls are tested at speed of 4 pcs/s, results show that the inspection accuracy of surface defect of steel balls is 95.52%, and the false inspection rate is less than 0.7%, which proves this method efficiency.

Friction and wear behavior of PTFE coatings modified with poly (methyl methacrylate)

To achieve self-lubricating coating of polymer-based composite coatings with low coefficient of friction (COF) and high wear resistance, the core-shell structure was introduced via a seeded emulsion polymerization to improve wear resistance and self-lubricating properties of the coating. The effect of polytetrafluoroethylene (PTFE) encapsulated by polymethylmethacrylate (PMMA) shell on its wear resistance and lubricating properties under reciprocating dry friction was investigated. The experimental results revealed interesting examples of: the wear rate of PTFE coating was decreased from 232 × 10−6 mm3/Nm to 1.04 × 10−6 mm3/Nm and the COF decreased from 0.081 to 0.069. During reciprocating sliding tests, the results show that a continuous, uniform and thin PTFE/PMMA composite film is transferred to the GCr15 steel ball surface. It was demonstrated that the improved lubricating performance was associated with the dispersion effect from core-shell structure, which has a characteristic size in the nanometer range, and composite thus possess a much higher uniformity and higher dispersivity of reinforcement phase than do composite obtained by the conventional filling method.

The effect of steel ball diameter variation in dry shot peening process on surface roughness and corrosion rate of AISI 316L implant material

Stainless steel, or also called as inox steel is a material that has a resistivity to the oxide reaction in an oxygen-containing environment. This study uses AISI 316L stainless steel material which is a biomedical implant as a raw material that obtains surface modification technique to obtain new mechanical properties. Surface modification technique uses dry shot peening process by varying steel ball diameter as an abrasive material shot on the surface of steel ball at high speed. The steel ball used is AISI 440 C type with a hardness level of HRC 50-55. The results show that the level of material surface roughness will decrease along with the increasing (bigger) size of steel ball diameter used. The results of corrosion test on SBF solution (simulated body fluid) show an increase in corrosion resistance along with the decreasing (smaller) size of steel ball diameter used.

Alkyl phosphate modified graphene oxide as friction and wear reduction additives in oil

Alkyl phosphate modified graphene oxide (GON-DDP) was successfully synthesized using dodecanol, ethanol amine and self-made graphene oxide (GO) as precursors. The structure and morphology of GON-DDP were characterized by FT-IR, XPS, TG/DSC, SEM and TEM. The characterization results indicate that long alkyl phosphate chains were successfully grafted on GO surface, which guaranteed the dispersibility of GON-DDP in hydroisomerization dewax base oil (VHVI8). Then the tribology properties of GON-DDP as friction reduction and anti-wear additive in VHVI8 were evaluated on four-ball machine and SRV test system. The results show that the friction coefficient and wear scar diameter were reduced by 22.7% and 30.3% compared with bare VHVI8 base oil. Moreover, the non-seizure load of VHVI8 was significantly raised by adding GON-DDP. Finally, the lubrication mechanism was proposed according to Raman analysis on the worn surfaces of steel balls.

Research on dual wavelength coaxial optical fiber sensor for detecting steel ball surface defects

The defects on a ground steel ball surface are very tiny and almost invisible; the existence of the defects will extremely influence the working stability of bearing system. To detect the surface quality on a steel ball effectively, dual wavelength coaxial optical fiber sensor technology is applied in this paper, and the defects are quantified as the characteristic parameters of displacement and roughness. The Matlab software was used to simulate the light intensity modulation characteristic ratio curve of displacement and roughness detection, the initial installation interval was determined as 0.8 mm between steel ball and the fiber sensor, and the wavelengths of light source were 1310 nm and 1550 nm. Experimental results showed that the coaxial optical fiber was suitable to detect the displacement, and dual wavelength to detect the roughness. The maximum errors of sensor displacement and roughness calibration experiment were 1.67% and 2.32% respectively in the measurement of steel ball with diameter 7.938 mm. The difference between the output curves was used to identify the defective balls from the good ones, which verifies the feasibility of the methods to detect the steel ball surface defects.