Lubrication Environment Research Articles

A new TiAlSiN coated tool and its machining performance evaluation for milling difficult-to-machining materials under MQL conditions

In this study, the Si and Al contents in a coating composition were improved, and a new TiAlSiN-coated tool was fabricated using high-power pulsed magnetron sputtering (HiPIMS). For comparison purposes, four types of coated tools, typically used in the market, were selected to mill 304 stainless steel in a minimum quantity lubrication environment. To evaluate the machining performance of the tools, the criteria of tool wear, workpiece surface roughness, and milling force were considered. The machining performance of the TiAlSiN-coated tools remained stable for all four working conditions, and it had the smallest compound milling force and tool wear in the experiment. The primary wear forms of the tools were coating peeling, oxidation wear, and adhesive wear. Under working conditions 1 and 2, due to the lower initial surface friction coefficient and thermal barrier effect, the workpiece surface roughness of the TiN-coated tools was the smallest, followed by that of the TiAlSiN. However, under inadequate working conditions, because of the good wear resistance of the TiAlSiN coating, it was not rapidly worn. This resulted in a lower average friction coefficient during processing and the workpiece surface exhibited the minimum surface roughness. A comparative analysis of the processing state of the five coatings under four groups of parameters indicated that the TiAlSiN coating had good processing stability, wear resistance, and a low surface friction value. The TiAlSiN-coated tools had better machining performance than the other four commercial-coated tools for 304 stainless steel machining, especially under working conditions 3 and 4.

Different Aspects of Machinability in Turning of AISI 304 Stainless Steel: A Sustainable Approach with MQL Technology

Machining of AISI 304 austenitic stainless steel is considered to be difficult due to its structural aspects and low thermal conductivity, which leads to increased temperatures during machining. To overcome the challenges of machining AISI 304 stainless steel, several cooling and lubricating techniques have been developed. The main objective of this experimental study is to evaluate the different turning conditions of AISI304 stainless steel under dry and minimum quantity lubrication (MQL) environment conditions. The machining experiments were conducted using a two-level full factorial design method and utilized a TiC-coated cutting tool. The tool-tip temperature, cutting force and surface roughness were analyzed regarding three cutting parameters namely, cutting speed, feed rate and cutting depth. Also, chip macro-morphology was investigated to define the interaction at the tool-chip-workpiece region. The cutting medium affects the surface roughness significantly (more than 100%) for all cutting parameter values. In some environmental cutting conditions, high cutting speed provides 10% lesser surface roughness than low cutting speed parameters. Also, the cutting force decreases by 20% in low feed rate machining conditions. However, the effect of this parameter disappeared for cutting forces in high feed rates and low cutting depth conditions in both MQL and dry environments. Cutting speed was observed as the most influential factor on surface roughness, followed by feed rate. The depth of cut was the main parameter that caused the temperature to increase in the dry machining environment.

Multi-Response Optimization of Milling Process of Hardened S50C Steel Using SVM-GA Based Method

This study aims to find the optimized parameters for surveying the milling process of S50C steel in a minimum quantity lubrication (MQL) environment using a support vector machine-genetic algorithm (SVM-GA). Based on the experimental matrix designed by the Taguchi method, surface roughness and cutting force data were collected corresponding to each experiment with changes in input parameters such as cutting speed, tooth feed rate, and axial depth of cut, along with changes in two parameters of the minimum lubrication system: flow rates and injection pressure. Through analysis by the SVR-NSGAII method, the study obtained the optimal parameters of cutting and lubricating conditions when prioritizing either surface roughness or focusing on the cutting force; however, the most comprehensive result is believed to be achieved by balancing these two factors. So, when striving for the neutral value of both output parameters, which are surface roughness (µm) and cutting force (N), the optimum parameters including injection pressure (MPa), flow rates (mL/h), cutting speed (m/min), feed rate (mm/tooth), and axial depth of cut (mm) are proposed.

Structure control of high-quality TiAlN Monolithic and TiAlN/TiAl multilayer coatings based on filtered cathodic vacuum arc technique

Coating techniques are used to improve the surface properties of materials. The filtered cathodic vacuum arc (FCVA) technology is an effective method to obtain high-quality dense coatings. Through FCVA technology, the contradiction between large thickness (over 10 μm) and compactness of TiAlN ceramic coatings was resolved. In this study, a monolayer TiAlN coating with a thickness of 17.13 μm, which possess a hardness of 34.31 GPa was obtained by the FCVA technology. The toughness of the coating was improved by the multilayer structure design which consists of TiAlN/TiAl. The best H/E and H3/E2 value of multilayer coating reached 2.38 times and 4.83 times higher than that of monolayer coating, and the hardness was only decreased by 15.46% at the same time. The highest critical load of adhesion strength for multilayer coatings reached 89.56 N, which is 1.98 times higher than the monolayer coating (44.24 N). For multilayer coating, the mass loss rate in anti-sand erosion test at high angle with the speed of 90 m/s is as low as 0.537 × 10−4 g/g. The erosion resistance per unit thickness of the multilayer coating reaches 1.9 times higher than that of the monolayer coating. At the same time, the multilayer coating has super wear resistance under oil lubrication environment. There is no obvious wear loss in the harsh reciprocal tribological test for 300 min with a normal load of 20 N and a reciprocating friction frequency of 4 Hz. The TiAlN/TiAl multilayer coating with large thickness and high density has excellent crack resistance and has application prospects in high load environments.

Friction and wear behavior of cemented carbide self-matching pairs under different water lubrication conditions

The friction and wear behavior of WC based cemented carbides ring-ring samples in different water environments were systematically tested. The average grain size of WC is 1.2 μm and the mass fraction of binder Co is 8%. The water environments include distilled fresh water, artificial seawater with NaCl mass content of 4%, and sediment water with SiO2 mass content of 0.6% and average particle size of 88 μm. The friction torque was measured for each friction pairs at different speeds and specific pressure loads. The surface morphology of the friction pairs before and after the test were observed by a scanning electron microscope, and the weight losses were also measured by a balance. The test results suggest that the friction coefficient of all the sample pairs decreases exponentially with the increase of load at proper revolution speed. In the range of 4–10 MPa specific pressure, the friction coefficient of the bearing during stable operation is between 0.01–0.02. The wear rate of the stationary ring is about 3 times that of the matching rotary ring, no matter in the environment of artificial seawater, distilled fresh water or sediment water lubrication medium. However, the wear rates of the samples in artificial seawater are higher than those of the two rings friction under the same speed and load conditions in the other two water environments. SiO2 particles in the sediment water has no effect on the bearings wear rate. The wear of cemented carbide self-matching pair bearings is mainly the peeling of WC particles caused by the alternating contact and friction force or plowing of WC abrasive particles. The corrosivity of artificial seawater can aggravate the peeling of WC particles. The results and conclusions of this study can provide a meaningful reference for the design of cemented carbide bearings utilized in water lubrication environment.

Effects on Machinability of Minimum Quantity Lubrication Strategy during Milling of ST52 Steel

This study focuses on milling under sustainable cutting conditions of ST52 steel, frequently used in the manufacturing industry. ST52 steel is a good candidate as a workpiece because it is inexpensive and readily available. To achieve sustainable conditions, the cutting zone minimum quantity lubrication technology was used during processing. The experiments used three cutting speeds (120-180-240 m min-1), three feed rates (0.12-0.18-0.24 mm rev-1), and a constant depth of cut (0.5 mm). Taguchi L9 orthogonal array was used to reduce repetitions. The response parameters are surface roughness, flank wear, and cutting temperature. As a result, when compared to the dry environment, the minimum quantity lubrication environment improved surface roughness by approximately 62.37%, flank wear by approximately 9.95%, and cutting temperature by approximately 13.82%. In addition, the most effective control factors on response parameters were determined by statistical analysis.

Ionogel Fiber‐Based Flexible Sensor for Friction Sensing

AbstractThe ability of flexible sensors to detect and recognize the perception of different mechanical stimuli is a prerequisite for meeting the challenges of flexible sensing in many applications. Although monitoring of frictional force and state is important and necessary, there is currently a shortage of highly sensitive sensors that can be used for frictional state sensing. This study demonstrates a high‐performance flexible sensor combining pyramidal micropatterns with ionogel nanofibers, which is capable of detecting both normal and tangential forces. The normal force is detected with a sensitivity of 1.145 kPa−1, a response time of less than 30 ms, and a hysteresis of 3.8%. More importantly, the sensor enables sensitive recognition of sliding speed, normal force load, tangential force, and oil lubrication environments with different viscosities in a reciprocating friction condition. It also enables sensitive recognition of the entire relative sliding process from zero slip to stick‐slip. The excellent frictional force and state recognition performances and long durability of 600 cycles at high‐frequency reciprocating friction indicate that the ionogel fiber‐based flexible sensor has a great potential application in friction sensing.

Performance investigations for sustainability assessment of Hastelloy C-276 under different machining environments

Hastelloy is categorized as difficult to cut superalloy widely used in aerospace, nuclear reactor components and chemical industry because of its magnificent strength and higher heat efficiency. Since, the machining of this material is quite difficult and hence suitable cooling systems are required to achieve sustainable manufacturing goals. The present investigation has been focused on the machining performance and sustainability assessment of turning Hastelloy C-276 in dry, flood and minimum quantity lubrication (MQL) environments. Taguchi L-9 array has been utilized to conduct and record the experimental output along with TOPSIS approach to evaluate the sustainability. The output responses viz. cutting forces, surface roughness, cutting temperature, energy consumption and carbon emission have been recorded at various levels of input variables. The experimental results revealed that MQL has minimized the cutting forces, surface roughness and temperature by margin of 20–38%. Likewise, energy expenditure and carbon emission was declined by 9–27% respectively compared to other conditions. Sustainability analysis explored best performance index during equal weightage criteria at 125 m/min, 0.246 and 0.8 mm doc under MQL. However, implementing assigned weightage system evaluated best condition for dry machining as 88 m/min and 0.246 mm/rev having same doc. SEM analysis of insert reported mainly abrasion and adhesion type of tool wear at all parametric range and machining conditions.

Tribofilm formation mechanism and friction behavior of polycrystalline diamond compact after cobalt leaching added molybdenum disulfide nanoparticles in different base oils

To investigate the friction and wear properties of polycrystalline diamond compact after cobalt leaching(PDCACL)and the formation mechanism of lubricating oil film under different base oil lubrication conditions, AFM, SEM, EDS and XPS were used to analysis and discuss the friction behavior, microstructure and friction film formation process of PDCACL after adding nano molybdenum disulfide in different base oils. The results showed that there are differences in the speed and thickness of the friction protective film formed by PDCACL under different kinds of base oil lubrication environment. The physical and chemical properties of base oil are the key factors affecting the wear mechanism of PDCACL and the formation of friction film.

Evaluation of tribological behavior of silicon carbide and silicon nitride ceramics under different conditions

AbstractA comparative analysis of the tribological behavior of commercially available sintered silicon carbide (SiC) and three different types of silicon nitride (Si3N4) ceramics have been carried out using the ball‐on‐disk method in dry and lubrication (deionized [DI] water and ethanol) environment. Scanning electron microscopy (SEM) was used to understand the morphology and chemical composition of the tribo‐surfaces. Sintered SiC (Hexoloy‐SA) had the highest friction coefficient during dry sliding with an average of ∼0.34. Deionized water showed a minor improvement in friction (∼0.27) while ethanol reduced the friction greatly to ∼0.18 compared to dry sliding. During dry sliding, the presence of an abrasive third body was responsible for the high wear rates (WRs) in these compositions. Hexoloy‐SA showed a lower WR during ethanol and DI water lubrication due to the formation of stable tribofilms as well as higher hardness which resisted the formation of third bodies. In comparison, Si3N4 samples showed a lower WR in DI water and ethanol. The samples also showed composition‐dependent behavior which indicates that grain structure and grain boundary chemistry are playing a vital role in the tribological process.

Tool Life of Uncoated and Coated Inserts during Turning of Ti6Al4V-ELI under Dry and Minimum Quantity Lubrication Environments

This paper mainly deals with the tool wear characteristics of uncoated cemented carbide insert and PVD AlTiN, PVD TiAlN coated carbide inserts during turning of Ti6Al4V-ELI (Extra Low Interstitial). To satisfy the sustainability conditions, the experiments have been conducted under dry and minimum quantity lubrication (MQL) environment. To enhance the effectiveness of MQL, palm oil has been used as the cutting fluid. The same machining parameters are employed for all the cutting tool inserts in dry and MQL environments to understand the machining characteristics better. It was found that cutting speed greatly influences average flank wear. Tool life of PVD TiAlN coated tool is more in both MQL, and dry environments as compared to uncoated cemented carbide insert and PVD AlTiN coated insert. Using palm oil under the MQL environment has produced better results while turning by PVD TiAlN insert. The characteristics like good cooling and lubrication provided significantly less average flank wear during machining of Ti6Al4V-ELI under the MQLenvironment.

Environmental sustainability during machining of hardened steel using nanofluid: A case study

The positive effects of nanofluid-assisted minimum quantity lubrication include improved performance during machining and environmental sustainability. In the present study two cutting parameters levels such as feed rate of 0.05 (mm/rev)- depth of cut of 0.1(mm)-cutting speed of 80(m/min) and feed rate of 0.15(mm/rev)-depth of cut of 0.3(mm)-cutting speed of 200(m/min) has been used in the hard turning of D2 steel. It was determined that the 0.3% ZrO2 wt% observed to be improved machinability as compared to dry and Minimum Quantity Lubrication (MQL) environment. Finally, the sustainability assessment through the Pugh Matrix Assessment (PMA) presented the potential of nanofluid-MQL for improvement of machinability of hardened D2 steel for cleaner production.

Research on the design and bearing characteristics of shipborne spiral elevator in specific small space

This work aims at the problem that the temperature rise, gluing or wear of the thread sliding friction pair under fast and heavy load make it difficult to estimate the service life of the equipment. Based on the numerical simulation method and the heat balance theory of the screw friction pair, the bearing characteristics of a self-designed shipborne multi-section free-telescopic screw elevator are studied. The results show that the stress of the thread tooth is mainly concentrated in the root area of the thread tooth, and the load of the thread is mainly concentrated in the first three threads of the meshing thread. When the friction coefficient is more than 0.3, the friction temperature rise will lead to gluing failure. Therefore, a good lubrication environment can effectively reduce the friction coefficient of the thread and reduce the screw contact surface gluing failure caused by the friction torque work heating.

Influence of rotation speed on abrasive wear behavior of the UHMWPE in lubrication environment

AbstractTo better understand the damage failure mechanism of ultra‐high molecular weight polyethylene (UHMWPE) in engineering application environments, a study was conducted to explore the effect of rotation speed on its abrasive wear performance in lubricant media containing abrasive particles, especially in comparison to the water. The wear mechanism was analyzed by friction coefficient and wear behavior. The results show that UHMWPE has excellent tribological properties in the water and is seriously worn in the abrasive environment. Under the condition of abrasive wear, there exists a critical rotation speed (360 r/min) leading to a shift in the wear mechanism of UHMWPE and obtaining the lowest wear rate of about 8.49 × 10−6 mm3/N•m. At below critical rotation speed, three‐body abrasive wear and adhesive wear mainly occur in UHMWPE; And at above critical rotation speed, the wear mechanism is mainly the plowing effect of particles on the material, and the furrow width can reach 40 μm. It is believed that this study can help to improve the understanding of the wear mechanism of UHMWPE, which can support the enhancement modification of the material and the application in complex environment.

Performance Characteristics of Spur Gears Hobbed under MQL, Flood Lubrication, and Dry Environments

This paper presents the influence of three lubrication environments, namely hobbing with minimum quantity lubrication (HWMQL), hobbing with flood lubrication (HWFL), and hobbing without any lubrication (HWAL), on the wear characteristics, microhardness, functional performance parameters, generation of noise and vibrations, flank surface roughness, and microgeometry deviation parameters of spur gears. Convective heat transfer coefficients in HWMQL and HWFL are evaluated to study the cooling mechanism involved and their heat dissipation capabilities during spur gear manufacturing. It is found that HWMQL-manufactured spur gears exhibited higher microhardness and smaller values of microgeometry deviations, flank surface roughness, functional performance parameters, wear rate, wear volume, and noise and vibrations than the spur gears manufactured by HWFL and HWAL. HWMQL facilitated a significantly higher convective heat transfer coefficient than HWFL, indicating its superior hobbing performance. An examination of the worn flank surfaces of HWMQL-manufactured gears revealed a wear track that resulted in less abrasive wear, wear debris, and subsurface damage, whereas the worn flank surfaces of HWFL-manufactured gears showed deep grooves, feed marks, and surface defects. This study proves that HWMQL is capable of manufacturing gears with better accuracy, enhanced wear resistance, smoother and quieter operational performance, and longer service life due to its better cooling and lubrication action. The results of this study will be very helpful for the manufacturers and users of spur gears.

High-Efficiency Machining of Titanium Alloy Using Combined Machining Method of Driven Rotary Tool and Hale Machining

Titanium alloys are widely used as aerospace materials, especially for turbine blades, due to their excellent mechanical properties. In the high-efficiency machining of titanium alloy turbine blades, the feed rate for ball-end milling is limited to 1000 mm/min due to the low thermal conductivity and chemical reactivity of the titanium alloy. These characteristics result in tool damage and an increase in the cutting temperature, significantly reducing the machined surface accuracy. A new processing method is thus needed for achieving a high accuracy and high efficiency in titanium alloy machining. It has been reported that driven rotary machining of hardened steel improves the machined surface and increases the processing efficiency, suggesting that high-efficiency machining can be realized by employing hale machining with a rotary tool. In this study, hale machining was performed using a driven rotary tool and the effects of different cutting conditions and cutting environment on the machining characteristics were investigated. The results showed that the tool life was longest at a feed rate of 9000 mm/min among the three feed conditions because the number of times of adhesion and detachment decreased with the decreasing friction distance of the cutting edge. Furthermore, it was clarified that adhesion formation at the cutting edge was suppressed by lubrication with an oil mist in a minimum quantity lubrication environment. This lubrication effect reduced the tool damage and adherence at the cutting edge, significantly extending the tool life and improving the machined surface quality compared to the results obtained in a wet environment.

Wear Behavior of Bronze vs. 100Cr6 Friction Pairs under Different Lubrication Conditions for Bearing Applications

Damage due to a shortage or excess of or the pollution of lubricating oil is often cited as one of the most significant issues confronted by the rolling mill sectors. Lubrication can be provided by either central lubrication systems or individual lubrication systems. In this study, the wear characteristics of the mono-block rolling plain bearing material that is utilized in wire rod rolling mills were evaluated under conditions where the lubricating oil medium included either 2.5% of scale, 5% of scale, or no scale at all. In this experimental study, a unique ball-on-flat experimental setup similar to the one used in the ASTM G133-05 standards was used. Bronze was used as the bearing material and 100Cr6 roller-bearing steel was used as a steel ball of 6 mm in diameter. The experiments were carried out at room temperature, at three different sliding speeds of 5 mm/s, 10 mm/s, and 15 mm/s, and with three different loads of 10 N, 20 N, and 30 N. The wear mechanisms were analyzed visually and elementally using Scanning Electron Microscope (SEM) and Energy-Dispersive X-ray Spectroscopy (EDX) methods. An Analysis of Variance (ANOVA) and the Response Surface Method (RSM) were used to analyze the test results, such as volumetric material loss, the coefficient of friction, and the surface profile. In this study, which was carried out in a lubricant environment containing solid particles, the most effective parameter was the environmental parameter. The increase in the number of solid particles caused an increase in volume loss and friction coefficient.

Understanding the efficiency of roll lubrication when rolling AD33 aluminium alloy bands in industrial twin mill 175Ч300

This paper describes the results of a study that looked at the effect of contact conditions (including the use of industrial oil I40 (5%) for roll lubrication) on the deformation performance and power draw of a twin cold mill 175×300 operated by the machine building site in Dong Nai, Vietnam, when rolling 0.55 mm thick bands made of aluminium alloy AD33. The initial band size is 0.7×100×2,000 mm. The authors considered reological properties of the aluminium alloy, as well as the roll lubrication environment, to come up with a rational rolling process designed for 0.55×100 mm bands made from 0.7×100×2,000 mm rolled steel. Due to the use of industrial oil I40 (5%) in the mill 175×300, the number of passes could be reduced from three to two. The use of industrial oil I40 (5%) in the twin mill 175×300 ensured the specified precision and helped reduce the loads. Compared with dry rolling, due to the use of industrial oil I40 (5%), the rolling force could be lowered by 6 kN (8.3%) in the first pass and the power draw – by 0.025 kW (3.34%). At the same time, the second pass saved 2.96 kN (5.24%) of rolling force and 0,017 kW (3.95%) of power while ensuring the preset band thickness at the mill exit. Compared with dry rolling, when using I40 oil, the rolling force distribution efficiency along the band length rises by 22.7% in the first pass and by 14.64% in the second pass. When using I40 oil (5%), the strain distribution u nevenness along the band length drops by 39.15% — from 2.35 to 1.43% in the first pass and by 70.08% — from 3.81 to 1.14% in the second pass. When using I40 oil (5%), the thickness distribution along the length of aluminium band at the mill exit is more even than when the rolls are dry or use water. It also results in a minimized longitudinal thickness variation δh – i.e. 0.01 mm. These findings helped develop a rational rolling process for AD33 aluminium alloy bands that relies on the use of industrial oil I40 (5%) to lubricate the rolls of an industrial twin mill, while cutting the loads and saving power.

Understanding the lubrication regime phenomenon and its influence on tribological characteristics of additively manufactured 316 Steel under novel lubrication environment

The degree of surface separation is generally used to determine the lubrication regimes. The smooth functioning of components are possible by providing the lubrication at intermediate zone, which reduces the wear and prevents severe stresses or bearing arrests. This work is also focus on lubrication regime phenomena and its influence on tribological characteristics of additively manufactured 316 steel under novel lubrication environment. The tribology tests were performed on ball-on flat machine under dry, minimum quantity lubrication (MQL), cryogenic and hybrid cryo+MQL conditions. The 100Cr6 ball has been used against additively manufactured 316 steel and the theoretical exploration of lubrication regimes has been discussed along with other tribological characteristics such as wear rate, surface roughness and coefficient of friction etc. The outcome demonstrated that the hybrid cryo+MQL is helpful in providing the good lubrication film and consequently improves the tribological properties.

Multi-response optimization in turning of EN-24 steel under MQL

Cutting fluids used in manufacturing industry have environmental and economic drawbacks. In order to reduce the negative effects associated with cutting the fluids, it is now becoming indispensable to move towards more sustainable techniques. In this research work, the turning of EN-24 steel under minimum quantity lubrication (MQL) environment have been done. The study has been completed three phases. The first phase deals with planning of experiments based on Box-Behnken design. The influence of input process parameters i.e., cutting speed, feed rate, depth of cut and MQL flow rate have been investigated on output parameters i.e., surface roughness, tool wear, cutting temperature and cutting force. The desirability approach strategy has been used for multi-response optimizationof input parameters in the second phase.The third step deals with analysis of results using SEM, 3D surface graphs and main effect graphs. The confirmation experiments have been carried out to verify the developed model. Experimental results revealed that, the turning performance under high MQL flow rate has been found to be the most effective parameter on mean surface roughness, cutting temperature, tool wear and cutting force.