Wear Life Research Articles

Digitized Seedbed Soil Quality Assessment from Worn and Edge Hardened Cultivator Sweeps

Tillage tools for seedbed soil management are often subjected to low stress abrasion wear, which could negatively affect seedbed quality and crop productivity. Limited studies exist that quantify the effects of worn tillage tools on seedbed quality and crop yield. This research investigated the influence of tillage tool wear on seedbed preparation by evaluating the effect of cultivator sweep wear on soil tilth utilizing a light detection and ranging (LiDAR) sensor. The framework consists of a seedbed tillage field experiment using a Completely Randomized Design (CRD) experiment in six replicates of two-tillage treatments (new and worn cultivator sweeps). After seedbed tillage, loosely tilled soil aggregates were removed to expose the seedbed soil profile, and then seedbed roughness statistical measures were estimated from LiDAR-scanned seedbed soil surface. Three statistical analyses (Analysis of Variance (ANOVA), Kolmogorov–Smirnov (KS), and Earth Mover’s Distance (EMD)) were compared to quantitatively evaluate the soil roughness estimated from the LiDAR seedbed surface data. Seedbed prepared by new and worn cultivator sweeps showed significant differences (p < 0.05) in soil roughness variables of standard deviation, coefficient of variation, and kurtosis. Data analysis from the ANOVA and KS methods revealed that LiDAR-extracted soil roughness patterns were statistically influenced by tillage treatment. EMD analysis detected noticeable disparities between the tillage treatments and new versus worn cultivator sweeps. This study concludes that tillage tool wear substantively affects seedbed quality, as evidenced by LiDAR soil profile estimated attributes of soil roughness and three statistical methods (ANOVA, KS, and EMD). Our study supports the adoption of LiDAR technology for seedbed management, highlighting its applicability to evaluate seedbed quality that accounts for the wear life cycle of cultivator sweeps.

Influence of tungsten carbide spray treatment on anti-wear performance of Francis turbine runner blades surface

Based on the velocity similarity theory, a test system for sediment wear flow around Francis turbine runner blades was established. The sediment wear test was carried out on the surface of Francis turbine runner blades with severe sediment wear before and after tungsten carbide spraying. The wear rate prediction model was established, and the effect of tungsten carbide spraying on the wear resistance of runner blades was analyzed. The results show that the serious wear position of Francis turbine runner blade by sediment appears in the head and tail, and the greater the load, the more serious the wear; after tungsten carbide spraying treatment, the sediment wear of runner blades is reduced by more than 90%, and the wear life is greatly improved. The sprayed tungsten carbide coating treatment is effective in reducing the effects of sediment wear.

Wear of Wave Energy Converters Mooring Lines Belts

Abstract Using a belt as a replacement for a rope on a rotary power take-offs (PTOs) system has become more common for wave energy converters, improving cyclic bend over sheave performance with a smaller bending thickness for belts. However, the service life predictions of PTOs are a major concern in design, because belt performance under harsh underwater environments is largely less studied. In this work, the effect of fleet and twist angles on wear life is being investigated both experimentally and numerically. Two three-dimensional equivalent static finite element models are constructed to evaluate the complex stress state of polyurethane-steel belts around steel drums. The first is to capture the response of the experimental investigation performed on the wear life, and the second to predict the wear life of an existing functional PTO. The results show a significant effect for fleet and twist angles on stress concentrations and estimated service life.

Investigation of tribology and life prediction of polymer coatings on 7N21 aluminum alloy under dry sliding wear

To improve the tribological properties of the 7N21 aluminum alloy under dry sliding wear conditions, three E44-PI-PAI composite coatings filled with varying contents of MoS2, h-BN and VN were designed. The mechanical and tribological performances of these coatings were evaluated using scratch experiments, nanoindentation, and sliding wear experiments. After identifying the optimal coating, the engineering constants of the coating were determined using tensile experiments. Finally, a simulation analysis of the reciprocating wear life was performed using ABAQUS and a custom-developed UMESHMOTION subroutine. The results indicate that the optimal ratio of MoS2, h-BN and VN in the designed polymer coating is 4:3:4. The coefficient of friction (CoF) and wear rate of the optimal coating are 0.189 and 0.444×10−14 m3/Nm, representing a 67 % reduction in CoF compared to the 7N21 aluminum alloy. The L2 coating demonstrates excellent compatibility, featuring a surface roughness (Ra) of 0.630 μm, a uniform thickness of 10±2 μm, an optimal bonding strength at level 0, and a nanohardness of 0.391 GPa, meeting the requirements for engine bearings. The maximum deviation between the simulated wear life prediction and experimental results is only 8.11 %.

Investigation of End-of-Life Chrome-Magnesia Refractories Using X-Ray Computed Tomography

The lifespan of refractory linings is a major industrial concern for safety, on-line availability, and financial reasons. In copper smelting, batchwise operating matte converters are the furnaces that pose the greatest challenge when it comes to refractory wear and lining life. In this work, the structure and morphology of used magnesia–chrome bricks were studied using X-ray computed tomography and mineralogical techniques. The bricks were taken from various locations of an end-of-life brick lining of an industrial Peirce–Smith converter, after a normal campaign at Boliden Harjavalta smelter (Finland). The results show that it is possible to visualize in 3D, e.g., porosity, metal-containing phases, and refractory magnesia in the used bricks. Different digital images, such as cross-sections and average volume fractions, were used as a non-destructive method to characterize the bricks’ internal structure. The metal/matte infiltration in the open porosity was found to differ based on the location in the converter, with some bricks having no metal/matte infiltration and the tuyere line showing metal/matte infiltration at a depth of about 100 mm from the hot face.

Surface integrity and high-cycle fatigue life of direct laser metal deposited AISI 431 alloys modified by plasticity ball burnishing

Laser metal deposition (LMD) as an additive manufacturing (AM) is widely used to repair and extend wear and fatigue life of the critical components. This paper has investigated the application of ball burnishing (BB) to improve surface integrity and high-cycle fatigue resistance of LMDed AISI 431 alloys. Results showed that the BB treated samples exhibited significant surface finish improvement by lowering roughness by 91 %. Microhardness increased from 490 to 530 HV0.1, an increase by 10 % with a modified depth of 400 µm from the top surface. XRD results showed a peak shift and increase in FWHM by up to 17 %. This had been corroborated by EBSD exhibiting a 20 % increase in dislocation density and 24 % increase in localised misorientation within microstructure. As a result, the overall high cycle fatigue strength of the burnished sample increased by 50 %, and the cracks initiated from sub-surface level defects at a depth of 350 μm below the top surface, delaying the crack propagation and fracture failure. The findings clearly highlight that the burnishing treatment can be a plausible approach in improving the dynamic fatigue resistance and the overall service life of LMDed AISI 431 steel alloys components in engineering applications.

Experimental and numerical investigation of the TBM disc cutter wear using a new tunnel boring machine laboratory simulator

One of the essential and practical issues on TBM performance is the wear during the excavation process of abrasive and resistant rock. The wear of the disc cutter, which is caused by the gradual and uniform reduction of the diameter of the disc cutter, is caused by the rock-machine interaction during excavation, and various factors can intensify this phenomenon and reduce the wear life of the disc cutter. To obtain a proper view of the relationship between the operating parameters of the excavation machine and the disc cutter wear, a new laboratory device has been designed and built in the mechanized excavation laboratory of the Sahand University of Technology. By using this device, the amount of wear of cutting tools in excavation machines can be obtained against rough rock samples, and from the results, the amount of wear of cutting tools of excavation machines can be minimized so that the efficiency of the excavation machine can be increased. In the current research, the laboratory wear results obtained from this device have been compared with those obtained from the numerical modelling of the same device in PFC3D discrete element software, both for the cutting blades and the sample itself. This research showed that in the first abrasion stage of the sample, the difference in the abrasion weight of the experimental study and numerical modelling for the samples varies from 0.91 to 0.768 g, and the average is 0.202 g. Also, the difference between the abrasion percentage of laboratory study and numerical simulation for the samples varies from 6 to 14 %, and the average is 10 %. In step 2 of abrasion, the difference in the abrasion weight of the experimental study and numerical modelling for the samples varies from 0.118 to 0.556 g, and the average is 0.278 g. Also, the difference in the abrasion percentage of laboratory study and numerical simulation for the samples varies from 7 to 14 %, and the average is 11 %. The results of the new tunnel boring machine laboratory simulator revealed insights into wear behavior during different stages of excavation.

Wear prediction of high performance rolling bearing based on 1D-CNN-LSTM hybrid neural network under deep learning

The finished precision rolling bearings after processing are required to pass the life test before they can be put into the market. The life testing takes a lot of time and expense. Aiming to solve the problem of time and expense, the 1D-CNN and 1D-CNN-LSTM hybrid neural networks are used for deep learning based on the existing rolling bearing life big data results (a total of 791152 date). Taking the wear of bearing as the target, the life prediction of bearing is carried out by using Python. The results show that: (1) 1D-CNN-LSTM algorithm and "all parameters” are selected as the best prediction options. (2) "XYZ direction displacement” and "all parameters” have the best fitting effect on the predicted wear value, and the MAPE is 4.18877, 1.2102, 2.68903 and 1.19981, respectively. The 1D-CNN-LSTM algorithm is slightly better than the 1D-CNN algorithm. (3) Using 1D-CNN-LSTM algorithm and "all parameters” to predict the bearing wear life will obtain good results. Compared with the highest 1D-CNN and "Four Bearing Temperatures” parameters, it is reduced by 14.7 times. (4) The prediction process and results provide a wear prediction method for relevant bearing enterprises in the experimental running-in stage. It can also provide reliable research ideas for subsequent related enterprises and scholars.

Experimental investigations and finite element simulation for predicting wear life of overrunning clutches

An overrunning clutch, generally known as a freewheel clutch, is a direction dependent torque transmitting device that works on the principle of wedge friction. The overrunning wear characteristics of freewheels are studied using pin-on-disc tribometry. The wear experiments for freewheels are performed at accelerated loads to promote wear in a short period. The overrunning wear life of the clutch under operating conditions is predicted using an appropriate load-life relationship. A finite element-based Archard’s wear model is implemented as a numerical strategy to evaluate the wear profile. The maximum local wear for various loads is computed using experimentally obtained wear and friction coefficients. The numerical simulation is performed with an adaptive mesh technique utilizing incremental nodal displacements to predict surface wear. The experimental and numerical results are compared in terms of wear characteristics. The numerical wear results are almost 11% higher than the experimental results. The wear life of an overrunning clutch is predicted in terms of overrunning speed based on the wear amount.

Theoretical Evaluation of Lubrication Performance of Thrust-Type Foil Bearings in Liquid Nitrogen

The development of reusable liquid rocket turbopumps has gradually highlighted the disadvantages of rolling bearings, particularly the contradiction between long service life and high rotational speed. It is critical to explore a feasible bearing scheme offering a long wear life and high stability to replace the existing rolling bearings. In this study, liquid nitrogen is adopted to simulate the ultra-low temperature environment of liquid rocket turbopumps, and theoretical evaluations of the lubrication performance of thrust-type foil bearings in liquid nitrogen are conducted. A link-spring model for the bump foil structure and a thin-plate finite element model for the top foil structure are established. The static and dynamic characteristics of the bearings are analyzed using methods including the finite difference method, the Newton–Raphson iteration method, and the finite element method. Detailed analysis includes the effects of factors such as rotational speed, fluid film thickness, thrust disk tilt angle, and the friction coefficient of the bump foil interface on the static and dynamic characteristics of thrust-type foil bearings. The research results indicate that thrust-type foil bearings have a good load-carrying capacity and low frictional power consumption. The adaptive deformation of the foil structure increases the fluid film thickness, preventing dry friction due to direct contact between the rotor journal and the bearing surface. When faced with thrust disk tilt, the direct translational stiffness and damping coefficient of the bearing do not undergo significant changes, ensuring system stability. Based on the results of this study, the exceptional performance characteristics of thrust-type foil bearings make them a promising alternative to rolling bearings for the development of reusable liquid rocket turbopumps.

Effect of tooth surface wear on dynamic characteristics of spur gear transmission system

The meshing stiffness and system dynamic characteristics caused by gear wear fault are studied. Firstly, potential energy method was used to model and solve the meshing stiffness of gears and the effect of wear on the meshing stiffness and static transfer error was analyzed. A 6-dof spur gear dynamics model was established considering various nonlinear factors, and the dynamic responses of the spur gear system under various wear degrees were analyzed by using time domain, spectrum, phase plane, and Poincare mapping. Finally, the visual test platform of the gear box is built, and the wear condition and dynamic response of the gear box under different wear cycles are analyzed. Results show that the meshing stiffness of gear decreases due to wear, and the meshing stiffness of double tooth decreases more than that of single tooth. In addition, the static transmission errors caused by wear changes periodically with meshing frequency. Wear causes the vibration response of gear system to become complex gradually, and the nonlinear of the system is enhanced, which changes from single period motion to quasi period motion. Results can provide theoretical support for gear wear reduction, life extension, vibration reduction, and noise reduction and lubrication improvement.

Regulating the severe running-in wear of polymer composites by a dual-pin-on-disk (DPOD) multicomponent approach

Polymer composites are increasingly used as frictional components due to their self-lubricating properties. However, they tend to exhibit severe wear during the running-in stage, thus significantly impairing their service life. In the present work, a dual-pin-on-disk (DPOD) method is developed in order to reduce the running-in wear of a polytetrafluoroethylene/alumina (PTFE/Al2O3) composite when sliding against GCr15 bearing steel by introducing an assistant polymer component during the running-in stage. The results show that the running-in wear rate of the main polymer pin is reduced by up to 77.26 %. This is because the assistant pin causes excess wear debris to be released into the wear track and provides a higher shear force, thereby promoting the tribological chemical reactions and facilitating the generation of tribofilms on the worn surfaces. In addition, the processed polymer achieves a wear rate similar to that of the conventional single pin condition (∼3 × 10−7mm3/Nm) in the subsequent steady-state stage. The results of the present work are expected to increase significantly the wear life span and application prospects of the polymer composites.

Effect of deposition pressure on friction and wear properties of BWS2 composite coatings

This study investigated the impact of deposition pressure on the microstructure and tribological properties of B/WS2 composite coatings deposited via unbalanced magnetron sputtering. Deposition pressures of 0.6 Pa, 0.8 Pa, 1.0 Pa, 1.2 Pa, and 1.4 Pa were used during the deposition process. The microstructure and mechanical properties of the B/WS2 composite coatings were characterized, and friction and wear experiments were conducted. The study found that the microhardness of the B/WS2 composite coatings decreased as the deposition pressure increased. The highest hardness of the coating, reaching 8.1GPa, was observed at a deposition pressure of 0.6 Pa. This was due to the formation of Tungsten tetraborate (WB4) during the deposition process, which had a high hardness and improved the mechanical properties of the coating. The wear life of the B/WS2 composite coatings was at its best, reaching 9.9 × 104 cycles, and the friction coefficient was at its lowest when the deposition pressure was 1.2 Pa. Selecting an appropriate deposition pressure can improve the tribological properties of B/WS2 composite coatings. Doping Boron can improve the hardness and wear resistance of the composite coatings. Abrasive wear and spalling are the two main wear forms of B/WS2 composite coatings.

Study on the Friction Characteristics and Fatigue Life of Carbonitriding-Treated Needle Bearings

Being a key component of the transmission system, the needle bearing’s performance and service life affects the overall service life of mechanical equipment. This study takes needle bearings composed of AISI 52100 steel as the research object and studies the effect of carbonitriding surface strengthening treatment on the bearing friction, wear, and fatigue life. The carbon and nitrogen co-infiltration surface-strengthening method was employed to prepare cylindrical and disc samples. The surface hardness, residual austenite content, microscopic morphology and organization composition, coefficient of friction, and wear scar were studied to analyze the effect on the wear performance of the material. The bearing fatigue wear comparison test was conducted on a test bench to compare the actual fatigue life and surface damage of the needle bearing through conventional martensitic quenching heat treatment and carbonitriding treatment. The results demonstrate that the carbonitriding strengthening method enhances the toughness of the material while improving its surface hardness. It also improves the wear resistance of the needle roller bearings, and the fatigue life of the bearings is significantly improved. In conclusion, carbon and nitrogen co-infiltration treatment is a strengthening method that effectively extends the service life of needle roller bearings, indicating its high practical value.

Cloud maps highlighting dynamic characteristics of surface signal to improve time-varying wear evaluation accuracy

This paper proposes a high accuracy time-varying wear evolution method with cloud maps highlighting dynamic characteristics of surface signal. Firstly, the cloud map method is established by arrangement of measured data, thus time-varying wear evolution process is visualized on a series of plane figures for preliminary qualitative analysis. Then, high accuracy recognition of time-varying wear states is realized by cloud map shape parameters, including kurtosis and 1-D kernel density function highlighting distribution information of surface signal. The relative recognition degree by cloud map shape parameters are higher than those of friction coefficient, Root-Mean-Square (RMS) deviation and fractal dimension. Finally, high accuracy time-varying wear life prediction is realized by cloud map size growing speed highlighting waviness information of surface signal. The relative prediction error is reduced from more than 20% to less than 10% compared with friction coefficient and roughness.

Effect of Cryogenic Heat Treatment on Multiple Tempered D-2 Tool Steel

The present day scenario in the manufacturing sector demands high productivity and the life of cutting tools plays a major role in increasing productivity. The freezing of metals has been acknowledged, for many decades, as an effective method for increasing" wear life" and decreasing residual stress in tool steels. Wear test using pin-on-disc machine was used to investigate the effect of multiple tempering after cryogenic treatment of D-2 tool steel. Conventional quenching (1010◦C) and tempering (515◦C) treatments were given along with intermediate cryogenic treatment (−196◦C). Specimens were subjected to wear tests on pin-on-disc machine in dry sliding condition for sliding distance of 6000 m at 6 kg load and for sliding speed of 3.0 m/s. Hardness data, microstructures, wear loss and Microstructure analys is analysis of worn surface throw light on the underlying metallurgical mechanism responsible in improving wear resistance property of the D-2 tool steel

Development and performance of additively manufactured Tungsten carbide tool insert: An application of additive manufacturing towards flexible and customized machining

Carbide tool manufacturing is proposed by Additive Manufacturing to introduce flexibility and customization in machining industries. Development and performance of the additively manufactured (AM) tool is reported. Crack-free deposition of 88 wt%WC was obtained at 800 °C substrate-preheat temperature. An insert was dimensioned and progressive turning of Aluminium 6061-T6 alloy was performed upto 65 min at various cutting speeds. Cutting force, chip-reduction-coefficient, shear angle, built-up-edge, flank wear, crater wear and tool life of AM tool were analysed. The flank wear of AM tool was observed as 0.219 and 0.314 µm respectively at cutting speeds of 120 and 140 m/min after 65 min of machining. The cutting performance of the AM tool was then compared with that of K20 conventional cutting tool insert.

Force and wear prediction model of disc cutter under compression shear failure mode based on dense core–cavity expansion theory (U-713)

Calculating disc cutter wear and predicting wear life are long-standing issues affecting the efficiency and cost of tunnel boring machines (TBMs). During the TBM excavation process, the wear of the disc cutter is a comprehensive outcome of the interaction between the tool and rock. Studying the mechanisms of tool rock breaking and wear can assist in developing a more precise model for predicting cutter wear. Therefore, based on the rock-breaking and wear mechanisms of a cutter, this study developed a model for predicting the cutter wear rate and life. The model is based on the theory of dense core–cavity expansion combined with the motion state of a cutter. First, the TBM excavation process and rock-breaking mechanism of a cutter were analyzed in detail. A cutting force model under the compression shear failure mode based on the dense core–cavity expansion theory was established. Based on the force model, a prediction model for the wear rate and life of the disc cutter was established, considering the working characteristics and wear mechanism. Furthermore, the impact of penetration on the prediction model was investigated. In addition, to demonstrate the practicality of the method, this study conducted a comprehensive examination using engineering examples. The results showed that the average difference in the cutter average wear rate using the developed model was less than 3% compared with the actual engineering result. In addition, the average difference in the wear life rate was less than 5%. Finally, the developed prediction method was compared with other models. The wear rate fitting accuracy was improved by 4.91–10.85% and the wear life fitting accuracy was improved by 5.11–12.19% by the developed method. This improvement confirms the reasonableness and reliability of the method. This method can estimate the wear rate and lifespan of a cutter more accurately and reliably than other methods, providing a practical tool to TBM engineers to make informed decisions and optimize tool replacement programs.

Research on rock breaking behaviors of different TBM hobs under grooving condition produced by water jet

The water-jet-assisted method is very promising to improve the cutting performance of the TBM hob. The current researches are mainly focused on flat-blade hob (FB hob), but the researches on the rock breaking behaviors of spherical-tooth hob (ST hob) and pyramidal-tooth hob (PT hob) under grooving condition produced with water jet are very limited. To investigate the rock breaking behaviors of FB, ST, and PT hobs under the grooving condition, the penetration experiments and simulations of the three types of hobs are conducted. Then the penetration process, penetration force, and penetration efficiency of three types of hobs are compared and discussed. The results denote that the elastic deformation of the rock first is presented, then a dense nucleus is produced, and finally, a huge rock chip is formed with the growth of the penetration depth, regardless of the hob types. During this penetration process, the penetration force first rises steadily and then reaches its peak value, and finally drops and fluctuates. The increasing speed of penetration force for the FB hob is larger than that of the ST and PT hob during the increasing phase of the penetration force. Meanwhile, the peak penetration force and penetration difficulty coefficient of the FB hob are also larger compared with that of the ST and PT for the same cutting width. To effectively use the cutting groove to promote macro crack propagation and break rock, the cutting width should be controlled within the critical cutting width, 40, 40, and 30 mm, respectively for the FB, ST, and PT hob. At such critical cutting width, namely the optimal cutting width, the highest penetration efficiency can also be achieved. Besides, as the cutting width ranges within the optimal cutting width, the three types of hobs' breaking efficiency could be evidently enhanced with the assistance of the cutting groove. The ST hob presents better adaptability in breaking rock under the grooving condition simulating water-jet-assisted method compared with the FB and PT hob, considering the hob's breaking force, breaking efficiency and wear life.

Superior interface adhesion and protective mechanism of room-temperature-curable polymer composite coating on engineering substrates with lower roughness

In view of the technology bottleneck of the adhesion failure of traditional functional protective coatings on the smoother surface of precise parts served in the marine atmosphere, a room-temperature-curable fluoropolymer/polyurethane (denoted as RFP) polymer composite coating of 20–30 μm is prepared on the metal substrates. Static pull-off and dynamic friction test methods are used to evaluate the interface adhesion of the coating. The coating shows superior adhesive strength of 18–24 MPa on a variety of metal substrates with a wide range of surface roughness (Ra = 0.1–1.6 μm). The friction coefficient of the coating surface is about 0.05–0.08, and the wear life is up to 9–12 km/μm. Furthermore, the adhesion strength of the coating remains 12–14 MPa after 1600 h of salt spray while the wear life of the coating keeps 3–9 km/μm after 720 h of salt spray. The influences of surface roughness (Ra), surface free energy (γOxide), surface potential (φOxide) of the metal substrates and the bonding force at substrate-coating interface on the adhesive energy (Eadh.) are discussed, and the mechanism of "physical-chemical-surface" synergetic enhanced interface adhesion is proposed. The RFP coating is used as the intermediate layer for traditional PU and EP coatings to improve their adhesion on smooth aluminum substrate from 1.39 MPa to 17.5 MPa (increased by 1260 %). Thus, the polymer coating has the potential to provide technical support for the development of long-term anticorrosive coating technology for precision components of marine high-tech equipment.