Friction Of Steel Research Articles

The electrified tribological behavior of TiN coating in lubricated contacts

Abstract The excellent conductivity of TiN coatings holds promising potential for application in electrified
mechanical systems. This work investigated the friction and wear behavior of TiN coating in
electrified contactswhen lubricated with fourbase oils: poly-α-olefin, mineral, rapeseed, and castor
oils. The results indicated that the electric current significantly induced stick-slip friction. Higher
currents led to a slow increase in friction for hydrocarbon oils, whereas a gradual decrease in
friction was observed for castor oils. The steel friction pair underwent notable wear under
electrified contact conditions due to the current-induced tribo-oxidation. TiN coating displayed
obvious negative wear characteristics when lubricated with hydrocarbon oils under current
conditions The tribo-layer. on the friction surfaces, comprising iron oxides and graphite-like carbon,
was linked to the electrified friction and wear behavior. The electrically promoted lubricant
degradation and tribo-oxidation of the steel pair emerged as universal features in electrical contacts.

Machine learning prediction of mechanical properties in stir zone of 310 austenitic steel friction stir welds

Machine learning prediction of mechanical properties in stir zone of 310 austenitic steel friction stir welds

Study on the effects of the shot peening intensity on the microstructure, friction and wear properties of high-strength steel.

The microstructure, hardness, residual stress, and friction and wear properties of 25CrNi2MoV steel with different particle diameters during shot peening strengthening were studied. Studies have shown that a grain refinement layer appeared on the surface of the material after shot peening. The shot peening intensity increased with increasing particle diameter; a greater shot peening intensity corresponded to a greater surface hardness of the material, the maximum hardness was 592 HV0.2, and the residual compressive stress on the material surface was 725 MPa. A shot peening finite element model was established to accurately predict the residual stresses in the samples after shot peening. The prediction errors were 1.4-7.9%. The finite element model indicates that the maximum residual stress occurs in the subsurface layer. After shot peening, the wear resistance of the sample significantly improved, and the amount of wear significantly decreased. Therefore, shot peening can significantly improve the mechanical properties and wear resistance of high-strength steel, which increases the service life of parts.

Role of microstructure on the varying corrosion behavior across the UNS S32750 super duplex stainless steel friction stir weld

Role of microstructure on the varying corrosion behavior across the UNS S32750 super duplex stainless steel friction stir weld

The influence of laser-induced tempering on the microstructure and mechanical properties of 1500 MPa martensitic steel friction stir welded joints

A comprehensive comparison illustrates the role of laser technology in altering the macro morphology and microstructure of martensitic steel joints produced by friction stir welding (FSW). In this study, laser-induced tempering (LIT) was introduced to the FSW of 1500 MPa martensitic steel. The mechanism by which LIT enhanced the mechanical properties of the FSW joints was elucidated by comparing joints produced with and without LIT. Experimental findings revealed that LIT effectively eradicated tunnel defects under the same FSW parameters. Even with an increase in travelling speed from 60 mm/min to 120 mm/min, flawless welds were achieved under LIT conditions. At 500 rpm and 60 mm/min, the bottom of the stir zone (SZ) in conventional FSW (C-FSW) joint exhibited a ferrite and martensite dual-phase microstructure. In contrast, the SZ of the LIT-FSW joint had a fully martensitic structure. Moreover, LIT resulted in significant variations in the martensitic hierarchical structure within the SZ. LIT reduced ferrite distribution in the dual-phase zone, caused recrystallized ferrite to appear further from the SZ. The stress concentration in the dual-phase zone attributed to joint fracture. The improvement in the mechanical properties of martensitic steel FSW joints was explained by analyzing the correlation between the stress concentration factor and phase fraction. Additionally, the increase in traveling speed narrowed the dual-phase zone, triggered a constraint effect that led to a maximum ultimate tensile strength (UTS) increase from 986 MPa at 60 mm/min joint to 1142 MPa at 120 mm/min joint.

Enhanced tribological properties of sliding contacts through the synergistic effect of PTFE film and PSAIL 2280

PurposeThe purpose of this study is to investigate the effectiveness of a composite lubrication system combining polytetrafluoroethylene (PTFE) film and oil lubrication in steel–steel friction pairs.Design/methodology/approachA PTFE layer was sintered on the surface of a steel disk, and a lubricant with additives was applied to the surface of the steel disk. A friction and wear tester was used to evaluate the tribological properties and insulation capacity. Fourier transform infrared spectrometer was used to analyze the changes in the composition of the lubricant, and X-ray photoelectron spectroscopy was used to analyze the chemical composition of the worn surface.FindingsIt was found that incorporating the PTFE film with PSAIL 2280 significantly enhanced both the friction reduction and insulation capabilities at the electrical contact interface during sliding. The system consistently achieved ultra-low friction coefficients (COF < 0.01) under loads of 2–4 N and elucidated the underlying lubrication mechanisms.Originality/valueThis work not only confirm the potential of PTFE films in insulating electrical contact lubrication but also offer a viable approach for maintaining efficient and stable low-friction wear conditions.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2024-0222/

Experimental Study on Enhancement in the Tribological Behaviour of Military Grade Lubricant Using Titanium Dioxide Nanoadditives for Aerospace Applications

ABSTRACTThe coefficient of friction of low carbon chromium alloy steel with military grade lubricant was high, resulting in increased heat generation and temperature rise of the lubricant in the aircraft power transmission units such as engine gearbox, accessory gearbox and so on. To address this, the current research proposes the addition of TiO2 nanoparticles to MIL grade lubricant as an additive to enhance the tribological performance. In this experimental study, TiO2 nanolubricant was prepared using various surfactants for better suspension of TiO2 nanoparticles, and properties were evaluated for both base lubricant and nanolubricant. The tribological experiments were conducted using a four ball tester, a shear stability tester and a reichert tester. In a four ball test, TiO2 nanolubricant resulted in a 27.3% reduction in wear scar diameter by the addition of TiO2 nanoparticles to the base lubricant. In a shear stability test, TiO2 nanolubricant showed 80% better shear stability than the base lubricant. In the reichert test, the coefficient of friction was reduced by 13% with the TiO2 nanolubricant. The experimental findings demonstrated that the TiO2 nanoparticles, as an additive to a military grade lubricant, have superior tribological properties for aerospace applications.

Optimizing weld strength and microstructure in CP-titanium and 304 stainless steel friction welds with chromium interlayer

This study investigates the effect of a Cr-interlayer on the hardness and friction-welded joint strength between CP-titanium and 304 stainless steel. Rotary friction welding, with its adjustable parameters such as upset pressure, is the preferred method for this dissimilar joint. Due to the difference between these two base metals, a metallic interlayer like chromium, is crucial for controlling the formation of intermetallic compounds (IMCs). Welding was conducted at three different upset pressures, both with and without the Cr-interlayer. Tensile and microhardness tests were performed, complemented by phase analysis and microstructural characterization using XRD and SEM. Our findings reveal that employing a chromium layer and higher upset pressures enhances strength while reducing the presence of brittle IMCs in the welds. At the CP-titanium side, dynamic recrystallization occurs due to increased heat generation at the interface and strain occurred by materials flow, facilitating IMC formation, especially evident at 250 MPa upset pressure. Interestingly, relatively higher strength at 150 MPa is attributed to the absence of IMCs. Conversely, higher strength results at 350 MPa due to from the flow of softened material, effectively purging IMCs from the weld zone. Notably, both β-titanium and chromium-based IMCs form in the presence of the chromium interlayer, resulting in decreased joint hardness and increased overall ductility. In conclusion, our study's findings contribute to bridging the gap between theoretical strength and practical application, significantly advancing joint performance.

Evaluation of the tribological performance and oxidative stability of a bi-functional lubricating oil additive prepared from corn cob extract

To meet the requirements of a circular economy, a class of sulfur- and phosphorus-free green bifunctional lubricating oil additives was developed based on corn cob extract as a naturally renewable biomass material. These additives can significantly enhance the friction-reducing, anti-wear properties, and oxidative stability of base oils. Results indicate that at an addition level of 4000 ppm, ternary polymer additive reduced the wear volume and surface roughness of steel friction pairs by 98.17 % and 97.63 %, respectively, and increased the oxidation induction period by 40.52 %. The improvement in tribological performance is attributed to the rigid ring structure preventing direct contact between friction pairs, and the chemical adsorption of carboxylic acid and anhydride groups with the metal, forming a dense friction film.

Enhancing Lubrication Performance of Ga–In–Sn Liquid Metal via Electrochemical Boronising Treatment

ABSTRACTAs one of the liquid metals, Ga–In–Sn liquid metals can function as an advanced lubricant with high conductivity in a tribology system. It has already revealed advancements in several applications, such as coolants and electromechanical relays. However, Ga–In–Sn liquid metal shows poor lubrication performance on industrial metallic materials, which limits its application in engineering. In this study, the electrochemical boronising strategy was applied to improve the lubrication effect of Ga–In–Sn liquid metal on steel friction pairs. Electrochemical boronising treatment was performed to the base material AISI 52100, and a boronised layer with a thickness of around 64 μm was generated. Tribology tests were carried out on both boronised and original samples with the lubrication of Ga–In–Sn liquid metal (68.5 wt% Ga, 21.5 wt% In and 10 wt% Sn). Results show that the wear resistance of the tribo‐system reveals great improvement: The coefficient of friction decreases by 59% and the wear rate drops 85% compared to the steel/steel friction pair. EDS and XPS results show that a tribofilm consisted of Fe/Ga was in situ–generated on the wear scar of the boronised sample, which results in the synergy effect between the boronised layer and the Ga–In–Sn liquid metal. Therefore, we provided a robust strategy to enhance the lubrication performance of Ga–In–Sn liquid metal on a steel friction pair by using electrochemical boronising treatment, which could broaden the application field of Ga–In–Sn liquid metals.

Excellent tribocorrosion resistance in artificial seawater of high entropy alloy FeCrNiCoAl coating prepared by HVOF

In marine environments, steel friction pairs undergo significant degradation due to the combined effects of wear and corrosion, known as tribocorrosion. This study investigates the tribocorrosion behavior and mechanisms under high loads of a High Entropy Alloy (HEA) FeCrNiCoAl coating applied by HVOF spraying, as well as cast ingot FeCrNiCoAl and 304SS samples, in artificial seawater. The investigations were conducted using electrochemical methods and in situ wear- electrochemical techniques. The tribocorrosion rate of the HVOF coating is approximately 1/5 that of the HEA cast ingot and 304SS samples. This is attributed to the coating's high hardness and the supporting and isolating effects of its oxide layers between splats. An intriguing finding is that the Open-Circuit Potential (OCP) trough value of the HVOF coating coincides with the peak Coefficient of Friction (COF) value during tribocorrosion in artificial seawater. This is due to the exposure of fresh surfaces following the local peeling off of flattened particles. Furthermore, the coating exhibits high re-passivation capabilities during wear because of high oxygen content in the coating. In comparison to corrosion, wear-induced material loss was identified as the primary contributor (≥ 99.8 %) to mass loss in both HEA cast ingot and coating samples. Optimizing the quantity and morphology of the HVOF coating has the potential to further enhance its tribocorrosion resistance. This study lays the foundation for developing advanced tribocorrosion-resistant coatings for use in seawater environments.

Adhesive built-up edge on tool steels due to friction and wear

When processing metals by cutting, there are a number of materials prone to growth. This phenomenon leads to a change in the geometry of the cutter, cutting forces and surface quality, final dimensions of the part. In friction nodes: shaft-sleeve, piston-sleeve, etc. this phenomenon causes jamming. In this work, experimental studies of the processes of dry friction of tool steels with coatings were carried out to evaluate the effectiveness of reducing the growth process. As a result, it was established that the nature of formation, destruction and size of growth of materials prone to growth depends on the chemical composition of the material and modes of friction. High-strength chromium-manganese steels are most prone to growth and microseizures. It is shown that the well-known recommendation of increasing speed cannot always be used to prevent build-up, but it can be achieved by using single-layer and multi-layer coatings with a defect-free structure and moderate friction modes. It was found that electrolytic single-layer nickel and chromium coatings contribute to the formation of growth on the studied materials and this phenomenon does not depend on the modes of friction, while the same chemical coatings, which have an almost defect-free structure, are almost not prone to growth formation.

Effect of carbonitride on the friction and wear properties of M50NiL steel after sequential carburizing and nitriding treatment

In this work, M50NiL steel was carburized at 950 ℃ for 1 h (C samples) and subsequently nitrided at 520 ℃ for 7 h (CN samples). The carbonitrides of the samples that underwent the sequential carburizing and nitriding treatment were observed before and after wear and analyzed via SEM, FIB, and TEM. The friction and wear properties of the CN samples were compared with those of the C samples. The results show that the surface hardness and surface residual stress of the CN samples were 1.6 and 4.2 times greater than those of the C samples, respectively, i.e., the CN samples were less likely to spall during wear. The carbonitride particle sizes of the CN samples were 100–500 nm before wear and less than 10 nm after wear, indicating that carbonitrides enhanced the wear resistance of the CN samples. The wear area of the CN samples decreased by 95.6 % at 20 N and 87.4 % at 40 N.

Tribological properties of diamond-like carbon films lubricated with water-emulsified engine oil

In this work, the tribological properties of two diamond-like carbon (DLC) films were investigated at different temperatures using water-engine oil emulsions as lubricants, considering emerging fuel systems such as hydrogen and ammonia. The results revealed that the friction coefficient of a-C film raised with the increasing water content at 80 °C. The friction coefficient of a-C:H film initially raised and then decreased with varying water fractions at different temperatures. Elevated temperature exacerbated the wear of both DLC films at high water contents. The most significant wear was observed for a-C film at 80 °C and a-C:H film at 50 °C. The a-C:H film exhibited more sensitive wear characteristics to water content than the a-C film. Surface analysis indicated that water-engine oil emulsions prevented the formation of phosphate tribo-film on steel friction pair for two DLC films but promoted the tribo-oxidation of steel pair sliding contact with a-C film, especially at higher temperatures. Distinct reactivities of two DLC films towards water molecules could affect the adsorption of lubricants on DLC surfaces, leading to their different friction and wear behavior. It suggests that the water-caused emulsification of lubricating oil will be a pivotal consideration in tribological applications of DLC films in future internal combustion engines.

Study on ultra-low friction performance of PTFE film combined with water-based ionic liquid lubrication at electrical contact interfaces

By polytetrafluoroethylene (PTFE) films on the surface of steel disc and using water-based ionic liquids as lubricants, the solid-liquid synergistic effect of PTFE films and water-based ionic liquids was systematically investigated. The results showed that PTFE films exhibited excellent tribological performance and maintained good insulation capabilities under electrical conditions in the sliding electrical contact interface. When using water-based lactate Ionic liquids as lubricants, the PTFE film achieved a COF of less than 0.01 under a load of 2 N, realizing ultra-low friction. The analysis of the lubrication mechanism revealed that two types of protective films were formed on the PTFE film and steel friction pair surfaces. These protective films effectively prevented direct contact between the friction pairs, significantly enhancing tribological performance.

Study on the Lubrication Performance of Graphene-Based Polyphosphate Lubricants in High-Temperature Steel–Steel Friction Pair

In the study, a hybrid lubricant was prepared by introducing graphene into a polyphosphate lubricant. In the tribological test of a steel/steel friction pair at the high temperature of 800 °C, the addition of a small proportion of graphene significantly enhances the lubrication performance of polyphosphate at elevated temperatures. The coefficient of friction and the wear were obviously held down while the surface quality of the high-temperature friction pair was enhanced effectively with the graphene-strengthened polyphosphate lubricant, compared with the dry sliding condition. Through scanning electron microscopy and Raman spectroscopy analysis, the formation mechanism of tribofilm and the antiwear performance of the hybrid lubricant are further explained. This lubricant effectively combines the advantages of both; the combination of polyphosphate melted at elevated temperature with graphene and metal surfaces ensures the self-sealing of the friction contact area and brings better high-temperature oxidation resistance. At the same time, the presence of graphene provides excellent strength to the friction film and ensures the anti-wear and wear-resistant performance of the lubricant at high temperatures.

Effect of temperature on the tribological behavior of additively manufactured tool materials in reciprocating sliding against cemented carbide

Additive manufacturing (AM) of ferrous alloys has achieved a technological maturity level that allows for the production of high-performance steel components. Among these alloys, tool steels and maraging steels can be used in die manufacturing for different hot forming processes as both materials have good mechanical properties and thermal stability. In recent years, several works have successfully produced these alloys through selective laser melting, focusing on the optimization and characterization of their microstructure and mechanical properties. However, few studies look into the tribological aspects of these newly produced materials and even fewer consider high temperature friction and wear performance. Therefore, there is a need to understand the high temperature tribological response of tool materials produced by additive manufacturing. In this context, the aim of this work is to investigate the tribological behavior of a tool steel and a maraging steel, both produced by selective laser melting, at different elevated temperatures. A conventionally produced tool steel was used as reference. A reciprocating sliding tribometer was used to perform tests at 40 °C, 200 °C and 400 °C. The counter-body was a WC-Co cemented carbide. Friction and wear of the AM tool steel and reference tool steel were very similar, thus no signs of the AM route having an impact on the tribological behavior were observed. Both tool steels showed reduced wear volume with increasing temperature, while the opposite was observed for their respective WC-Co counter-bodies. Higher temperature also resulted in increased amount of W transferred onto the tool steel wear scars. AM maraging steel showed higher and more unstable friction level, as well as a much larger wear volume at all temperatures; material transfer onto WC-Co was observed at certain temperatures. Overall, tribolayer formation (or lack thereof) was the dominant aspect in the tribological responses.

Influence of Chloride Concentration on Fretting Wear Behavior of Inconel 600 Alloy.

The nickel-based alloy Inconel 600, strengthened by solution treatment, finds extensive application as a heat exchange pipe material in steam generators within nuclear power plants, owing to its exceptional resistance to high-temperature corrosion. However, fretting corrosion occurs at the contact points between the pipe and support frame due to gas-liquid flow, leading to wear damage. This study investigates the fretting wear behavior and damage mechanism of the nickel-based alloy Inconel 600 and 304 stainless steel friction pairs under point contact conditions in a water environment. Characterization was performed using laser confocal scanning microscopy and scanning electron microscopy equipped with energy-dispersive spectroscopy. Results indicate that the friction coefficient remains consistent across different chloride ion concentrations, while the wear volume increases with increasing chloride concentrations. Notably, friction coefficient oscillations are observed in the gross slip regime (GSR). Moreover, the stability of the oxide layer formed in water is compromised, diminishing its protective effect against wear. In the partial slip regime (PSR), friction coefficient oscillations are absent. An oxide layer forms within the wear scar, with significantly fewer cracks compared to those within the oxide layer in the GSR. It is worth noting that in GSR, the friction coefficient oscillates.

Fabrication of gradient structure for enhancing wear resistance of GCr15 bearing steel friction shim

The wear resistance of metallic shims under heavy load is crucial for the friction behavior of friction damper in civil engineering. This study verifies the potential of the strengthening grinding process (SGP) to enhance the wear resistance of metallic materials under heavy load. A multidisciplinary effort is shown in this paper to investigate the wear mechanism of SGP-treated GCr15 bearing steel in terms of the application scenario of civil engineering. The SGP treatment uses a multiphase abrasive comprising steel balls, corundum powder, and strengthening liquid to impact the surface of the GCr15 bearing steel. Then, a dry friction sliding test was performed on the polished, sandblasted, and SGP-treated GCr15 bearing steel. The microtopography and microstructure of these three friction shims with different treatments before and after the wear test were compared and analysed. The test results indicated the feasibility of SGP in enhancing the wear resistance of GCr15 bearing steel friction shims under heavy loads in terms of the application scenario of civil engineering. The SGP-treated sample had a more stable friction coefficient (0.475) and slighter wear compared to the other two samples due to its enhanced layer with a gradient structure and a thickness of approximately 23 μm.

Effects of graphene addition on the mechanical, friction and corrosion properties of laser powder bed fusion 316L stainless steel

Laser powder bed fusion of 316 L (LPBF-316 L) has been known to exhibit high ductility but low strength, along with strong corrosion resistance and weak anti-friction properties. Graphene is commonly utilized as a reinforcement phase in metals fabricated through LPBF, as this process helps reduce the tendency of graphene to agglomerate. Therefore, it is crucial to investigate the impact of incorporating graphene into the LPBF-316 L alloy, aiming to enhance toughening and anti-friction properties while maintaining the original corrosion resistance. Various concentrations of graphene were incorporated into 316 L powder and processed using LPBF. The study examined the impact of graphene concentration on the electrochemical, mechanical, and friction properties of the resulting composites. The study revealed a significant reduction in corrosion current from 8.05 ± 0.6 × 10−7 A/cm2 to 6.61 ± 0.8 × 10−8 A/cm2. The 15-day immersion experiment further validated that the incorporation of graphene contributed to enhancing the stability of corrosion resistance. Additionally, the presence of graphene led to improved strength and ductility in LPBF-316 L through grain refinement and precipitation. Notably, samples containing 0.2 wt% graphene exhibited a tensile fracture strength of 927.4 MPa and ductility of 54.75%. In addition, the compressive fracture strength of 2342.8 MPa, both surpassing that of LPBF-316 L. Furthermore, the study investigated the impact of graphene content on the friction of LPBF-316 L, revealing that graphene addition increased matrix hardness, reduced COF, and enhanced wear resistance. Overall, the findings suggest that graphene serves as an effective reinforcing agent for 316 L stainless steel matrix composites, enhancing mechanical properties, friction resistance, and wear resistance while preserving original corrosion resistance.