Wheel Steel Research Articles

High temperature bi-axial low cycle fatigue behaviour of railway wheel steel

One of the most important aspects in railway operation is the interaction between rail and wheel. Railway wheels are commonly made from medium carbon steels (∼ 0.55 wt.% C), heat treated to a near pearlitic microstructure with some 5–10% pro-eutectoid ferrite. During the operation of freight trains, where block brakes are used, high thermal loads are evolved because of recurring braking and occasional slippage. Thus the combination of mechanical and thermal loads leads to changes in the mechanical properties of the material. The focus of the current investigation is to evaluate the mechanical behaviour of wheel material (UIC ER7T) subjected to non-proportional biaxial fatigue loading, as this simulates the actual working conditions in a better way than uniaxial loading. Axial-torsional low cycle fatigue tests were performed at room temperature and elevated temperatures using thin walled specimens to study the cyclic stress-strain properties of this material. The results showed large influence of temperature on the ratcheting behaviour of the material. Biaxial non-proportional loading gave much higher strain hardening as compared to uniaxial loading. Hardening due to dynamic strain ageing can be seen in the biaxial tests at temperatures around 300°C.

基于多个线激光传感器旋转扫描的铸钢车轮在线三维测量技术

基于多个线激光传感器旋转扫描的铸钢车轮在线三维测量技术

EVALUATION OF SAP SYSTEM IMPLEMENTATION IN AN ENTERPRISE OF THE AUTOMOTIVE INDUSTRY – CASE STUDY

Modern businesses boost management by implementing integrated IT systems, such as highly popular in Poland – SAP software, to aid the enterprise resource planning (ERP). This paper evaluates the implementation of an ERP system at a steel wheel rims manufacturer and distributor. The main research method was questionnaire, conducted at the Logistics & Customer Service department. The data acquired from the conducted research were analysed and processed to evaluate the implemented solution. Areas for improvement were pinpointed and concerned the adjustment of the software solution to the needs of the enterprise.

Influence of slip ratio on worn-surface microstructure and fatigue wear behavior of D2 wheel steel

To investigate the worn-surface microstructure and fatigue cracks in D2 wheel steel under the pure rolling and 0.5% slip ratio conditions, a rolling wear test using a GPM-40 wear machine to simulate the wheel/rail operation was performed. After testing, a transmission electron microscope, a scanning electron microscope with electron backscatter diffraction, and micro-hardness testers were used to characterize the microstructure and fatigue cracks. The surface microstructure and hardness of the pure rolling sample were in a steady state after 8 × 104 cycles; however, the 0.5% slip ratio sample reached a steady state after 7 × 103 cycles. Regardless of whether the test uses the slip ratio, the orientation of lamellar pearlites gradually became parallel to the surface and a portion of lamellar cementites was fragmented and dissolved during the formation of steady-state microstructure. The slip ratio accelerates this process. The hardening mechanism of the samples shows a decrease in the lamellar spacing of pearlite and the refinement of proeutectoid ferrite (PF). As the number of cycles increased, plastic deformation of samples became increasingly severe and the wear mechanism of the samples was fatigue wear in steady state. The sample surfaces formed shallow cracks, which gradually peeled off. The slip ratio accelerated the initiation and propagation of fatigue cracks because of the high friction stress on the contact surface. Most fatigue cracks initiated at the interface of pearlite and PF and in the PF region.

Casting of Aluminum Alloy Rod by a Single Wheel with V-Groove

Casting of a convex rod from 5182 aluminum alloy was attempted using a single wheel caster with a V-shape groove. The diameter of the mild steel wheel was 600 mm, the angle of the vortex was 90 degrees, and the width of the groove was 20 mm. Important factors to cast a rod with a convex shape are the speed of the molten metal ejected from a hole-nozzle and the collapse angle between the molten metal stream and the wheel. Important factors that affected the cross sectional shape of cast-bar were the speed of molten metal ejected from the hole-nozzle and the collapse angle of the molten metal against the wheel. A collapse angle close to 90° was better than an angle less than 90°. Casting speeds of 5 m/min and 15 m/min were employed, which resulted in convex cross sectional rod areas of 30 mm2 to 190 mm2.

Analysis and Modeling of Eddy-Current Couplings for Auxiliary Power Generation on a Freight Train Wagon

The subject of this paper is a non-coaxial eddy-current coupling, which can be utilized on a freight train wagon for generating auxiliary power in the range of several Watts. The coupling comprises a wheel with radially magnetized permanent magnets, which is positioned in the vicinity of the wagon’s wheel, and extracts kinetic energy when the train is in motion. A computational method for solving the 3-D problem of the eddy-current coupling is presented. Maxwell’s equations for calculating the excited eddy currents are solved in the Fourier domain with a semi-analytical method (SAM), resulting in computationally efficient simulations. In a case study, the SAM shows 500 times faster simulation times, compared to a 3-D transient eddy-current finite-element method simulation, carried out with a commercially available software. The SAM is verified with measurements taken on two hardware prototypes. Furthermore, in order to generalize the study, a $\rho \eta $ -Pareto optimization of the system is conducted for relaxed design space boundaries, an output power of $P= {\mathrm {10\,\,W}}$ , a C45E steel wheel with $v= {\mathrm {80\,\,km/h}}$ surface velocity, and $g= {\mathrm {3\,\,mm}}$ air gap. It is shown that a power density up to 0.8 kW/dm3 (13 W/in3) and a transfer efficiency up to 60% can be achieved using the proposed system.

Influence of Vanadium on the Microstructure and Mechanical Properties of Medium-Carbon Steels for Wheels

Steels used for high-speed train wheels require a combination of high strength, toughness, and wear resistance. In 0.54% C-0.9% Si wheel steel, the addition of 0.075 or 0.12 wt % V can refine grains and increase the ferrite content and toughness, although the influence on the microstructure and toughness is complex and poorly understood. We investigated the effect of 0.03, 0.12, and 0.23 wt % V on the microstructure and mechanical properties of medium-carbon steels (0.54% C-0.9% Si) for train wheels. As the V content increased, the precipitation strengthening increased, whereas the grain refinement initially increased, and then it remained unchanged. The increase in strength and hardness was mainly due to V(C,N) precipitation strengthening. Increasing the V content to 0.12 wt % refined the austenite grain size and pearlite block size, and increased the density of high-angle ferrite boundaries and ferrite volume fraction. The grain refinement improved the impact toughness. However, the impact toughness then reduced as the V content was increased to 0.23 wt %, because grain refinement did not further increase, whereas precipitation strengthening and ferrite hardening occurred.

Practical investigation of future perspectives and limitations of maglev technologies

Results of an International Survey among Transport Experts and Specialists Maglev.
 With the aim of tracking current trends in the market perspectives of magnetic levitation, or maglev technologies, the non-profit International Maglev Board conducted a primary study in the spring of 2018 among maglev specialists and transportation professionals. More than 1 000 professionals took part in the survey. Main topics of the study are questions comparing the suitability of conventional wheel-on-rail and maglev technologies according to application areas. Predicted opportunities and developments in maglev technology, acceptance issues and research needs are analyzed. The results are broken down by expertise and nationality of the participants. This short version presents selected findings of the survey in compressed form.
 Background: There is an obvious need for information on international trends in the application of Maglev transport technologies. The study attempts to grasp the global dimension of magnetic levitation developments in a structured way.
 Aim: To track current trends in magnetic levitation transport system innovation. Identify perspectives, research tasks and implementation barriers. Comparison of magnetic levitation systems with steel wheel systems. Analysis of the key topics of the debate.
 Methods: Primary study in spring 2018 among 1 058 maglev specialists and transport experts. Internet-based online survey.
 Results: The ratings vary greatly according to the expertise and origin of the respondents. In certain fields of application, wheel-rail systems remain the preferred transport technology. But in certain other fields of application, maglev technologies have become preferred over conventional steel-wheel-rail by a majority of transport professionals. This is particularly the case for high-speed maglev transport and for the new application of maglev elevators in buildings. At the same time, many respondents see a continuing need for research.
 Conclusion: Overall, there is a differentiated picture. Respondents from North and South America, Russia and Asia are on average particularly open to an implementation of certain maglev technologies.

Achievement of high strength-ductility combination in railway wheel steel with thin pearlite and spherical cementite via composition and undercooling design

To achieve high strength and ductility simultaneously, an improved railway wheel steel with high content of Si, i.e., HiSi steel was designed. For comparison, traditional wheel steel of ER8 was also machined from a commercial wheel rim. Then HiSi and ER8 steels were subjected to complete austenitizing followed by water quenching and spray cooling. The stop-cooling temperature during water quenching was about 580, 550 and 520 °C to achieve various degrees of undercooling. Specimens cooled to 520 °C were defined as ER8-520 and HiSi-520. Microstructure characteristics in terms of volume fraction proeutectoid ferrite (VFPF), interlamellar spacing of pearlite (ISP), cementite morphology were examined and mechanical properties including Brinell hardness, tensile properties, Charpy impact properties were characterized. The results indicated that spherical cementite of about 120 nm and submicron plate cementite were achieved simultaneously in HiSi-520 steel. ISP and VFPF in HiSi-520 were 120 nm and 8.9%, respectively. HiSi-520 steel exhibited higher hardness, tensile strength, Charpy impact energy and similar elongation compared to ER8-520 steel. Nanoscale spherical cementite, submicron plate cementite, thin ISP and some proeutectoid ferrite as well as solid solution strengthening from Si and Ni led to the excellent mechanical properties in HiSi-520 steel simultaneously.

Increase of Wear Resistance and Contact-Fatigue Strength of Wheel Steel by Plasma Hardening

Metallographic studies of structural-phase states formed in the section of the flange of the wheel band during surface plasma hardening were conducted. It is shown that the formation of several structural zones of different micro hardness is distinctly observed in the depth of hardening, which indicates the formation of a graded-layered structure. It has been confirmed that at superfast heating rates that occur during surface plasma quenching, phase and structural transformations are shifted to high temperatures, greatly changing the kinetics of nucleation and growth of the new phase (austenite). This forms a fine-grained austenite, which turns into a highly disperse martensitic structure, unattainable by traditional methods of heat treatment. It is shown that the main factor leading to strong hardening of the surface layer during plasma treatment is the formation in the near-surface zone of a nonequilibrium metastable structure, which goes over to a narrow zone of complete and incomplete quenching with an inhomogeneous and distorted structure of highly disperse martensite with a high level of internal stresses. The complete wear of the unstressed flange of the tire wheel band is 1.9 mm in 1.1 years, and for hardened flanges, wear is 0.7 mm for 2.6 years.

The Development of the Method for the Calculation of the Shaping Force in the Production of Vehicle Wheel Rims

The objective of the paper is the development of the method for the calculation of the required force of shaping of a horizontal shape-forming machine used in the preproduction workflow. The design of a machine for horizontal shape-forming of wheel steel rims enables quick readjusting and transfer to another rim shape, which is significant under the conditions of frequent alteration of the product nomenclature. We developed the calculation method based on the assumptions of the deformations continuity, the constancy of the volume at plastic deformation and axisymmetric stressed state as well as the local application of the load. The research resulted in obtaining the analytical dependences for the calculation of the force of shaping of a wheel rim, taking into account the degree of deformation, the mechanical characteristics of the metal, hardening as well as the design and technological factors of the process. The topicality of the development consists in the necessity for the high-quality and the least expensive choice of the equipment of the required rated power when designing a new workflow. The experimental data, carried out both under the production and laboratory conditions, confirmed the adequacy of the theoretical formulas. It is determined by the assumptions and solutions obtained based on the mathematical apparatus of the technical theory of the shells of revolution. The clearness of the method will make it possible to algorithmize the calculation process quite easily and to use it as a subprogram in an applied complex of technical preproduction. It will also allow determining the shaping process most significant factors influencing the value of the force without the direct use of the calculation. We recommend to use it at enterprises producing vehicle steel wheels by the method of radial-rotation shaping.

A Study of the Mechanical Properties of Railroad Wheels Manufactured from a Billet Broached in a Helical Rolling Mill

We describe the results of a full-scale experiment in the fabrication of 957 mm diameter railroad wheels from a pre-formed hollow billet obtained by piercing a thick-walled sleeve with an ingot. We found that a 474 mm diameter steel wheel billet can be smoothly pierced using a rotary piercing mill. The process of forming hollow billets when mass-producing wheels in press-rolling equipment also remains stable. The mechanical specifications of railroad wheels fabricated from hollow billets meet regulatory requirements.

The joint effect of vanadium and nitrogen on the mechanical behavior of railroad wheels steel

Purpose: The aim of the proposed research is to investigate the regularities of the microstructure change, fracture micromechanism and mechanical service characteristics of the high-strength wheel steel with a lowered carbon content under static, impact and cyclic loading depending on the total content of vanadium and nitrogen and also the steel heat treatment modes. Design/methodology/approach: Alloying with vanadium was carried out in the range of 0.09-0.23% and nitrogen in the range of 0.006-0.018%. All steels were heat treated by normalizing and subsequent tempering at different temperatures in the range of 450-650°C. Steels microstructure was investigated by the optical metallography methods on the microscope EPITIP-2 (Carl Zeiss Jena). Scanning electron microscope Zeiss-EVO40XVP was also used for microstructural and microfractography investigations. Static strength (UTS), relative elongation (TEL), impact toughness tests (KCV) and fatigue crack growth resistance characteristics (fatigue threshold ΔKth, cyclic fatigue fracture toughness ΔKfc) were determined on standard specimens. Rolling contact fatigue testing was carried out on the model specimens. Findings: The regularities of the change of microstructure, fracture micromechanism and mechanical characteristics of the high-strength wheel steel with a lowered carbon content under static, impact and cyclic loading depending on the total content of vanadium and nitrogen and also the steel heat treatment modes are studied. Research limitations/implications: The results obtained on laboratory samples should be tested during a real railway wheels investigation. Practical implications: The steel with the optimal parameter [V∙N]∙104 = 22.1% provides high tread surface damaging resistance established on the model wheels. Originality/value: It was established that after normalization at 950°C and tempering at 550°C the increase of ultimate strength UTS and cyclic fracture toughness ΔKfc by 4% and 19%, respectively; impact toughness at room (KCV+20) and low temperature (KCV-40) in 1.5 and 3.3 times, respectively, when parameter [V∙N]∙104 changes from 7.8 to 22.1% and carbon content from 0.63 to 0.57%.

Influences of local laser quenching on wear performance of D1 wheel steel

For wheels and rails during actual service process, due to the combined impact of heat generated by friction and plastic deformation, martensite white etching layers (M-WELs) tend to form on the wear surface of wheel/rail materials. However, M-WELs are regarded as a double-edged sword: their relatively high hardness enhances wear resistance, but during wear process, cracks initiate easily due to great amounts of substructures inside M-WELs. Therefore, local laser quenching is adopted to simulate the wheel surface on which M-WELs form. Investigating the effects of M-WELs on wheels’ tribological properties is conducive to the improvement of high-speed trains’ wheel service longevity. The quenched spot with depth of 250 µm and diameter in 4 mm can be formed after local laser quenching on the specimen surface of D1 wheel steel and the hardness is about 930–997 HV0.1. The effect of the quenched layer on tribological properties of specimens was studied by rolling wear test. The results show that the main fatigue damage of non-quenched specimens is shallow spalling, and cracks propagated along the fibrous structure can be observed. There are striking differences for local quenched specimens. It's obvious that cracks initiate easily at the edge of the quenched layer as well as the quenched layer surface, and then propagate along the heat-affected zone at the early worn stage. This leads to spalling of the edge of the quenched layer. Cracks initiated on the surface can extend towards the bottom of the quenched layer with the increase of rotation cycles and the convergence of cracks would result shallow spalling of the quenched layer. After the edge of the quenched layer falls off completely, cracks initiate in the heat-affected zone and propagate along the heat-affected zone or along the fibrous structure of the matrix, leading to shallow spalling. In the subsequent process of rolling wear, cracks extend to the heat-affected zone and continue to propagate along this zone to the area where the maximum shear stress exists; under the impact of the maximum shear stress, the cracks further expand to the matrix. However, if these cracks converge other ones before arriving at the heat-affected zone, large pieces of the quenched layer fall off. The quenched layer can not only accelerate the surface spalling damage of the specimen and wear unevenly, but also can promote the formation of polygonization and reduce wear resistance of the specimen under axial vibration condition.

Model-based correlation between change of electrical resistance and change of dislocation density of fatigued-loaded ICE R7 wheel steel specimens

Abstract Weight-optimized component design as well as a reliable estimation of the lifetime of metallic materials and components require a comprehensive understanding of fatigue processes and a systematic investigation of the underlying fatigue behavior. This becomes even more important when designing highly loaded components such as wheels of high-speed passenger railway systems. Typically, mechanical stress-strain hysteresis measurements and increasingly different types of temperature and electrical resistance measurements are used to characterize the fatigue behavior and fatigue processes. Here, electrical resistance measurements provide significant information as they allow the detection of microstructural changes, e. g., through changes in dislocation density and structure. In addition, electrical resistance measurements can be considered in load increase and constant amplitude tests with inserted load-free sequences and in service load tests to characterize damage progress. In this paper, characteristic values of the change in electrical resistance were determined for ICE R7 wheel steel specimens and correlated with dislocation density, which was load- and cycle-dependent and determined through transmission electron microscopy.

STUDY OF WEAR RESISTANCE OF REINFORCED POLYAMIDE COMPOSITES FOR METAL-POLYMER GEAR DRIVES

An experimental study of the wear resistance of two dispersion-filled composite materials based on polyamide used in metal-polymer gear drives with a 30% volume content of short glass or carbon fibres was performed according to the technique proposed by the authors. As a result of tribotests in the “pin-disk” scheme, the mass wear of these composites was determined under dry friction conditions for steel 45 at room temperature in the range of contact pressures of 10–40 MPa, as well as the kinetics of the coefficient of sliding friction and the contact temperature of the tribosystem elements. It was established that polyamide strengthened by carbon fibres has almost four times higher wear resistance in comparison with a polyamide filled with glass fibres. The wear resistance characteristics that are the basic parameters of the tribokinetic wear model are calculated, using the durability of the straight spur metal-polymer gear drive on the basis of the original calculation method. It was established that gear drive durability with a pinion or a wheel reinforced with carbon fibres is more than eight times the durability of gear drive with gear wheels from polyamide filled with glass fibres. The gear drive durability with the steel pinion and the composite gear wheel increases in proportion to the gear ratio as compared to the gear drive with the composite pinion and the steel wheel. The change in the maximum contact pressures in the mesh interval was calculated.

Shape Optimization of Passenger Vehicle Wheel on Fatigue Failure

Based on the basic passenger vehicle steel wheel shape design, revised design was proposed to solve the common fatigue failure problems. Both basic and optimized design were modeled using Abaqus 3D software to calculate the stress and strain contours in the case of bending load and radial load. Consequently, fatigue life contours of models for each load case were calculated with the help of Brown-Miller biaxial fatigue theory. It was shown that, at the condition of unchanged wheel material and number of disc vents, optimized rim profile can extend fatigue life index of disc by 73.8% and 58.5% under bending load and radial load respectively. Meanwhile, the fatigue life index of rim could be extended by 17.5% and 134.4% under bending load and radial load respectively.

“DESIGN & OPTIMIZATION OF ALLOY WHEEL RIM USING ANSYS”

Alloy wheels are automobile wheels which are made from an alloy of aluminum or magnesium metals or sometimes a mixture of both. Alloy wheels differ from normal steel wheels because of their lighter weight, which improves the steering and the speed of the car. Alloy wheels will reduce the unstrung weight of a vehicle compared to one fitted with standard steel wheels. The benefit of reduced unstrung weight is more precise steering as well as a nominal reduction in fuel consumption. Alloy is an excellent conductor of heat, improving heat dissipation from the brakes, reducing the risk of brake failure under demanding driving conditions. At present four-wheeler wheels are made of Aluminum Alloys. In this project, Aluminum alloy are comparing with another Alloy. In this project a parametric model is designed for Alloy wheel used in four-wheeler by collecting data from reverse engineering process from existing model. Design is evaluated by analyzing the model by taking the constraints as ultimate stresses and variables as different alloy materials and different loads and goals as maximum outer diameter of the wheel and fitting accessories areas like shaft of the axle and bolts PCD of the car. Car model is Toyota.

Experimental and Numerical Investigation of the Thermal Effects on Railway Wheels for Shoe-Braked High-Speed Train Applications

An improved railway wheel steel containing higher contents of C, Mn, Si, and V than the traditional ER7 steel was developed by alloy design for shoe-braked high-speed train applications. The effects of the thermal load on the microstructure and mechanical properties of a wheel made from this steel were investigated using a combined experimental and numerical approach. The wheel braking was studied using finite element simulations that account for the thermal loading of the wheel in order to find the temperatures reached in the wheel rim. Hardness measurements, tensile tests, toughness tests, fatigue crack growth tests, and microstructural observations were carried out on samples extracted from real wheels, with and without heat treatments simulating the modification of the microstructure due to the shoe braking. The results on the un-treated samples showed that the improved steel has a better combination of strength and toughness than ER7 steel. The results on the heat-treated samples showed that the improved steel maintains acceptable mechanical properties provided the maximum temperature during braking is below the A3 temperature of the steel (around 790 °C).

Influence of non-metallic inclusions and products of corrosion on the wear of railway wheels tread

Formulation of the problem . It is of interest to investigate the effect of nonmetallic inclusions and corrosion products of wheel steel on the formation of wear particles on the tread of railway wheels. It is also necessary to identify the specifics of the interaction of wheel steel with the surrounding atmosphere during the operation of railway wheels. The purpose of the article is to study the mechanisms of formation of wear particles on the surface of rolling of railway wheels during operation. Methodology . The effect of inclusions and corrosion products on the mechanism of wear of railway wheels made of R7 steel, which worked for about 5 years under the passenger train, was studied. The wheels were removed from service due to the extreme wear of the rims. We studied the macrostructure and microstructure of wheel steel along the width of the rims. The research was carried out by several methods: metallographic (Neophot−21), electron microscopy (JSM−35). Findings . The features of the formation of wear particles near nonmetallic inclusions and corrosion products related to structural changes near the rolling surface of railway wheels as well as to the interaction of steel with the surrounding atmosphere during operation were investigated. The influence of various factors on the role of nonmetallic inclusions and corrosion products in the formation of wear particles is shown, which makes it possible to predict the nature of wear of the rolling surface of railway wheels under various operating conditions. Originality . The main sources and the mutual influence of various factors on the formation of wear particles near nonmetallic inclusions and corrosion products have been established, which makes it possible to predict the nature of wear of the rolling surface of railway wheels under various operating conditions. Practical value . The use of the obtained results will allow to develop methods and regimes of smelting of wheel steel, allowing to influence the size, composition, structure and distribution of non-metallic inclusions, as well as to develop anticorrosion measures in order to improve the reliability and durability of railway wheels.