Induction Surface Hardening Research Articles

State of the Art and Future Trends in Monitoring for Industrial Induction Heating Applications

Induction surface hardening (ISH) processes are widely used in the heat treatment of numerous industrial components, especially in the automotive industry. Since this industry operates under very demanding quality standards, it is crucial for these heat treatment processes to meet rigorous specifications to ensure the safety and reliability of the produced components. This implies the precise and repeatable control of certain parameters throughout the manufacturing process of each of the parts treated, through precise and reliable instrumentation in electromagnetically harsh environments. The main objective of this work is to define the monitoring process for an industrial IHS application, determining the control needs and the methods of measurement, recording, and verification of the parameters that ensure the quality of the process. This paper describes the monitoring process of induction surface hardening, emphasizing the use of sensors and modern measurement and control systems. A comprehensive monitoring system supported by a programmable logic controller (PLC) and mixed acquisition and instrumentation systems (analog and digital) implemented with a high-performance Field Programmable Gate Array (FPGA) will be presented.

Characterization of Cr-TiB2 composite coating on AISI 1045 steel using hybrid deep neural network-based sandpiper optimization algorithm

The scope of this study is to enhance the performance of AISI 1045 steel for demanding marine applications like connecting rods, axles, and wear-resistant components. Traditional heat treatment methods, including boriding, surface induction hardening, and tempering, improve the steel’s surface hardness. Additionally, the Tungsten Inert Gas (TIG) coating process develops a novel Cr- TiB2 composite coating on the heat-treated AISI 1045 stainless steel. The investigation explores the influence of varying TiB2 content (10%, 20%, and 30%) on the mechanical properties of AISI 1045 steel. Microhardness and tensile characteristics are analyzed, considering the impact of TiB2 percentage. Surface morphology and interfacial bonding are examined using Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Analysis (EDAX). Results reveal notable improvements, including a 2.65 times increase in microhardness compared to untreated AISI 1045 steel, uniform TiB2 distribution, and a crack-free coating. The addition of TiB2 particles in the Cr- TiB2 composite coating enhances microhardness. Improved mechanical properties are attributed to surface treatments, incorporation of hard and wear-resistant materials (Cr and TiB2) in the composite coating, microstructure modifications, and crack prevention, collectively resulting in increased hardness, wear resistance, and durability. Furthermore, this study introduces a novel hybrid Deep Neural Network-based Sandpiper Optimization Algorithm (DNN-SOA) for predicting experimental outcomes with superior accuracy. This research not only enhances the understanding of the coated steel’s mechanical properties but also presents an innovative predictive model for future material engineering applications, demonstrating the significance of advanced heat treatment and a novel composite coating in improving AISI 1045 steel performance.

Comparison of Surface Hardening Processes Applied to AISI 5140 Steel withSide Load Test

AISI 5140 Tempered steel is generally preferred in the joints of vehicles. This steel is a material with high toughness. Its usage areas are quite wide. The purpose of the surface hardening process is to increase the wear resistance of surfaces exposed to wear, as well as to increase the fatigue life of the part and increase corrosion resistance. Since the inner parts of the parts are not affected by surface hardening, the resistance to impacts increases and therefore the formation of cracks on the surface is delayed. Surface hardening processes delay the formation of cracks on the surface and extend fatigue life. In this study, a comparison was made between a part with induction surface hardening, which is one of the methods in which the chemical composition of the surface is not changed, a part with nitration, which is one of the methods in which the chemical composition is not changed, and a part with standard reclamation heat treatment. Side Load test, a static testing method, was used for this comparison. In the Side Load test, the samples were compressed from the conical region and a vertical load was applied corresponding to the center of the joint. According to the results obtained in the tests, the sample with Induction surface hardening process withstood 64500 N, the sample with Nitriding heat treatment withstood 54500 N and the sample with Standard tempering heat treatment withstood 50200 N. According to the results obtained, the sample with the highest durability rate is the sample whose surface was hardened by induction.

Mathematical modelling of thermal stresses of induction surface hardening in axi-symmetric formulation

The paper presents the original general model of induction surface hardening based upon analysis of coupled electromagnetic, thermal, mechanical and metallurgical phenomena. The distribution of mechanical strains and stresses in surface layers of steel materials subjected to induction hardening is determined. This distribution is not caused only by the thermoelastic processes, but often, it is also influenced by plastic deformations of the exposed layers and transformation of particular levels of steel. An illustrative example shows the methodology of solution for an axi-symmetric configuration.

Challenges of Numerical Simulation Models for Induction Surface Hardening of Large Bearing Rings

Abstract Induction hardening of large bearing rings is a very challenging procedure due to the complex physical processes and their interactions, which need to be properly controlled to produce components meeting the imposed requirements of e.g. wind turbines. The different process parameters significantly alter the resulting microstructures and properties of such a bearing ring. The evolution of numerical simulations in the last decades allows the modelling of processes with a growing complexity. In this work, the challenges of a simulation model for induction surface hardening are shown and discussed. Besides the theoretical background of the interacting physical fields and a brief note about available software packages, the paper focusses on the elaboration of a necessary material database and on the specific problems of induction scan hardening processes for large bearing rings.

Failure analysis of an axle shaft in an airport ground support vehicle

In this study, failure analysis of an axle shaft in an airport ground support vehicle was carried out to determine failure mechanism, failure root causes and preventive actions. Macroscopic observation, numerical analysis, metallographic analysis, chemical composition analysis, hardness measurement and tensile test methods were used in failure analysis. In numerical fatigue analyses, axle shaft was modelled as a functionally graded material due to mechanical properties changing in the material radial section as a result of induction surface hardening. The analysis results showed that the failure mechanism of fractured axle shaft was torsional fatigue. High surface roughness and insufficient mechanical properties were found as failure root causes. Making finish cut with low depth and even grinding in surface finishing process were proposed as a prevention to increase surface quality, reduce surface roughness and stress concentrations in machining of axle shaft. In addition, using another material with higher yield strength (EN 37Cr4) was proposed instead of EN 34Cr4 alloy steel as the axle shaft material.

Моделирование технологических параметров индукционной поверхностной закалки на основе обобщенных экспериментальных исследований

The article discusses the modeling of induction surface hardening technology of low-alloy carbon steels with a carbon content of 0.2 to 0. 8 %. To optimize technological parameters, such as heating power and time, current frequency and quenching depth, experimental data were generalized: dependences of austenization and homogenization temperatures heated steel on the heating rate, carbon content and grain size of the initial structure. Also, on the basis of experimental data, the dependences of austenite grain growth on the heating rate and temperature are obtained. A nonlinear coupled electrothermal numerical model was used in the work, in which the calculation of the nonlinear ferromagnetic problem was carried out in the time domain. To study the effect of phase transformations during induction heating on the choice of the optimal heating mode, an iterative algorithm was developed that controls the numerical electrothermal model. The article compares the results of simulation of induction surface hardening modes for cylindrical bodies made of St35 and St45 steels, and also provides the required surface heating temperature. The influence of the initial structure on the choice of heating mode is shown. In addition, the developed model makes it possible to predict the ultimate hardness on the surface of the hardened part for optimal cooling mode.

Program complex for optimization of surface hardening of steel billets

The aim of the paper is to develop program complex in software MATLAB with integrated numerical 2D nonlinear FLUX model, which is used for solving optimal inductor design and control problems for heating stage of surface induction hardening. Considered program complex is based on alternance method, that allows to write systems of transcendental equations, closed with respect to all unknown design and control parameters of the process. The suggestion for implementation of obtained optimal control algorithm is presented.

Induction Surface Hardening: a review

One of the methods of surface hardening the majority extensively used surface hardening procedure which can be used in many metals in their entirety in today’s applications. Induction coil is concentrated to the localized area where the necessary piece is hardened of the material. A high inductance coil is used to heat the surface of steel into the austenitic region. High heat transformation rates result in instant quenching by oil, resulting in a steep temperature gradient. This method necessitates external quenching because it induces phase conversion from austenite to martensite. This review paper ensures an overview of the principles of induction surface hardening, as well as some of its advantages over traditional hardening techniques. The results of experiments and computational approaches reported by different researchers are discussed.

Развитие технологий индукционного нагрева

In 1935, Professor V.P. Vologdin and engineer B.N. Romanov conducted successful experiments on the use of high frequency currents (HFC) for induction surface hardening. The overwhelming success of this technology at tank factories during the Great Patriotic War was highly appreciated by the government of the USSR and in 1947 the All-Union Research Institute of High Frequency Currents (VNIITVCH) was created. The article discusses the organization of scientific research at the institute and at the department of Saint. Petersburg State Electrotechnical University (LETI), the features of the organization of the educational process, the achievements of recent years and promising areas of research on metal processing in an alternating electromagnetic field.

Optimal inductor design for surface hardening under conditions of interval uncertaity of process parameters

The paper is devoted to the optimal inductor design for surface hardening of steel cylindrical billets. The heating stage of surface induction hardening is considered as an object with distributed parameters, which unknowns are design characteristics of the induction installation. In real industrial conditions the main technological parameters are often defined by the intervals of their possible values. That is why, in the paper the optimal design problem under the conditions of interval uncertainty of initial billets temperature and thermal exchange coefficient is formulated. Solution of the formulated problem is carried out by alternance method of parametric optimization based on numerical model developed in Altair FLUX software.

Tribological characterization of potential crankshaft bearing steels for roller bearing engines

A crankshaft roller bearing internal combustion engine (ICE) offers a five percent or more improvement in overall engine efficiency and, thereby, a reduction in a five percent of CO2 emissions, compared to a plain bearing supported crankshaft. Current forged crankshaft steels represent the limiting factor of the rolling component, therefore, a replacement of the crankshaft steel is required. Apart from this, the tribology of the rolling contacts has been shown to be detrimental when lubricated with current engine oils. Therefore, this paper investigates the tribological performance of potential crankshaft bearing steels, i.e. DIN C56E2 (G55); DIN 50CrMo4 (G50); and DIN 100Cr6 (G3), while utilizing a state-of-the-art low viscosity 0W20 engine oil and under conditions prevalent to ICE. For this, damage mode investigation was performed in a disc-on-disc setup. Based on the results, wear damage of DIN 100Cr6 discs was shown to be dependent on the steel grade of which the counterpart disc was made from and surface hardness difference between both discs. In addition, surface fatigue and wear damage can be completely eliminated by selecting a proper surface roughness and hardness combination. Also, while under an elevated roughness level, engine oil was shown to promote both surface fatigue and wear damage through the work of ZDDP additives, which under extreme conditions can act as an extreme pressure (EP) additive. The residual stress measurements using the XRD technique revealed relatively high compressive residual stresses for G55 and G50 in comparison to G3 steel after surface induction hardening. In addition, no significant changes in residual stress for G55 and G50 were observed after the test. In contrast, relatively high tensile stress was observed for G3 near the surface region. This suggests that the most commonly used 100Cr6 bearing steel, in this case, is the most susceptible to surface fatigue.

Micro-pitting and wear characterization for different rolling bearing steels: Effect of hardness and heat treatments

The current trend of increased power density and reduction of oil viscosity in machine components is forcing engineers and scientists to engineer surfaces to endure higher contact pressures and stresses induced from rolling/sliding motion. Typically, surface-initiated rolling contact fatigue represents the main failure mode and has been gaining more and more attention lately. In this paper, the extent and morphology of the surface damage of different bearing steels in disc-on-disc contact under reduced lubrication conditions are studied. For this, rough-on-smooth contact was selected to promote surface fatigue damage on the smoother surface. Special attention was given to study both the effect of the hardness difference of the discs and the influence of different heat treatments, i.e. surface induction hardening (SIH) or through hardening (TH), on micro-pitting and wear performance. It was demonstrated through tribo-testing that the faster, rough surface undergoes only mild wear and plastic deformation of asperities. However, three different damage modes were observed and assessed on the slower, smoother surface, where the damage mode showed a strong dependence on a surface hardness difference between the smooth and the rough surface. Furthermore, it was observed that a plain medium carbon steel (DIN C56E2) showed better surface fatigue resistance than a low alloy high carbon steel (DIN 100Cr6) at similar surface hardness levels if SIH is applied on the former.

Investigations into series resonant inverter power control parameters for an effective metal induction surface hardening

Metal hardening depends on the material properties and the way the heat is being applied; therefore, a careful induction heating system parameter should be carefully selected, and in particular to meet the hardening requirements. In this study, a focus on a cost-effective design of the induction coil and the converter is presented. For that, a sample bar metal made of XC48 is considered. The methodology exploits an indirect procedure. It starts from the coil design according to the metal sample size, followed by a 2D finite element method for parameters and losses determination for the specified hardening depth. The power supply using resonant series converters is evaluated through electrical modelling simulation and which integrates a phase-locked loop scheme to account for load parameter variation. A comparison between the electrical and heat power is conducted to highlight the importance of the inverter control parameters leading to high efficiency and an appropriate and satisfactory hardening profile. A prototype system is built to demonstrate the effectiveness of the approach described.

Effects of Rapid Induction Heating on Transformations in 0.6% C Steels

Rapid induction surface hardening of high-carbon steel with an initial martensitic microstructure can attain the very high-strength levels needed for lightweighting components such as shafts, gears, and bearings that are subjected to high operating stresses. Specimens of pearlitic and martensitic 0.6 wt pct C steels were heat-treated using a dilatometer to investigate the effects of prior microstructure, heating rates (5 to 500 °C/s), and austenitizing temperatures (850 to 1050 °C) on the transformation to austenite and subsequent transformation to martensite during helium quenching. Specimens were quenched from selected temperatures during heating to assess the initial cementite precipitates formed in martensite before transformation to austenite. Other specimens were isothermally held at the austenitizing temperature to assess cementite dissolution rates and austenite grain evolution. Higher heating rates increased the Ac1 and Ac3 temperatures and lowered the Ms temperatures. Martensitic prior microstructures resulted in lower Ms temperatures and lower hardness as compared to a pearlitic prior microstructure. Alloy content and the austenitizing temperature (900 or 1150 °C) utilized to provide the initial martensitic microstructure also influenced the transformation temperatures and the amount of retained austenite.

Последние научные исследования в сфере электротермической металлургической обработки

A wide range of industrial metallurgical heating and melting processes are carried out using electrothermal technologies. The application of electrothermal processes offers many advantages from technological, ecological and economical point of view. Although the technology level of the electro heating and melting installations and processes used in the industry today is very high, there are still potentials for improvement and optimization due to the increasing complexity of the applications and the strong requirements regarding the performance and quality of the products but also regarding the reduction of time and costs for the development of new processes and technologies.In this paper recent applications and future development trends for efficient heating and melting by electrothermal technologies in metallurgical processes are described along selected examples like induction heating for forging or rolling of billets, heat treatment of strips and plates, press-hardening processes, induction surface hardening of complex geometries, induction welding as well as induction melting processes.

Experimental investigation and finite-element modeling of the short-time induction quench-and-temper process of AISI 4140

Abstract Induction hardening is a widely used surface treatment technique that has extensively been investigated. In contrast, induction tempering with short heating times ≤ 1 s has not been investigated thoroughly, nor by experiment neither by simulations. Also, the influence of rapid tempering on the residual stresses after induction surface hardening has only been investigated superficially. Induction quench and temper experiments were performed, both with heating times ≤ 1 s. A significant change of the residual stress state was observed, leading to a shift from compressive to tensile residual stresses in the surface layer. A multiphysical FE-model for the whole quench-and-temper process has been developed and validated. A good agreement with the experiments for the relevant mechanical properties hardness and residual stress could be achieved. The recently reported transformation induced plasticity during tempering has been found to play a key role in the development of residual stresses during tempering. The simulations further indicate that conventional heat treatment leads to more favorable residual stress states after tempering to a prescribed surface hardness. By accounting for tempering processes during austenitization, the hardening simulation could be generalized to different initial states and allows for the prediction of hardness minima in the transition zone.

Surface Induction Hardening of Steels: Process Modelling and Numerical Simulation

Heat treatments are widely used in industry to improve the surface behavior of components exposed to external mechanical actions and, therefore, undergoing wear phenomena. If compared to the conventional thermal treatments, induction hardening is an interesting candidate solution when the effect should be limited to the surface without affecting the microstructure and properties at the material core. Furthermore, this solution is appealing considering energy saving and cost reduction. In this process, an intense electric alternating current flows through a conductive coil enveloping the component to be treated. Such current generates a magnetic field and, as a consequence, eddy currents arise in the conductive work-piece providing a heat generation by the Joule effect. Due to this mechanism, the induction heating is characterized by faster heating rates with respect to the heating in a hot furnace. On the other hand, the induction hardening process requires a more challenging control of the operative parameters, namely the current density and frequency and the coil advancing speed. Numerical modeling and simulation are recognized as a very useful tool to predicting the effects induced by a treatment, avoiding undesired insufficient- or over-heating. The present work deals with a finite element numerical approach to the simulation of an induction hardening treatment of a steel component. The model is based on the subsequent solution of two numerical submodels. Firstly, the electro-magnetic field generated by the current flowing through a coil surrounding the processing part is inferred solving the Maxwell governing equations. Then, the magnetic field is used as input load for the subsequent heat transfer transient finite element model. The influence of the current density and frequency as well as other processing parameters on the magnetic and thermal fields is discussed.

RESEARCH ON SURFACE STRENGTHENING INDUCED BY ULTRASONIC PUNCHING TO IMPROVE MECHANICAL PROPERTIES AND CORROSION RESISTANCE FOR SHAFT PARTS

The shaft parts surface was treated by ultrasonic surface machining (USM) technology after surface induction hardening and tempering. In order to study the surface strengthening mechanism of ultrasonic punching on the surface of induction quenching and tempering, nano-intendation, X-ray diffraction, and scanning electron microscopy equipped with energy dispersive spectroscopy were utilized to evaluate the mechanical and corrosion properties of untreated and USM-treated surface. The results indicated that the surface treated by USM had an obviously gradient plastic deformation layer and the grain of lath martensite was refined by this deformation. The surface mircohardness of USM-treated sample had a gradient trend, and the surface highest hardness was increased. Surface residual stress of USM-treated specimen was higher than untreated surface. The surface of USM-treated specimen also exhibited a lower friction coefficient, and a smaller wear scar. In addition, the surface of USM-treated sample had better corrosion resistance than untreated surface.

Effects of induction hardened surface depth on the dynamic behavior of rotating shaft systems

AbstractRotating shaft systems play many critical roles in rotating machinery. The performance of any rotating machinery is very dependent on vibrations generated by the rotating shaft. The selection of rotating shaft material is very important to meeting the enormous demand of industrial users on the capability of vibration resistance in rotating machinery. Recent requirements for using rotating shafts have heightened the need for the materials used. The heat treatment of material has received much attention over the last few decades. The research to date has tended to focus on material properties for resistance and strength rather than on dynamic behavior. The main objective of the present study is to experimentally investigate the role of induction surface hardening which is one of the most commonly used types of heat treatment on AISI 1045 steel dynamic behavior. Heat treatable AISI 1045 steel is among the most widely used in all industrial applications requiring more resistance and strength. It has received much attention over the past several decades due to its usage in rotating shafts, axles, crankshafts, and spindles. Induction surface hardening is used to sustain service life by increasing the surface hardness and vibration reliability of a material. Since induction hardened surface depth plays a very important part in the stability of the rotating shaft, three different hardened surface depths (0.5, 1.0, and 1.5 mm) are utilized. The results show that a hardened surface depth of 1.0 mm surprisingly and positively affects the dynamic behavior of the rotating shaft as compared to the hardened surface depths of 0.5 and 1.5 mm.