Heat Treatment Of Gears Research Articles

Optimization Method for Gear Heat Treatment Process Oriented to Deformation and Surface Collaborative Control

Optimization Method for Gear Heat Treatment Process Oriented to Deformation and Surface Collaborative Control

Choice of technology for heat treatment of large diameter gears on the basis of the system-resource approach

The article solves the problem of choosing a technology for heat treatment of gears of large diameter based on a system-resource approach for a particular enterprise. To solve the problem, a functional model was developed, the production resources available to the enterprise were analyzed, and the possibilities of developing solutions using system forecasting models were analyzed. Sketches of the solution were developed for transfer to the departments of mechanization and automation for further design and technological development and manufacturing.

Effects of Heat Treatment Techniques on the Fatigue Behaviour of Steel Gears: A Review

Heat treatment of gears are fundamental to efficient and reliable gear production because of its contribution to the overall cost of manufacturing. Different heat treatment techniques are targeted to improving hardness, ductility and strength to minimize material degradation or wear. However, several heat treatment methods had led to gear tooth distortion such as shrinkage of tooth thickness which eventually affects the contact angle. The study therefore focused on some selected heat treatment on gears and their effects on gear applications. from the reviewed heat treatment techniques, distortion is a common occurrence that result to gear fatigue. Also, it was noted that most times, the medium for quenching and most importantly, variation in the concentration affects the gear accuracy. Thus, local fracture and material loss ensue. Nevertheless, the study further suggested the use of empirical model and simulation approach for stress prediction.

Effects of Heat Treatment Techniques on the Fatigue Behaviour of Steel Gears: A Review

Heat treatment of gears are fundamental to efficient and reliable gear production because of its contribution to the overall cost of manufacturing. Different heat treatment techniques are targeted to improving hardness, ductility and strength to minimize material degradation or wear. However, several heat treatment methods had led to gear tooth distortion such as shrinkage of tooth thickness which eventually affects the contact angle. The study therefore focused on some selected heat treatment on gears and their effects on gear applications. from the reviewed heat treatment techniques, distortion is a common occurrence that result to gear fatigue. Also, it was noted that most times, the medium for quenching and most importantly, variation in the concentration affects the gear accuracy. Thus, local fracture and material loss ensue. Nevertheless, the study further suggested the use of empirical model and simulation approach for stress prediction.

ELTA 7.0 program for induction heat treatment of gears

ELTA 7.0 program for induction heat treatment of gears

ELTA 7.0 program for induction heat treatment of gears

Induction heat treatment of gear is a very complicated technology and needs to be investigated in detail. A great deal of researches using experimental methods and 3D computer simulation has been carried out to obtain required mechanical properties of steel. In order to perform these tasks more efficiently the authors offered to use a new version of ELectro-thermal analysis (ELTA) with a special Gear Application. An idea of 2D gear model, methods and structure of program is described. ELTA 7.0 can calculate integral parameters of inductor and temperature in the cross-section of gear for heating and cooling stages simpler and faster than in the case of 3D simulation. Several examples of induction hardening with single and double variable frequencies of power source are presented.

Load capacity simulation of an agricultural gear reducer by surface heat treatment

Gear reducers are widely used for various agricultural machinery applications such as greenhouses, tractors, and agricultural vehicles. However, thermal deformation and surface pitting at gear tooth flank frequently occur in gear reducers due to high torque. Thus, surface heat treatment of gears is required to improve wear and fatigue resistance. The objective of this study was to simulate the load capacity of the agricultural gear reducer. The simulation was performed for the following three surface heat treatment methods: untreated gears, nitriding heat treatment, and induction hardening method, those mostly used for agricultural gear reducers. The load capacity of the gear reducer was simulated using the safety factor, limit bending stress, and limit contact stress of the gear. The simulation of the load capacity was conducted using KISSsoft commercial software for gear analysis. The main results of simulation test were as follows: first, the nitriding heat treatment resulted in the highest safety factor for bending stress, which was increased about 77% from those of the untreated gears. Second, the induction hardening was the highest safety factor for contact stress, which was increased about 150% from those of the untreated gears. The safety factor for contact stress of the induction hardening was increased about 64% from those of the nitriding heat treatment. The study result suggested that the surface heat treatments could enhance load capacity and that the method of surface heat treatment should be determined based on simulation results for appropriate use scenarios.

Investigation of Heat Treatment of Gears Using a Simultaneous Dual Frequency Induction Heating Method

A heat treatment of gears (increasing hardness in the surface layers of gear teeth) significantly enhances the quality and performance of gears in terms of resistance to ware and abrasion and fatigue strength. Recently, a simultaneous dual frequency (SDF) induction heating technology has emerged as the most effective and efficient heat treatment method. It strives to achieve “uniform” temperature distributions along the outer contour of gears by applying two input currents simultaneously [1, 2]. The amplitude and frequency of both currents are regulated independently to control the hardening depth at the root and the tip of the gear teeth [3]. Obtaining the best combinations of the input frequencies and powers experimentally is very costly and time consuming. Thus, many researches have been concentrated on determining these parameters using simulation methods, but they require tremendous computational time and resources [4, 5]. In an effort to reduce computational costs in determining SDF input parameters, this paper proposes a 2D FE modeling method, and it experimentally evaluates the heat treatments of gears using a SDF induction heating system with the parameters obtained with 2D FE analysis.

동시 이중주파수를 이용한 기어 열처리의 열·전자기 연성 해석

In this paper, Finite Element Analysis (FEA) for gear heat treatment using simultaneous dual frequency (SDF) induction heating is conducted. To do this, thermal-electromagnetic coupled FE model is built. A two dimensional FE model of gear and heater is introduced to reduce computation time. For more time-efficient analysis, harmonic analysis for electromagnetic model is adopted and transient analysis model, for heat transfer model. Through the coupled analysis, it can be found that the proposed FE model can solve for SDF induction heating of gear and heat treatment parameters can also be determined.

Simulation Analysis on Hobbing Process and Heat Treatment of Automotive Transmission Gear Based on the MASTA Software

Based on the MASTA cylindrical gear manufacturing module, the hobbing process and heat treatment of automotive transmission gear were simulated. The simulation results show that the hobbing process has a lot of excellent process characteristics, such as good adaptability, continuous cutting, no extra stroke, higher productivity. By the MASTA software simulation the maximum value of the gear heat treatment deformation is about 70 um. The trend of thermal deformation first increases, then decreases, and then increases.

Gear Application Feasibility Study of Functionally Gradient Material

The problems of the tooth root bending stress increase,distortion, the life of the gear reduction and other issues existing in the gear heat treatment process, In order to solve these problems, functionally gradient material (FGM) was used on gear working surface. the analysis of heat treated gear performance and common gear performance comparison analysis has maded; A functionally gradient material cylindrical involute gear model and a common cylindrical involute gear model were created, Then finite element calculation of bending stress and analysis of the two models has maded. The FGM gear have better performance on the root bending stress and the hardness of the working surface, and also can avoid disadvantages about distortion and uniform carburized layer which might happened in heat treatment process. The experimental results show that FGM can be used on gear.

ICME Tools Can Help Control Gear Distortion from Heat Treating

Abstract Engineers at the Ford Motor Co. are using integrated computational materials engineering (ICME) tools, allowing them to accurately simulate the heat treatment of gears and predict phase transformation kinetics and distortion.

Gear Heat Treatment for Toughening Up Your Teeth

Gear Heat Treatment for Toughening Up Your Teeth

Computer modeling and validations of steel gear heat treatment processes using commercial software DANTE

The heat treatment process of a gear made of AISI 9310 carburized steel is modeled using the commercial heat treatment simulation software DANTE. Both carburization and quenching processes affect the residual stress distribution and distortion of heat-treated parts, which are important to service quality and fatigue life. DANTE/VCARB is used to design the boost/diffuse schedule of a vacuum carburization process. Oil quenching is modeled following the vacuum carburization process. Thermal gradient and phase transformation are two main sources of distortion and residual stresses in quenched parts. The relation of the carbon distribution, thermal gradient, and phase transformations during quenching is studied through the gear modeling example. Because of geometry, the residual stress distribution after quenching is non-uniform along the gear surface. In general, the root fillet has higher residual compression than either the root or tooth face locations after traditional oil quenching of carburized gears. The predicted residual stresses from the oil quenching model are imported into a single tooth fatigue bending model. The gear stresses under bending load indicate the possible cracking locations during the bending fatigue test. The importance of heat treatment residual stresses during gear design is pointed out, and it is commonly ignored in the gear design and manufacturing industry.

Simulation of carburizing-quenching of a gear. Effect of carbon content on residual stresses and distortion

Predictions of deformation, residual stresses and hardness after heat treatment of gears by numerical simulation are very useful to determine optimum condition to decrease the distortion of machinery parts. In this paper, simulation on carburizing quenching of a helical gear made of carbon steel SCr420 was carried out using three-dimensional coupled analysis based on thermo-mechanical theory considering phase transformation. The expansion and latent heat due to phase transformation at various carburizing conditions were measured by TMA and DSC to determine the thermal physical properties of SCr420 carbon steel. The influence of the transformation plasticity strain on deformation, residual stress and hardness of a gear was clarified in the simulation. The accuracy of simulation also is verified by the comparison between the experimental data and the simulated result of the distortion and residual stress. From the predicted results, improvement of the hardness and strength on surface of the gear due to the carburizing-quenching process can be verified.

Chemicothermal treatment of gears in fluidized bed

1. The fatigue and static strengths of steel 12KhN3A after carburizing and tempering in fluidized bed are the same as those resulting from the existing treatment, while the wear resistance is higher. 2. Rapid heat treatment of gears in fluidized bed (carburizing to a depth of 1.2–1.3 mm at 950° for 2.5 h; high-temperature tempering at 650° for 3 h; quenching from 820°, with holding for 20 min; lowtemperature tempering at 170° for 2 h) is recommended for production tests. 3. As compared with the existing technique, treatment in fluidized bed shortens the carburizing time and reduces the quenching time by a factor of four and tempering time by a factor of three.