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连铸恒温出坯是实现连铸直轧的有效手段,为了实现圆坯恒温出坯的目的,依据感应加热原理提出在连铸坯切割段变功率感应加热恒温出坯的方法,通过数值模拟研究了恒温出坯方法的可行性。研究发现,通有交流电的感应线圈在铸坯内部产生磁场和感应电流,上述物理场主要集中在铸坯表面。此外,感应电流产生的焦耳热对连铸坯起到均温作用,均温效果随着电流频率或铸坯移速的增大先增强后减弱。研究表明,变功率感应加热实现圆坯连铸恒温出坯的方案是可行的。为了优化感应加热功率,建立了感应线圈加热功率计算模型。根据感应线圈加热功率计算模型,实现恒温出坯的加热功率与连铸坯几何尺寸、物性参数、初始温度、运动速度和线圈长度密切相关。 相似文献
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强力感应器与导磁体的发展 总被引:9,自引:4,他引:5
裸感应器装上导磁体能提高感应器的效率,集中能量到所需加热零件的表面,称之为强力感应器。本文叙述了强力感应器提高效率的有关数据与各种导磁体的性能与其发展。 相似文献
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利用Comsol软件对30CrMnSiNi2A钢的感应回火进行了模拟,利用控制变量法研究了感应加热过程中电源频率、电流以及线圈的结构和尺寸参数对工件内部温度均匀性的影响。结果表明,电流强度和电源频率越大,工件在感应加热过程中的升温速率越大,最终平衡温度越高,但其径向/轴向温差越大。线圈的匝数越多,工件的升温速率和径向/轴向温差越大,最终平衡温度越高。线圈半径的变化仅会对工件端部的升温速率产生影响,线圈半径越小,工件端部的升温速率越快,轴向温差越小。线圈截面外径和壁厚的变化对工件感应加热过程中的温度场没有影响。根据模拟结果的对比分析,提出了一种采用分段加热法与增设导磁体相结合的方法,对感应回火系统进行了优化。通过优化设计可使工件在感应加热过程中的径向温差基本消除,使轴向温差小于10℃。 相似文献
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Finite-element simulation of moving induction heat treatment 总被引:1,自引:0,他引:1
K. F. Wang S. Chandrasekar H. T. Y. Yang 《Journal of Materials Engineering and Performance》1995,4(4):460-473
An efficient finite-element procedure with a remesh scheme has been developed for the analysis of the moving induction heat
treatment process, wherein relative motion occurs between the coil and the workpiece. In this procedure, the magnetic field
is first simulated by using an updated mesh that tracks the moving coil position; the moving heat source within the workpiece
material is derived from the magnetic field. The heat equation is then solved to obtain the temperature field created by the
heat source. The procedure has been applied to calculate the temperature distributions in 1080 carbon steel cylinders during
induction heating. The calculations have been validated by comparison with analytical solutions for the temperature distribution
obtained using Green’s function methods. Finally, the temperature, residual stress, and microstructure distributions in quenched
1080 steel cylinders have been obtained using the finite-element procedure. Quenching of the heated cylinders, by both a moving
cooling ring and a stationary liquid bath, has been analyzed. The finite-element procedure presented incorporates temperature-dependent
material properties, phase transformations occurring in the 1080 steel, the change in magnetic permeability of the 1080 steel
at the Curie temperature, and an elastoplastic stress model based on a mixed hardening rule. The simulation results demonstrate
that the finite-element procedure could be applied to a variety of moving induction heat treatment problems to determine the
residual stress and microstructure distributions in the heat-treated component. It also could be used in the design of process
parameters and coils. 相似文献
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Noureddine Barka Ahmed Chebak Abderrazak El Ouafi Mohammad Jahazi Abdellah Menou 《Journal of Materials Engineering and Performance》2014,23(9):3092-3099
The beneficial effects of using flux concentrators during induction heat treatment process of spur gears made of 4340 high strength steel is demonstrated using 3D finite element model. The model is developed by coupling electromagnetic field and heat transfer equations and simulated by using Comsol software. Based on an adequate formulation and taking into account material properties and process parameters, the model allows calculating temperature distribution in the gear tooth. A new approach is proposed to reduce the electromagnetic edge effect in the gear teeth which allows achieving optimum hardness profile after induction heat treatment. In the proposed method, the principal gear is positioned in sandwich between two other gears having the same geometry that act as flux concentrators. The gap between the gear and the flux concentrators was optimized by studying temperature variation between the tip and root regions of gear teeth. Using the proposed model, it was possible identifying processing conditions that allow for quasi-uniform final temperature profile in the medium and high frequency conditions during induction hardening of spur gears. 相似文献
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Finite-element simulation of induction heat treatment 总被引:2,自引:0,他引:2
K. F. Wang S. Chandrasekar Henry T. Y. Yang 《Journal of Materials Engineering and Performance》1992,1(1):97-112
An efficient finite-element procedure has been developed for the analysis of induction heat treatment problems involving nonisothermal
phase changes. The finite-element procedure first simulates the magnetic field developed when currents flow through an induction
coil by solving Maxwell’s electromagnetic field equations; at the following step, it calculates the temperature distribution
in the workpiece due to eddy currents induced by the magnetic field. The final stage of the simulation involves the determination
of the distributions of residual stress, hardness, and microstructure in the workpiece. The finite-element analysis includes
temperature-dependent material properties, changes in permeability of the workpiece at the Curie temperature, a mixed hardening
rule to describe the material constitutive model, and the incorporation of time-temperature-transformation (TTT) diagram. The procedure was applied to the simulation of the induction hardening of 1080 steel bar. Firstly, the magnetic
field and temperatures developed in the workpiece during (a) the induction heating of an infinitely long 1080 steel cylinder
by a single encircling coil and (b) the induction heating of a semi-infinite half-space by a single coil suspended above it
were calculated using the finite-element procedures. These were validated by comparing them with analytical solutions derived
for these configurations using a Green’s function method. Finally, to demonstrate the predictive capability and practical
applicability of the current finite-element procedure, two examples pertaining to the induction heat treatment of an infinite
1080 steel bar of square cross section and a notched finite 1080 steel cylinder of circular cross section were analyzed to
predict the magnetic field, temperature, and residual stress distributions. The current finite-element procedure could be
used as a powerful design tool for linking induction heat treating parameters with the mechanical property attributes of the
heat treated component. 相似文献
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J. Yuan J. Kang Y. Rong R. D. SissonJr. 《Journal of Materials Engineering and Performance》2003,12(5):589-596
A modeling system for analyzing the integrated induction hardening processes was developed based on a general-purpose finite
element program, with the capability to analyze the whole process from electromagnetic-induced thermal heating to final hardening.
A coupled electromagnetic-thermal model was applied to study the induction heating process, which includes consideration of
nonlinear material characteristics on temperature. Also, arrangement of AC current density distribution was conducted to simulate
practical induction coil structure and magnetic concentrator effects to achieve desired heating patterns for later quenching
and hardening analysis. Quenching analysis can provide cooling curve at any location in a heat-treated workpiece based on
heat transfer principles. In hardening analysis, phase transformation was studied and an algorithm was developed to determine
volumetric content of micro-structural constituents formed from austenitized phase in quenching process, based on analysis
of the interaction between cooling curve and material time-temperature-transformation (TTT) diagram. Finally, hardness value
was converted from martensite content based on a developed formulation. Validation was preliminary conducted based on comparison
of hardening pattern of induction hardening of an automotive spindle with complex surface. 相似文献
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内置线圈发热会影响磁流变液黏度,并且线圈内置会导致安装、拆卸不易。为解决以上问题,研究线圈外置式磁流变液减震器的结构设计;通过仿真分析不同的缸体材料、线圈布置方式和结构参数对间隙处磁感应强度的影响。结果表明:间隙处的磁感应强度随着电流的增加而逐渐增大,但是受材料磁饱和强度的影响,不能无限增加;线圈外置式磁流变液减震器要使用槽宽尽可能大的单线圈模型;随着间隙的不断增加,间隙处的磁感应强度不断减小。 相似文献
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旋转超声波加工设备可以采用非接触电能传输耦合器为高速旋转的超声振子提供电能,以取代传统的接触式碳刷滑环,这种非接触电能传输方式安全、稳定,且对转速没有限制。但由于主次级磁芯之间存在间隙,使其漏磁通较大,功率传输能力较低。为提高非接触旋转耦合器的功率传输能力,采用有限元仿真和实验的方法,通过对比分析不同材质及结构形式耦合器的磁通分布情况、线圈自感、线圈间互感、耦合系数、线圈交流电阻等参数,对耦合器进行了优化设计。优化后的非接触旋转耦合器具有更高的耦合能力及功率传输能力。 相似文献
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加热参数对表面温度信号的影响的建模与分析 总被引:1,自引:0,他引:1
为了研究加热参数(包括加热时间、热流密度和加热量)对表面温度信号的影响,使用有限元法对二维和三维模型进行了仿真分析,得出了以下结论:有缺陷区与无缺陷区的最大温差主要受加热量的影响,随加热量的增加而增大;最大温度对比度及其出现时间和有缺陷区与无缺陷区的最大温差出现时间对热流密度的改变不敏感,但是会受到加热时间的影响;对于碳纤维增强塑料,最大温度对比度表现出较强的稳定性,说明该参数更能够反映出缺陷本身的特征,有助于缺陷的定量计算;对于铝类热扩散率高的材料,高热流密度和短时加热是一种更为合适的加热方式。 相似文献
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三维点式感应淬火电磁热耦合场数值模拟 总被引:1,自引:0,他引:1
针对45钢三维点式感应淬火工艺进行参数设计,建立点式感应淬火过程的电磁场及温度场的非线性偏微分方程组,在有限元软件ANSYS中使用耦合场分析的方法实现了对加热功率为36 kW,电流频率为50 kHz的感应热处理工艺的数值模拟.结果表明,在综合考虑表面组织完全奥氏体化及感应加热效率的情况下,该工艺的最佳加热时间约为2 s.通过模拟分别得到使用冷却水和冷却油作为冷却介质时的感应淬火过程中的温度变化规律,结合45钢的连续冷却转变曲线,以马氏体转变临界冷却速度为判断依据,对淬火后工件表面组织进行预测,结果表明两种淬火条件均可以实现表面组织马氏体转变,实现工件的表面强化,且淬硬深度均约为1.0 mm. 相似文献
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Chen Ruirun Yang Jieren Ding Hongsheng Huang Feng Su Yanqing Guo Jingjie and Fu Hengzhi 《中国铸造》2012,(1):15-19
Bottomless electromagnetic cold crucible is a new apparatus for continuous melting and directional solidification;however,improving its power efficiency and optimizing the configuration are important for experiment and production.In this study,a 3-D finite element (FE) method based on experimental verification was applied to calculate the magnetic flux density (Bz).The effects of the power parameters and the induction coil on the magnetic field distribution in the cold crucible were investigated.The results show that higher current intensity and lower frequency are beneficial to the increase of Bz at both the segment midpoint and the slit location.The induction coil with racetrack section can induce greater Bz,and a larger gap between the induction coil and the shield ring increases Bz.The mechanism for this effect is also discussed. 相似文献
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Wenyong Luo Liang HuangJianjun Li Xianlong LiuZhiqiang Wang 《Journal of Materials Processing Technology》2014,214(11):2811-2819
A driving coil is one significant tool for transferring electrical energy to plastic energy during electromagnetic forming, and the coil structure plays a crucial role on the distribution of magnetic field and electromagnetic force acting on the workpiece and determines the forming characteristics and magnitude. Due to the limitation of the conventional coil on forming a large and thick-walled component, this paper proposes a novel multi-layer flat spiral coil for large and thick sheets based on theoretical analysis of the relations of coil inductance, skin depth of sheets and energy efficiency. Taking electromagnetic flanging forming of a large and thick-walled sheet for example, a 3D numerical model is developed to investigate the effects of coil structure on magnetic field and sheet forming. Finally, several electromagnetic flanging experiments with 5 mm 5056 aluminum alloy sheets by a three-layer coil are carried out to validate the simulation results and a comparison of the thickness distribution and the fittability degree between the die and the sheet after one-time and two-time forming is performed. The results show that the magnetic force loading on the workpiece increases obviously with the increase of the coil layer owing to the additive effect of each layer of the multi-layer coils, and further enlarges the deformation, while the pressure acting on the coils can be controlled effectively due to the share of each layer of the multi-layer coils. The energy efficiency of the multi-layer coils increases with the increase of the skin depth and peaks at 19.6% when the skin depth is equal to the sheet thickness. The experimental results of electromagnetic flanging based on a three-layer coil coincide with the simulation results. 相似文献
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对于镁合金带内筋筒形件的热强旋成形,旋前管坯的温度场分布对成形过程中的材料流动及旋压件的成形质量具有重要影响。基于多物理场耦合软件COMSOL,建立了ZK61镁合金带内筋筒形件热强旋旋前管坯电磁感应加热模型,模拟分析了不同感应加热参数条件下管坯温度场的分布情况,并通过实验验证了模型的可靠性。研究结果表明:相比电流强度,电流频率对管坯表心温差的影响更为显著,随着电流频率及电流强度的增加,管坯表心温差均逐渐增大;感应线圈的匝数及线圈与管坯的间距对管坯表心温差的影响较大,随着线圈匝数的增大,管坯表心温差近似呈指数形式增加,线圈与管坯的间距越大,管坯表心温差越小。 相似文献