共查询到18条相似文献,搜索用时 468 毫秒
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激光相变硬化在模具表面强化中的应用研究 总被引:5,自引:0,他引:5
介绍了激光表面相变硬化加工的特点及应用、材料表面激光相变硬化工艺的研究——激光相变硬化机制、激光相变硬化层的影响因素、激光相变硬化过程的温度场研究、激光相变硬化后残余应力场的研究以及激光相变硬化在模具表面强化中的应用。 相似文献
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主要介绍了激光相变硬化的特点及强化机理、激光表面相变硬化工艺。分析了钢铁材料激光相变硬化后的组织与性能,及近年来激光相变硬化技术在材料科学领域的研究状况。 相似文献
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主要介绍了激光相变硬化的特点及强化机理、激光表面相变硬化工艺。分析了钢铁材料激光相变硬化后的组织与性能。及近年来激光相变硬化技术在材料科学领域的研究状况。 相似文献
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激光表面硬化的特点及在齿轮和模具中的应用优势 总被引:2,自引:0,他引:2
本文简要介绍了激光表面硬化的原理、特点、工艺参数、装置系统和经激光表面硬化后金属材料的组织与性能。以激光相变硬化在齿轮和模具中的应用为例表明,采用激光硬化可显著地提高材料的使用性能和寿命。 相似文献
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模具钢激光表面热处理现状 总被引:6,自引:0,他引:6
激光表面热处理是70年代千瓦级大功率激光器出现以后发展起来的应用技术。激光表面热处理大致上可以分为两类,即表面不熔化的激光热处理和表面熔化的激光热处理。前者主要指激光淬火(即激光相变硬化)、激光退火、激光冲击硬化等;后者包括激光熔凝硬化(又称激光晶粒细化硬化)、激光上釉(又称激光非晶化)、激光合金化、激光涂覆等。激光熔凝硬化和上釉表面无化学成分变化,激光合金化和涂覆表面化学成分发生变化。 相似文献
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通过建立试件的热分析模型,对激光模具表面非熔凝加工过程进行了有限元分析,从而对激光相变硬化过程中的温度场、残余热应力、应变场进行了研究。通过计算机模拟,获得指导性工艺参数,并对试件进行激光强化试验,将计算值与试验值进行耦合,从而获得最佳工艺参数,提高模具的使用寿命。 相似文献
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This paper deals with the optimization of process parameters for maximum productivity (given by the product of scanning velocity and cross feed) in laser transformation hardening. The process parameters considered are laser beam power, P; laser beam diameter, Db; and the heat intensity distribution, namely, normal, bimodal, or uniform. A thermal analysis of the laser surface transformation hardening of gears was conducted (based on Jaeger’s classical moving heat source method) by considering the laser beam as a moving plane (disc) heat source to establish the temperature rise distribution in the workpiece (gear) of finite width. In a recent investigation [Int. J. Heat Mass Transfer 44 (2001) 2845], the authors considered the case of a heat source with a pseudo-Gaussian (or normal) distribution of heat intensity. The analytical results were compared with the experimental results published in the literature. In laser heat treatment of steel, it is generally considered preferable to use a wider heat intensity distribution, such as uniform or bimodal, for it enables more uniform case hardening depth. In this paper, this model is extended to cover bimodal and uniform distributions and compared with the normal distribution. Scanning velocities for no surface melting and for a case hardening depth of 0.1 mm were determined for surface transformation hardening of AISI 1036 (EN 8) steel for a range of laser beam powers, P, laser beam diameters, Db, and various heat intensity distributions. Since diffusion during the heat treatment (surface transformation hardening) process is a time dependent phenomenon, based on the literature review, an interaction time of 15 ms was taken as a basis. It is hoped that laser industry with adequate facilities available can validate the thermal analysis and subsequent optimization presented in this paper. 相似文献
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CALCULATION OF 3-D TRANSIENT TEMPERATURE FIELD DURING LASER TRANSFORMATION HARDENING PROCESS 总被引:4,自引:0,他引:4
L. W Zhang R.S. Wang J. Th.M.De Hosson Y.L. Xia F. G. Wang ) The State Key Lab. for Materials Modification by Laser Ion Electron Beams Dalian University of Technology Dalian China ) Department of Applied Physics University of Gro 《金属学报(英文版)》2000,13(2):806-810
1.IntroductionLasertransformationhardeningprocessisathreedimensiontransientheattransferproblemwhichinvolvesinphajsetransformation,heatconduction,heatconvectionandheatradiation.Thecalculationoftemperaturefieldoflasertransformationhardeningprocessisaprerequisitetotheoptimizationofparametersoflasertransformationhardening.Thisworkstartedintheearlyof1970',uptonow,alotofmodelsandcalculationmethodswereproposedtocalculatethetemperaturefieldoflasertransformationhardeningprocessll--gi.Allthesemodelsareb… 相似文献
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A mechanical model of a laser transformation hardening specimen with a crack in the middle of the hardened layer is developed to quantify the effects of the residual stress and hardness gradient on crack driving force in terms of J-integral. It is assumed that the crack in the middle of the hardened layer is created after laser transformation hardening. Using a Double Cantilever Beam model, the analytic solutions, which can be used to quantify the effects of the residual stress and the hardness gradient resulting from laser transformation hardening on crack driving force, are obtained. A numerical example shows the crack driving force decrease is very sensitive to the residual compressive stress increase. 相似文献
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Predictive modeling of laser hardening of AISI5150H steels 总被引:2,自引:0,他引:2
This paper presents accurate predictive modeling of the laser hardening process in terms of laser operating parameters and initial microstructure without the need of any experimental data. The model provides the diagrams that are useful for predicting hardness profiles, optimizing practical process parameters and assessing the potential of laser hardening for different steels. It is shown that the hardness and depth of the hardened layer in hypoeutectoid steels (carbon wt%<1) could be predicted from this model with good accuracy.The model combines a three-dimensional transient numerical solution for a rotating cylinder undergoing laser heating by a translating laser beam with a kinetic model describing pearlite dissolution, carbon redistribution in austenite and subsequent transformation to martensite by utilizing the feedback from the CCT diagram. In order to validate the thermal model and assert the accuracy of temperature predictions the temperature was measured using an infrared camera and a good agreement between the predicted and measured temperatures is shown. Results are presented as processing maps, which show how the case depth and hardness depend on input operating parameters. The good agreement between the measured and predicted hardness profiles ascertains the accuracy of the thermal-kinetic model developed for AISI5150H steels. 相似文献