共查询到19条相似文献,搜索用时 312 毫秒
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目的研究热和相变应变各自在渗碳淬火畸变中的作用,分析渗碳淬火工艺对齿轮合金钢畸变的影响。方法通过考虑相变和不考虑相变两种模型,对齿轮合金钢17CrNiMo6C形开口畸变试样渗碳淬火的畸变机理和变形过程进行数值模拟,并设计正交试验,量化工艺参数对畸变的影响程度,最后利用渗碳淬火实验测定表面含碳量和畸变量,验证分析结果。结果初始工艺下热应变约为相变应变的2倍。正交试验各工艺参数的F比结果从大到小顺序为:渗碳温度(1.74)、淬火温度(1.546)、碳势(1.448)、预热温度(0.603)和油温(0.473)。优化工艺参数为:渗碳温度880℃,淬火温度790℃,预热温度500℃,碳势0.8%,油温80℃。优化后畸变率减少了28.5%,畸变分析结果与实验结果对应较好。结论由热膨胀引起的热应变对试样的畸变占据主动,抵消并超过相变应变,渗碳温度、碳势和淬火温度对齿轮合金钢畸变影响较大。 相似文献
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动态淬火过程的流-固耦合数值模拟 总被引:1,自引:0,他引:1
借助流体动力学计算软件CFD2000,对介质不同流速下试样的淬火过程进行了流.固耦合数值模拟.将实测换热系数曲线数值化并线性插值,得到了不同温度、流速下的换热系数,并赋给流.固换热边界,从而实现流.固耦合计算,同时得到了淬火介质流场和试样温度场.数值模拟结果与实测结果的对比表明,用该数值方法来模拟淬火介质存在相变的复杂淬火过程是可行的,能够显示出淬火过程的蒸汽膜、沸腾换热、对流冷却三个阶段以及各自的特点.该方法可避免复杂气液两相流的计算,简化淬火过程流-固耦合计算. 相似文献
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采用有限元仿真和试验方法分析贝氏体等温淬火工艺对GCr15钢轴承套圈畸变和断裂韧性的影响。采用Deform-3D软件对轴承套圈贝氏体淬火工艺进行数值模拟。以圆柱滚子轴承NJ308为研究对象,仿真热处理后最大直径畸变量为0.08 mm,与试验结果对比,仿真误差14%。采用热处理工艺试验,测量贝氏体淬火后轴承直径畸变量为0.07 mm。对比测量分析常规马氏体淬火和贝氏体淬火后的畸变大小,贝氏体热处理后直径畸变极差小,更为均匀,有利于后续的磨削加工。通过断裂试验对比分析,常规的马氏体淬回火工艺断裂强度为113.3 kN,贝氏体等温淬火处理后的断裂强度为152.7 kN,断裂强度显著提升。 相似文献
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Evaluation of Important Factors Affecting Quench Distortion of Carburized Hypoid Gear with Shaft by Using Computer Simulation Methods 总被引:1,自引:0,他引:1
TsuyoshiSugimoto YouichiWatanabe 《材料热处理学报》2004,25(5):480-485
To minimize quenching distortion and dispersion, carburizing and quenching process conditions must be optimized; this includes the parts racking design used for quenching. We investigated some factors affecting carburized quenching distortion with an experiment using a hypoid gear having a shaft and with numerical simulation methods. The experimental results and those obtained from simulation were generally in agreement. Focusing on the surface temperature distribution in the gear, we studied quenching distortion characteristics in terms of changes in tooth profile and helix deviation. In our experiments, distortions occur during quenching in 373 K oil after austenitized temperature treatments conducted with various attitudes. We calculated the distortions by simulating the carburized oil-quenching process for the hypoid gear. Our results show large differences between the cooling rates of the tooth toe, middle section, and heel edges,and these greatly influence the change in tooth profile and helix deviation. We found that reducing the differences in temperatures on the gear surfaces during quenching is most important for minimizing the quench distortion of the hypoid gear. 相似文献
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螺旋伞齿从动轮渗碳淬火畸变及控制 总被引:1,自引:0,他引:1
对螺旋伞齿从动轮渗碳淬火后的畸变行为进行分析,指出热应力是其产生畸变的主要原因。通过改进装炉方式实现齿轮淬火过程中的均匀冷却,可显著减小齿轮的畸变。 相似文献
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Yingtao Zhang Wankai Shi Lin Yang Zhifei Gu Zhichao Li 《Journal of Materials Engineering and Performance》2016,25(7):2727-2735
The hardenability of gear steel is dependent on the composition of alloying elements and is one of important criteria to assess process of phase transformation. The variation of hardenability has to be considered in control of the microstructures and distortion during gear quenching. In this paper, the quantitative effect of hardenability has been investigated on phase transformations of spiral bevel gears in die quenching. The hardenability deviation of 22CrMoH steel was assessed by using Jominy test. The dilatometry experiments were conducted to build phase transformation kinetic models for steels with low and high hardenability, respectively. The complete die quenching process of spiral bevel gear was modeled to reveal the significant difference on microstructures and temperature history with variation of hardenability. The final microstructures of the gear are martensite in surface layer after quenching process. There are bainite inside the gear tooth and the mixture of bainite and ferrite inside gear for the gear with low hardenability. The microstructure is bainite inside the gear with high hardenability. 相似文献
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汽车同步器齿套在渗碳淬火后,发生变形,一般采用压淬整形等使同步器套失圆度减小,内花键尺寸稳定。本文着重分析了同步器齿套发生变形的原因及整形方法。通过实验验证了淬火时不均匀冷却是导致同步器齿套变形的主要原因,也是解决齿套变形的重要途径。 相似文献
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Yingtao Zhang Gang Wang Wankai Shi Lin Yang Zhichao Li 《Journal of Materials Engineering and Performance》2018,27(8):3803-3811
The strength of high-duty gears can be improved by carburizing and quenching processes. Quenching distortion is inevitable during the process, and it has direct effects on the precision of the gear. For spiral bevel gear with big diameter and small thickness, die quenching process is applied in the manufacturing to control the distortion in axial direction. Die quenching parameters must be optimized to minimize the distortion while considering non-uniformity of chemical compositions and loads. In this paper, material models of gear material (22CrMoH) built based on the phase transformation kinetics, static mechanical properties and phase transformation plasticity equations. Finite element analysis (FEA) models are conducted to study the whole die quenching process based on the production process. Die quenching experiments and testing of microstructures and distortions are conducted to verify the accuracy of the FEA models. The effects of loads and bottom die obliquity on the final distortion are studied to set the appropriate range and control distortion. The distortion was very sensitive to the bottom die obliquity and some part of load ranges. The distortion changes little when the load of inner die was in the range of 1.38-2.07 MPa and the load of outer die was in the range of 2.07-2.76 MPa. The distortion range is fitted the production requirements by setting the inclination angle of bottom die between 0.12° and 0.29°. 相似文献
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在生产中,齿轮和齿轮轴的渗碳和淬火畸变是难以避免的,减小其畸变量是一个技术难题.然而,大量的实测数据表明,齿轮和齿轮轴的渗碳和淬火畸变是有规律的,如果冷热加工工艺合理,这种畸变量可以控制在要求的范围内. 相似文献
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邢大志 《热处理技术与装备》2008,29(1):57-59
根据热处理产生形变的普遍规律分析,正火与调质所产生的残余应力不同,其产生形变的规律也不同.对于大型渗碳淬火齿圈,预处理采用调质与正火进行比较,调质可以得到更加均匀分布的碳化物形态,其形变规律与最终的渗碳淬火形变规律一致,更有利于减小零件的热处理畸变. 相似文献