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基于ABAQUS软件建立了42CrMo锻钢活塞外圆精车加工的二维切削仿真模型,采用单因素法研究了切削参数对残余应力的影响规律.结果 表明:42CrMo钢精车加工过程中,热应力引起的残余拉应力起主导作用,已加工表面产生残余拉应力并沿深度方向迅速转变为压应力.残余应力层深度随进给量和背吃刀量的增大而增大,切削速度对残余应力层深度影响不显著.表面残余拉应力随切削速度和进给量的增大而增大,背吃刀量对表面残余应力影响不显著.最大残余拉应力出现在工件已加工表面以下,表面残余应力、最大残余拉应力和最大残余压应力随切削参数的变化趋势与切削温度随切削参数的变化趋势基本一致. 相似文献
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运用有限元软件AdvantEdge对7050铝合金材料进行了切削加工仿真模拟,采用单一变量法得到了工件表面残余应力与切削温度随切削参数改变而发生变化的规律。结果表明:工件表层为残余压应力,亚表层为残余拉应力,切削参数对最大残余应力所在深度影响较小,进给量对工件表面的残余应力影响最大,切削速度次之,背吃刀量最小,切削温度随着切削参数的改变也呈现出一定的规律。 相似文献
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车铣加工表面残余应力的研究 总被引:2,自引:0,他引:2
金属切削用量对工件的表面残余应力有着重要的影响.通过单因素正交车铣残余应力实验,研究了车铣加工65#钢时,分别改变切削速度vc和轴向进给量fa两个切削用量对已加工件表面残余应力的影响规律,并进行了理论分析.同时对比了车铣加工与一般车削加工的残余应力状态.研究结果表明随着切削速度vc的提高,工件表面残余拉应力随之增大,但当切削速度vc超过188.4 m/min时,工件表面残余拉应力急剧减小出现压应力;增大轴向进给量fa,工件表面残余压应力减小. 相似文献
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准确预测残余应力对提高微小工件的可靠性非常重要.建立微切削残余应力的理论分析预测模型,应用有限元仿真方法,探求了不同切削速度和进给量下微切削45钢已加工表面残余应力分布规律,分析了切削速度和进给量对已加工表面残余应力的影响,为优化微切削过程和防止微小零件疲劳破坏提供可靠的依据. 相似文献
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切削用量对钛合金已加工表面残余应力的影响 总被引:1,自引:0,他引:1
《工具技术》2013,(10):33-37
为了得到切削用量对钛合金加工表面残余应力的影响,本文根据金属切削有限元分析相关理论,建立了三维斜角切削有限元模型,对钛合金Ti6Al4V的铣削加工进行了模拟分析,得到了切削速度和切削深度对工件加工表面残余应力的影响。由模拟结果得出:残余应力随切削速度的增大而逐渐增加,切削速度对加工表面残余应力的影响较大,同时随着切削速度的改变,表面残余应力层的厚度有上升趋势;残余应力在已加工表面外表面表现为拉应力,沿深度方向由拉应力逐渐过渡到压应力;切削深度对残余应力及残余应力层的影响都较小。 相似文献
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试验研究了不同速度下Al_2O_3/(W,Ti) C陶瓷刀具的磨损寿命以及不同后刀面磨损量时对应的切削温度,不同切削速度时刀具后刀面磨损量对表面粗糙度、表面残余应力以及加工硬化等表面完整性的影响规律及机制。结果表明:随着切削速度提高,工件已加工表面粗糙度减小;随着陶瓷刀具后刀面磨损量增加,表面粗糙度先减小后增大;已加工表面的残余压应力随切削速度增大而逐渐减小;表面残余应力随后刀面磨损量增大从残余压应力向残余拉应力转变;随着切削速度的提高,工件表面加工硬化逐渐降低;已加工表面显微硬度值和硬化层深度随后刀面磨损量增加而增大。 相似文献
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采用JobnSOn—Cook失效准则,建立了钛合金的二维正交切削热一机械应力耦合有限元仿真模型,分析计算了不同切削条件下已加工表面残余应力的分布规律。结果表明:已加工表面层残余应力为拉应力,沿着深度方向由拉应力逐渐过渡到压应力。表面残余应力随着切削速度的增大而增大,在一定的前角变化范围内,随着刀具前角的增大,表面残余拉应力先增大后减小,而随着刀具后角的增大却减小。各加工参数对残余应力层的厚度影响都很小。 相似文献
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H13淬硬模具钢精车过程的数值模拟 总被引:4,自引:0,他引:4
采用热力学耦合有限元方法研究了淬硬钢精车过程中切屑形成规律。运用H13 淬硬模具钢流动应力模型进行数值模拟,考查了H13淬硬模具钢精车过程中工艺参数对工件性能和刀具的影响。结果表明:切削速度愈高,进给量愈小,刀具刀尖半径愈大,则工件加工层上的静水拉应力愈小,表面质量愈好; 淬硬钢精车时径向力起主要作用,大于切削力;切削速度愈大,切削力和径向力则愈小,愈有助于改善工件加工层上的表面质量;切削速度、进给量和刀具刀尖圆角半径愈大,工件和刀具温度愈高,愈易导致刀具前刀面扩散磨损和刀具后刀面磨损。研究结论有助于优化H13淬硬模具钢精车过程中工艺参数选择和改进刀具镶片设计。 相似文献
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Xiangyu WANG Chuanzhen HUANG Bin ZOU Guoliang LIU Hongtao ZHU Jun WANG 《Frontiers of Mechanical Engineering》2018,13(2):243-250
The Inconel 718 alloy is widely used in the aerospace and power industries. The machining-induced surface integrity and fatigue life of this material are important factors for consideration due to high reliability and safety requirements. In this work, the milling of Inconel 718 was conducted at different cutting speeds and feed rates. Surface integrity and fatigue life were measured directly. The effects of cutting speed and feed rate on surface integrity and their further influences on fatigue life were analyzed. Within the chosen parameter range, the cutting speed barely affected the surface roughness, whereas the feed rate increased the surface roughness through the ideal residual height. The surface hardness increased as the cutting speed and feed rate increased. Tensile residual stress was observed on the machined surface, which showed improvement with the increasing feed rate. The cutting speed was not an influencing factor on fatigue life, but the feed rate affected fatigue life through the surface roughness. The high surface roughness resulting from the high feed rate could result in a high stress concentration factor and lead to a low fatigue life. 相似文献
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The residual stress distribution in the surface region of workpieces of a bearing bronze that is machined under unlubricated, orthogonal conditions is determined using a deflection etching technique. The residual stress at the surface is low (compressive) and increases with an increase in depth beneath the machined surface to a maximum (tensile) then decreases continuously with a further increase in depth eventually becoming vanishingly small. The peak residual stress and depth of the stressed region increase with an increase in cutting speed, an increase in feed rate and an increase in tool rake angle but are independent of tool wear land length. The results of the investigation are interpreted qualitatively in terms of the type of chip produced and the variation of the thickness of the deformed surface region with cutting conditions. 相似文献
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Results of X-ray residual stress measurements on Inconel 718 turbine shaft samples are here proposed. The paper presents part of the EU STREP project VERDI activity, where the aim was to supply those who numerically simulate machining process with an experimental database of proved reliability. Measurements were planned on a set of samples machined with different levels of cutting speed and feed rate. Due attention was given to the assessment of the uncertainty of experimental results. A database of surface residual stress values and depth profiles is presented with the estimated uncertainty both on stress and depth values. The stress proved to be always tensile at the surface and compressive below the surface. Higher cutting speed and feed rates produce higher surface tensile stresses but the trends are different for the two measurement directions. 相似文献
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切削温度与刀具磨损、工件加工表面完整性及加工精度密切相关,其变化规律反映出高速切削过程本质的重要方面。本文应用数值模拟,对高速切削加工过程中切屑、工件和刀具三方面的温度随切削速度、进给量、切削深度的动态变化进行了研究,探讨了其变化规律,其结论有助于优化高速切削工艺及建立高速切削数据库。 相似文献
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《Measurement》2016
Residual stresses are usually imposed on a machined component due to thermal and mechanical loading. Tensile residual stresses are detrimental as it could shorten the fatigue life of the component; meanwhile, compressive residual stresses are beneficial as it could prolong the fatigue life. Thermal and mechanical loading significantly affect the behavior of residual stress. Therefore, this research focused on the effects of lubricant and milling mode during end milling of S50C medium carbon steel. Numerical factors, namely, spindle speed, feed rate and depth of cut and categorical factors, namely, lubrication and milling mode is optimized using D-optimal experimentation. Mathematical model is developed for the prediction of residual stress, cutting force and surface roughness based on response surface methodology (RSM). Results show that minimum residual stress and cutting force can be achieved during up milling, by adopting the MQL-SiO2 nanolubrication system. Meanwhile, during down milling minimum residual stress and cutting force can be achieved with flood cutting. Moreover, minimum surface roughness can be attained during flood cutting in both up and down milling. The response surface plots indicate that the effect of spindle speed and feed rate is less significant at low depth of cut but this effect significantly increases the residual stress, cutting force and surface roughness as the depth of cut increases. 相似文献
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Farshid Jafarian Hossein Amirabadi Mehdi Fattahi 《The International Journal of Advanced Manufacturing Technology》2014,71(5-8):817-827
In machining of hard materials, surface integrity is one of the major customer requirements which comprise the study of the changes induced to the workpiece. Surface roughness and residual stress are often considered as the most significant indications of surface integrity. Inducing tensile residual stress during the machining processes is a critical problem which should be avoided or minimized to obtain better service quality and component life. This problem becomes more evident in the presence of rough machined surface because fatigue life of manufactured components might be decreased significantly. Inconel 718 superalloy is one of the hard materials used extensively in the aerospace industries. It is prone to tensile residual stress in machined surface. Thus, controlling and optimizing residual stress and surface roughness in machining of Inconel 718 are so needed. Intelligent techniques based on the predictive and optimization models can be used efficiently for this purpose. In this study, the optimal machining parameters including cutting speed, depth of cut, and feed rate were accessed by intelligent systems to evaluate the state of residual stress and surface roughness in finish turning of Inconel 718. The results of experiments and analyses indicated that implemented techniques in this work provided a robust framework for improving surface integrity in machining of Inconel 718 alloy. It was shown that cutting speed has more effect on surface integrity than other investigated parameters. Also, depth of cut and feed rate were found in the moderate range to obtain satisfactory state of tensile residual stress and surface roughness. 相似文献
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预应力切削镍基高温合金的试验研究 总被引:5,自引:0,他引:5
针对镍基高温合金在切削后加工表面分布严重的残余拉应力等问题,提出采用预应力切削方法,以实现在加工过程中主动控制加工表面残余应力分布状态;通过研制轴类零件的车床专用预拉伸装置,在0 MPa、150 MPa和300 MPa三种预应力条件下对高温合金轴件进行预拉伸处理;通过硬质合金刀具预应力切削镍基高温合金的对比试验,对三种预应力条件下的切削力、切屑形态以及表面完整性包括已加工表面残余应力、加工表面粗糙度、表面形貌和显微硬度等指标进行对比。结果表明:在一定范围内,采用预应力切削方法可省去加工后续的残余应力调整工序,并能在加工表面获得合适的残余压应力;残余压应力的值可通过调整施加的预应力大小来进行主动控制;与普通切削相比,预应力切削可得到均匀的锯齿形切屑,切削力没有显著增加;预应力切削可获得良好的表面完整性,且不会引来额外的加工硬化。 相似文献