共查询到19条相似文献,搜索用时 171 毫秒
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对应用谐波振动消除机床床身铸造残余应力的方法进行了实验研究。实验结果的对比表明,该方法能够显著地降低铸件生产中残余应力对铸件精度的影响,是一种可显著缩短机床生产周期的新型工艺方法。 相似文献
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采用无损X射线衍射技术,利用X-350A型X射线应力测定仪的侧倾固定ψ法测量铸造支座的残余应力,得到铸造支座底部和铸造支座圆柱部位的残余应力值以及一般分布规律。采用标准偏差计算方法得出铸造支座底部和圆柱部位残余应力的取值区间,为今后支座铸造工艺设计、制造、支座结构设计等提供指导,改善热处理工艺。 相似文献
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以某公司生产的大型机床床身铸件为研究对象,研究通过在床身铸件铸造过程中,应用高频振动工艺控制铸件的凝固过程,改善铸件的金相组织和相组成均一性,进而改善床身铸件的尺寸精度。通过高频振动对大型床身铸件进行凝固晶粒细化消除内应力根源,同时应用热处理时效进一步进行应力消除,再利用盲孔法检测铸件的残余应力。利用扫描电镜(SEM)观察材料的显微结构,并进行相应的相结构和成分分析。结果显示,床身铸件应用振动凝固工艺,有效地消除工件内部的残余应力,经振动凝固可有避免凝固过程中的残余应力28.72%。床身铸件经热时效处理后,应力消除92.64%。综合应用振动凝固工艺及热处理时效之后,其II类残余应力有效消除≥95%。它为生产该类型产品提供技术参考和指导。 相似文献
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振动时效工艺主要是通过让工件产生变形振动,达到消除、减小和均化各种铸件、焊接件、锻件、机加工件的铸造热应力、焊接残余应力、热锻表面应力、切削应力、冲压应力的目的。 相似文献
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本文用X射线应力仪研究了低应力高强度灰铸铁从表面开始沿怪深分布的残余应力测试方法,通过对机床床身铸造应力的实测,结合应力场的数值分析结果,提出了灰铸铁件在应用取消人工时效工序的同时控制热应力符合质量指标的监测技术。 相似文献
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二重集团公司整体铸造的GS-20Mn5V大型轧机机架,重约400 t.铸件清理时发现裂纹,必须进行焊补和焊后整体消应.为确定焊补工艺和了解机架消应前后残余应力的实际分布状态,找出高应力区的位置,对工艺评定试板和机架在消应前后的残余应力进行了测定,解决了大型铸造轧机机架残余应力测定的难题. 相似文献
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18CrNiMo7-6渗碳淬火齿轮钢具有较高的强度和优良的机械性能,在风电减速器齿轮和高速机车齿轮等领域应用广泛。磨削是用于实现零部件的最终表面质量的一种重要的机械加工方式,其中表面残余应力在零部件的疲劳寿命中起重要作用。为了研究高速磨削表面的残余应力分布状态,设计了磨削过程中磨削温度和磨削力的测量方案,以单因素试验分析方法为主。以高速精密磨削不同的工艺参数产生的磨削力和磨削热为对象以分析表面残余应力,得出以下结论:较小磨削深度的情况下,高速磨削过程中磨削温度存在萨洛蒙曲线,对磨削表面残余应力的产生有较大影响主要为磨削热,磨削力影响不明显;沿磨削的不同方向的残余应力的绝对值有差别,垂直于磨削方向的绝对值较大。 相似文献
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Zheng Zhang Liang Li Yinfei Yang Ning He Wei Zhao 《The International Journal of Advanced Manufacturing Technology》2014,73(9-12):1765-1773
The distortion of machined parts is a major concern in the manufacture of aeronautical monolithic structures. We investigated the influence of material removal partition on residual stress in high-strength aluminum alloy parts to minimize machining distortion. In the present study, a methodology of minimizing machining distortion based on an accurate cross-sectional residual stress determination is presented, which can be applied to avoid or minimize part distortions in advance by adapting machining strategies or process conditions. A powerful contour method was used first to measure bulk residual stress within the blank. Next, a finite element model was applied to predict machining distortion based on measured residual stress for analyzing part distortion. Finally, experimental verification was provided by comparing measured distortion and predicted distortion by the finite element analysis. This simulation showed that part distortion is mainly affected by the partition of material removal in T-shaped components. Our results also indicate that distortion can be minimized by optimizing the partition of material removal to ensure a symmetrical distribution of residual stress in the part so that the residual stress-induced bending moment could reach self equilibrium. 相似文献
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Xiaohui Jiang Beizhi Li Jianguo Yang Xiao Yan Zuo 《The International Journal of Advanced Manufacturing Technology》2013,68(1-4):175-186
Residual stress has a sustained impact on the deformation of thin-walled parts after processing, raising the strict restrictions required in their using procedure. In general, with regard to thin-walled parts, different processing parameters will affect the distortion and residual stress generation of the workpiece, which play the key role in the machining. However, controlling the material removal rate is also quite critical to machining of thin-walled parts. In order to reach these goals, based on the relation between residual stress and uncut chip thickness (UCT), a method is proposed by optimizing the milling tool diameters. The research finding reveals that, by improving the tool diameter, at the same circular position, smaller UCT can be achieved. In addition, take 6 and 12 mm tool diameter as analysis cases; larger tool diameter can reduce the residual tensile stress distribution significantly (the ratio ranges from 13.9 to 34.7 %) and improve the material removal rate. Moreover, a typical thin-walled part is evaluated using different tool diameters (6 and 12 mm) by experiments, as the final distortion can be decreased by 60 % with 12-mm tool diameter. The distribution of machined surface and subsurface residual stress is turning to be more uniform. Hence, it proves that, under the goals of maintaining machining accuracy and material removal rate, also improving the distribution of residual stress, it is possible to achieve by controlling the UCT (tool diameters) in the processing of thin-walled. All these findings can help to enhance the milling precision of thin-walled parts, as well as control and optimize the residual stress distribution. 相似文献
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在ABAQUS软件中模拟了2A12铝合金的淬火过程,进行了实际板材淬火和钻孔法应力测量试验,仿真所得板材表面应力值与实际测量结果误差约为10.1%~16.5%,且都具有对称分布的特点,说明通过淬火仿真获得的板材内应力分布与实际淬火相吻合.基于仿真的应力分布进行加工仿真,研究了单框零件相对板厚位置对加工变形的影响,提出了由板材加工框形零件的加工变形控制策略. 相似文献
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Yu Wei X. W. Wang 《The International Journal of Advanced Manufacturing Technology》2007,33(3-4):260-265
Aerospace thin-walled parts have a complex structure and high accuracy. Factors such as original residual stress, fixing,
and machining may make low-rigidity parts deform easily, which is difficult for traditional craftwork to forecast and control.
Especially in machining big aerospace parts, original residual stress has a great effect on machining deflection. In this
paper finite element model of original residual stress is established to analyze the corresponding deflection by machining
aerospace thin-walled parts. Simulation results are validated consistent with experimental results approximately. At last
the paper puts forward the corresponding mend methods to control the deflection caused by original residual stress during
the actual machining process. 相似文献
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介绍了一种气缸盖多轴点位加工的参数变量编程技术。基于WRD130Q落地镗铣加工中心的多轴加工应用技术,根据大功率船用低速柴油机零件气缸盖的孔系分布特性,对气缸盖零件的多轴数控加工编程应用进行了较深入的理论与实践的研究;并利用西门子SINUMERRIK 840D数控系统的参数变量编程格式,设计编制了一套多轴点位加工的程序模板,为大功率船用低速柴油机零件的多轴加工应用提供了一套有效的数控加工编程方案。 相似文献
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钛合金铣削加工表面残余应力研究 总被引:3,自引:0,他引:3
金属切削加工引起的残余应力对零部件变形、疲劳性能有重要影响,通过选择合适的加工参数对其进行控制是可能的。目的在于研究钛合金铣削加工中铣削参数对已加工表面残余应力的影响,利用X射线衍射技术测量进给方向和铣削方向的残余应力。为保证X射线应力测量精度,采用摇摆法和峰拟合定峰方法。试验结果表明,钛合金顺铣加工表面残余应力表现为压应力,主要是由于刀具后刀面与已加工表面的挤光效应起主导作用所致。沿铣削方向和进给方向,切削参数对工件表面残余应力影响具有差异性。通过控制切削参数有可能生成定制化的应力。 相似文献
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毛坯残余应力对薄壁件整体加工变形有重要影响。利用大型通用有限元软件ANSYS10.0对钛合金TC4进行退火过程数值模拟研究,通过数值模拟获得了退火过程中温度的变化、残余应力的分布及最终冷却后的残余应力状态。为研究TC4的加工变形规律,提供了具有初始残余应力场的数字化毛坯。 相似文献