共查询到20条相似文献,搜索用时 211 毫秒
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对超硬高速钢中铝高速钢与普通高速钢的红硬性进行了对比试验,对三种材料的丝锥进行了切削试验研究。结果表明:铝高速钢、钴高速钢丝锥的使用寿命比普通高速钢有较大的提高;对普通高速钢成品丝锥进行深冷处理同样能提高其使用寿命。 相似文献
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硬质合金丝锥由于其比高速钢丝锥高得多的耐磨性而得到越来越广泛的应用,大量用于铸铁、铝合金、硬青铜、耐热合金、淬火钢及硬塑料、玻璃钢等零件上螺纹孔的加工。由于其丝锥刃部是硬度很高的硬质合金材料,加工此类丝锥时难度较大,用普通高速钢丝锥的工艺方法已无法满足要求,必须采用特殊的加工手段才能完成,因此丝锥制造难度大、成本高。不仅如此, 相似文献
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高速钢丝锥刃口电解强化技术 总被引:9,自引:0,他引:9
研究一种刀具刃口的电解强化方法,以期提高刀具寿命和切削稳定性.设计刀具刃口电解强化装置和工艺流程.以高速钢丝锥为实例,确定刀具刃口电解强化的电解液配方,选择阴极材料等工艺参数,研究刃口强化量与极间距离、电流密度、抛光持续时间和极间电压之间的关系.用优化工艺参数电解强化处理丝锥,刃口整齐,丝锥各刀齿刃口强化量均匀,符合刃口强化的几何形状,刃口强化后丝锥前刀面表面粗糙度降低.利用以上研究结果,进行切削40Cr、ZG230~450和1Cr18Ni9Ti的切削试验,加工400r和ZG230~450丝锥寿命提高2倍左右,加工不锈钢丝锥寿命影响不明显.研究表明,采用电解强化方法处理高速钢丝锥可以提高其使用寿命,效果与被加工材料和刃口强化量有关. 相似文献
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<正> 美国VNE公司开发了一种用于小螺孔加工的窄小刀片(Mini Thread刀片),该刀片带有双棱车螺纹刃,可车削螺纹的最小孔径为7.3~8.0mm,但要根据加工的螺纹形状而定。该刀片安装在刀杆上,有4种有效长度,最长为43mm。刀片可加工螺距为0.5~2.0mm的所有通用螺纹的全轮廓或部分轮廓。两个切削刃位于刀片的相对面上,当用一个切削刃进行切削时,另一个切削刃可得到很好的保护。这种窄小刀片可采用PVD涂层的高速钢或硬质合金制成,加工出的螺纹质量比攻丝效果好。对于象不锈钢之类的材料,用丝锥加工螺纹常会发生折断现象,如 相似文献
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Influence of geometric and cutting parameters of cemented carbide cutting tool on reliability of cutting tool has become more and more mature, yet influence of its physical and material parameters on reliability is still blank. In view of this, cutting test and fatigue crack growth test of YT05 cemented carbide cutting tool are conducted to measure such data as the original crack size, growth size, times of impact loading, number and time of cutting tool in failure, and stress distribution of cutting tool is also obtained by simulating cutting process of tools. Mathematical models on dynamic reliability and dynamic reliability sensitivity of cutting tool are derived respectively by taking machining time and times of impact loading into account, thus change rules of dynamic reliability sensitivity to physical and material parameters can be obtained. Theoretical and experimental results show that sensitive degree on each parameter of tools increases gradually with the increase of machining time and times of impact loading, especially for parameters such as fracture toughness, shape parameter, and cutting stress. This proposed model solves such problems as how to determine the most sensitive parameter and influence degree of physical parameters and material parameters to reliability, which is sensitivity, and can provide theoretical foundation for improving reliability of cutting tool system. 相似文献
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复杂载荷作用下压气机叶片疲劳寿命数值分析 总被引:1,自引:0,他引:1
为提高叶片服役寿命,在计算叶片应力分布并预测其在复杂载荷作用下的疲劳寿命后,基于逆向工程建立了三种不同精度的叶片模型;考虑离心和气动载荷作用,求解压气机叶片复合载荷作用下的应力分布规律;通过叶片模拟件疲劳试验,确定TC4钛合金疲劳极限,拟合寿命模型参数;利用非线性连续损伤力学模型预测叶片在典型工况下的疲劳寿命。结果表明:不同模型的应力及寿命计算值存在一定差异,开展叶片数值分析时,需考虑计算模型还原叶片几何特征的精度对计算结果的影响。 相似文献
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基于唯象的剩余强度衰减模型与蔡-希尔静强度判据,建立单向层合板在任意复杂面内应力作用下的疲劳失效准则。利用蒙特卡洛模拟方法计算层合板的疲劳寿命,并对其进行可靠性评估。根据T300/QY8911的三种典型层合板[0]16、[90]24和[±45]3S的拉—拉疲劳试验结果,利用蒙特卡洛模拟方法计算层合板的疲劳寿命,结果表明寿命服从Weibul分布。 相似文献
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随机恒幅循环载荷疲劳可靠度异量纲干涉模型 总被引:3,自引:0,他引:3
用于与时间无关的失效模式(例如静强度失效)的失效概率或可靠度计算的"应力-强度干涉模型"已很成熟,但要将干涉分析的概念与方法应用于与时间相关的失效模式(例如疲劳、磨损和腐蚀等)还存在许多困难,即使对于存在不确定性的恒幅循环载荷下的疲劳可靠性问题,目前也还没有像静强度应力-强度干涉模型那样简单、直接、有效的方法及数学模型.在概率统计平均的意义上重新解释传统的两个随机变量干涉分析的基本概念及模型,将干涉模型解释为载荷加权平均模型.具体地讲,就是将应力-强度干涉模型解释、拓展为强度超越(载荷)概率的(载荷)统计加权平均模型,或给定应力下的条件失效概率的随机载荷加权平均模型.这样,传统上只能应用于相同量纲随机变量(例如应力与强度)的干涉模型就可以拓展应用于具有不同量纲随机变量(例如应力与寿命)的情形,例如随机载荷下的疲劳失效概率(寿命小于指定值的概率)或可靠度(寿命大于指定值的概率)计算.应用这样的模型,可以很方便地根据几个确定性恒幅循环载荷下的疲劳寿命分布,预测随机恒幅循环载荷作用下的疲劳失效概率或可靠度. 相似文献
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Zhaoliang Jiang Yumei Liu Lin Li Weixian Shao 《The International Journal of Advanced Manufacturing Technology》2014,74(1-4):37-45
Residual stresses induced by machining coupled with the initial stresses can significantly impact mechanical properties of workpieces such as distortion, corrosion resistance, and dimensional stability. The redistribution pattern of residual stresses is extremely complex. The stress relieving can seriously deform the workpieces and reduce the fatigue life. Therefore, deflection prediction is critical for design, control, analysis, and management of machining. In this paper, an integrated modeling method is introduced to predict the deflection caused by milling residual stresses, to be more exact, to map the relationship between the deflections and the cutting parameters. Response surface design (RSD) is utilized to develop a new mathematical model which can predict the residual stress profiles of the workpieces along the cutting direction based on different cutting parameters. Then, the deflections are derived based on the estimated stress profiles and mechanics of materials theory. A finite element analysis model (FEM)-based simulation experiment using aluminum alloy 6061 as a case study has been implemented. The results from experiments indicate that the proposed approach could precisely estimate the residual stress profiles for given cutting parameters and effectively predict the deflections of the workpieces caused by residual stress. 相似文献
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在刀具寿命分布参数神经网络预报技术的基础上,建立基于刀具可靠性的最大生产率优化模型,提出实用的优化方法,根据新的优化模型,以最大生产率为目标函数可以对不同换刀方式下切削用量和换刀间隔进行宽范围优化。对自动化切削加工实例的优化结果表明,新的优化模型适合于自动化切削加工过程的优化。 相似文献
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Planetary gear systems have been widely used in transportation, construction, metallurgy, petroleum, aviation and other industrial fields. Under the same condition of power transmission, they have a more compact structure than ordinary gear train. However, some critical parts, such as sun gear, planet gear and ring gear often suffer from fatigue and wear under the conditions of high speed and heavy load. For reliability research, in order to predict the fatigue probability life of planetary gear system, detailed kinematic and mechanical analysis for a planetary gear system is firstly completed. Meanwhile, a gear bending fatigue test is carried out at a stress level to obtain the strength information of specific gears. Then, a life distribution transformation model is established according to the order statistics theory. Transformation process is that, the life distribution of test gear is transformed to that of single tooth, and then the life distribution of single tooth can be effectively transformed to that of the planetary gear system. In addition, the effectiveness of the transformation model is finally verified by a processing method with random censoring data. 相似文献
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随机载荷下疲劳寿命的估算 总被引:3,自引:1,他引:3
复杂随机载荷下疲劳寿命的评估,一直是工程上所关心的问题之一。在设计阶段,通常难以确定详细的应力历程,因而也无从进行循环计数和累计损伤。本文基于传统的疲劳设计思想和概率分析方法,综合考虑平均应力的影响和疲劳寿命固有的分散性,研究了宽带随机载荷作用下疲劳寿命的估算问题 相似文献