薄壁钛合金材料零件旋压的热处理工艺

钛合金密度小,比强度高,比模量高,结构性能优异,然而钛合金材料价格昂贵。掏空钛合金棒料制成薄壁壳体类零件,不仅材料利用率低,加工周期长,而且刀具磨损快,加工成本居高不下。旋压成形技术能很好地解决薄壁钛合金材料加工成本高、效率低等问题,但钛合金材料在常温下塑性差,变形抗力大,不易旋压成形。本文针对此难题,提出了钛合金材料旋压过程的热加工方法,得出了钛合金材料旋压成形的热处理参数。     

钛合金薄壁零件加工工艺技术研究

结合钛合金零件的加工特点,对钛合金薄壁零件进行深入分析,通过切削刀具材料、刃磨角度、切削要素、加工流程、浇注方式和夹紧力的制定等参数选择,解决钛合金薄壁零件精度高、难加工和易变形的切削难题。提高零件加工质量,从而达到保证零件尺寸精度及形位公差的目的。     

大长径比薄壁零件旋压工艺研究

大长径比薄壁零件越来越多地应用于军工行业,人们对此类零件的质量要求也越来越高,此类零件采用传统加工方法易产生弯曲、变形、壁厚不均匀等问题,旋压加工成形的显著优点是能够提高形状复杂零部件及高难度易变形材料的加工质量。通过对战斗部中心管这类大长径比薄壁零件采用旋压加工的实例分析,在研究了传统加工方法的基础上,提出了正旋工艺成形的工艺方案,同时,对旋压加工中的难点采取一系列工艺措施,有效解决了大长径比薄壁零件的加工难题。通过在军工产品实际生产中进行推广应用发现,该类零件采用旋压加工后可有效解决车削加工出现的问题,产品质量稳定、可靠,生产效率及产品合格率得到了提高,为该类型零件加工提供了可借鉴的经验。     

切削参数对弯曲薄壁件变形规律的有限元仿真

钛合金薄壁件在切削加工时易产生弹性变形,降低薄壁件的加工质量。针对钛合金弯曲薄壁零件加工易变形的问题,建立了薄壁零件的有限元模型,研究了刀具在加工零件时不同位置和不同切削参数下对薄壁零件铣削变形的影响,确定了零件的最大变形点,并运用多指标正交试验确立了最优的刀具切削参数。     

钛合金支架零件工艺解决方案

正钛合金材料由于强度好,重量轻的特点,广泛应用于航空、航天和兵器行业,但是钛合金导热系数低、塑性低、弹性模量低和弹性变形大等特点,造成切削性能差,加工变形不易消除,高精度的零件关键尺寸不易保证。本文通过分析钛合金薄壁支架零件的加工,成功解决变形问题来探讨钛合金的特点。1.钛合金支架加工工艺分析(1)用附图所示零件展开工艺分析。     

钛合金精密零件镗铣加工工艺

对钛合金精密零件加工工艺技术的研究,通过选用适合加工钛合金材料的刀具、切削要素,提高钛合金精密零件加工质量,通过制定合理的热处理参数及工艺流程消除零件加工应力,稳定零件加工尺寸,选用合适的定位方式消除零件的加工过定位,保证零件加工尺寸精度,试验表明此工艺加工方法可消除零件加工变形,稳定加工尺寸,使钛合金精密零件合格率达到95%以上,从而达到保证零件尺寸精度的技术要求。     

某框间尾梁上壁加工技术

针对如何控制钛合金薄壁超塑成形件变形及提高零件表面粗糙度的问题,开展了工艺方法的研究,有效解决了超塑成形零件刚性差、变形量大、表面粗糙度低、尺寸难测量等一系列难题,填补数控加工薄壁超塑成形零件技术的空白。     

钛合金薄壁高筒零件的切削加工工艺

针对TA1钛合金薄壁高筒零件加工后易产生变形超差,生产效率较低的问题,研究TA1钛合金材料的物理性能、力学性能,分析工艺难点,设计合理的加工工艺路线和切削参数,进而提出钛合金薄壁高筒零件切削加工工艺。采用所提出的切削加工工艺,可以有效控制钛合金薄壁高筒零件的加工变形,提高加工效率。     

钛合金薄壁锥形滤网的数控加工

通过分析钛合金薄壁锥形滤网的加工难点,针对加工过程出现的网格形位偏移、网格破裂、厚度不均和厚度超差等缺陷,制定了该零件的数控加工工艺。采用提高零件自身结构刚度、装夹刚度以及销孔周向准确定位的优化措施,有效解决了因加工震颤而导致网格形状位置偏移和破网的问题,保证了薄壁滤网壁厚尺寸精度。优化后的加工工艺是保证钛合金薄壁锥形滤网加工质量的关键,可为类似钛合金薄壁零件的加工提供参考。     

数控机床薄壁零件的加工研究

随着薄壁零件在各领域应用的越来越广泛,其加工过程中易变形、加工难度大等问题逐渐暴露出来,本文从薄壁零件的特点出发,对薄壁零件在数控加工中的切削力、装夹等影响因素进行了分析,并提出了相应的应对措施,希望能够有效解决薄壁零件加工精度差和尺寸不稳定等难题,为薄壁零件的加工提供借鉴。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.