四爪翼轴的自由锻造工艺

四爪翼轴是我所开发研制的新型食品机械设备上的重要承力零件,见图所示,也是典型的叉形、枝芽类零件。这类零件的毛坯生产一般采用乙炔焰切割厚板或压力加工方法。 1.工艺方法选择 用乙炔焰或其它高能束流切割厚板得到四爪翼轴机加工毛坯件,经铣削成形,具有加工方法简单、毛坯生产率高等优点,但会割断基体材料的纤维流线,降低强度而影响使用性能,还因需要留有较大的机械加工余量,造成材料浪费。用模锻、自由锻造等压力加工方法生产毛坯是较好的工艺选择,特别是用锻模模锻成形,成材率高、锻件质量好,适宜于批量生产;但此法至少需要预锻、终锻和切边三套锻模,一次性投资较大。故在实际应用时,应认真分析。而自由锻更为实用。     

用等温模锻方法制造盘形刀具毛坯的特点

<正> 薄盘形刀具毛坯的结构特点是直径与厚度的比例悬殊大(D/H=6～50)。采用一般的锻造和热模锻方法可制出D/H 之比不大于6、4的盘形铣刀毛坯,这是由于高速钢塑性较低,变形抗力大以及有氧化和脱炭等趋势所致。从高速钢钢板冷冲下的坯料来制造锯片铣刀毛坯时,金属的利用率低,留下的废料多,而由热轧棒料用自由锻造方法制造盘形模数铣刀毛坯,因其下一序的机加工留量大(一边为.5～2毫米)以及出现裂纹废品等原因,造成金属大量损耗,甚至于有烧损、氧化皮和脱炭层等损耗。此外,自由锻造后必须在专用炉内进行较长时间的退火,退火炉的电能消耗量较大,所占的生产面积也很大。     

长尾锥齿轮坯温挤成形

长尾锥齿轮(图1)的毛坯一直是采用热模锻成形,但由于高温氧化、加工精度低、加工余量大等原因,造成材料利用率只有28～ 34％,材料费为齿坯价格的69～72％,机加工时和刀具消耗也相应增大。针对该类齿轮材料为18Cr2Ni4WA钢和尾长、心空等特征,经多种方案对比,可以选用温挤成形新工艺。     

节能节材是锻造企业系统持续发展的推动力

正企业在节能节材的工作方针指导思想是以工艺开发为龙头,统筹规划,开源节流。我单位主要生产各类重型载重汽车零件模锻毛坯,其中大型锻件有125M N热模锻压力机和16吨模锻电液锤生产线生产的重型汽车发动机曲轴和前轴模锻毛坯。企业在节能节材的工作方针指导思想是以工艺开发为龙头,统筹规划,开源节流。1.统筹规划企业在新项目建设伊始就将节能节材思想贯穿于规划设计建设全过程,从车间厂房风水电气各专业设备到工艺设备选型及工     

大规格螺母的热模锻成形

在标准紧固件的生产中,M24mm以下规格的螺母一般在冷镦机上成形。M24mm以上规格的螺母通常在热镦机上或摩擦压力机上成形。M30mm以上规格的螺母大多数企业在通用摩擦压力机上热模锻成形,普遍采用的工艺方法是先将一段毛坯圆料经一次“压成球状”工艺后,再二次模锻成螺母     

LT拖拉机半轴

河南省中原轴件厂是专业化生产轴类零件的大型国有企业,现有职工1700人,工程技术人员256人。下设花键轴、齿轮轴、汽车半轴、热处理、热模锻、锻造等八个分厂。年产花键轴200万件,汽车半轴51万件,齿轮轴50万件,锻造毛坯8000吨,年综合产量2.6万吨。零部件产品为一汽、二汽、北京切诺基、一拖、大柴等国家大型企业配套。     

用曲柄热模锻压机床生产管线法兰件

在现代锻造生产中,为成批制造环形锻件,其中包括法兰锻件,一般采用3种可保证大致相同和足够高水平锻件质量的热变形方法:热模锻、辗扩、带预辗扩环形毛坯的热模锻。 热模锻法兰锻件一般用4道工序实现:镦粗、最终成形、冲孔和切边。这时锻件的尺寸和形状可达到所需精     

液态模锻黄铜保持架毛坯

轴承行业黄铜保持架毛坯的生产工艺一贯采用离心铸造技术 ,毛坯加工余量大 ,材料利用率低 ,铸件不可回收损失大。为了减少毛坯重量 ,提高材料利用率 ,我们经过长期的研究和实践 ,实现了利用液态模锻技术生产黄铜保持架毛坯。液态模锻的模具图见图 1。保持架毛坯形状见图 2。使用设备为 2 0 0ｔ压力机。　　液态模锻保持架毛坯的精度高 ,加工留量少 ,1-模座 ;2 -卸料板 ;3 -顶料杆 ;4-型腔 ;5 -毛坯 ;6-上压头图 1图 2同时将保持架的兜孔压制成形 ,从而减轻了毛坯的重量。实践证明 ,液态模锻工艺比离心铸造工艺的效益显著。其对比见表 1。从…     

平面圆盘法兰批量制作的一种新方法

平面圆盘法兰批量制作,按工序可以分成两阶段:制作圆盘毛坯和将圆盘毛坯精加工成标准的成品.批量制作圆盘毛坯有几种不同的方式,一种是直接用热轧厚板进行等离子切割或激光切割,一种是利用模锻的方式,现推荐介绍一种新的制作方法:将热轧扁材经卷绕机卷成螺旋卷筒状,锯切分开、粗矫正、焊接、打磨、精矫正;再经双头机床、多轴钻床加工至标准的法兰成品;此种方式加工法兰的特点是设备成本低,材料利用率高、生产批量大、适用性强、生产效率高.     

多向弯曲类锻件组合锻造方法的探讨

多向弯曲类锻件外形复杂,多向弯曲,截面差与落差大,如果用传统的锤上模锻生产,其锻件精度较差,能耗大。本文提出“辊锻-摩擦压力机模锻”的组合工艺锻造方案,介绍有关辊锻毛坯,弯曲毛坯,弯曲回弹,弯曲工序的合理安排等工艺设计要点及模具的合理结构与设计,特别是锁扣结构的运用。本工艺方案有操作简单,劳动强度低,生产过程稳定可靠、效率高的特点。     

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.     

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。     

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....     

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.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.