低温用3.5Ni钢管的焊接性试验研究

在工期紧张无法进行焊后热处理的情况下,通过焊接试验,制定合适的焊接工艺,将3.5Ni低温钢管焊接线能量控制在18kJ/cm以内,并采用焊后氩弧重熔工艺,控制焊缝粗晶组织的出现,从而保证接头的低温冲击韧性。     

浅析氩电联焊工艺在压力管道焊接施工中的缺陷控制

在使用氩电联焊工艺对压力管道进行焊接时,应该科学地应用电焊机,从而实现打底和填充工作,从而把各种缺陷控制在合理的范围内。这项工艺的适用范围较广,并且施工效率较高。本文对氩电联焊工艺的原理和实施流程进行简单介绍,探究功能工艺的应用价值,总结在压力管道焊接施工中氩电联焊工艺控制缺陷的模式。     

特大型圆锥滚子轴承支柱保持架氩弧焊接技术

分析特大型圆锥滚子轴承支柱焊接保持架目前普通电弧焊接存在的问题,改进采用氩弧焊接方法,并对保持架倒角进行改进。通过工艺对比验证了支柱氩弧焊接的优越性,支柱氩弧焊接无焊渣飞溅,焊帽质量更好,满足了强度要求,并对焊接的检测进行了说明。     

35CrMo法兰与Q345管材的焊接工艺

采用氩电联焊的方法焊接35CrNo和Q345（16Mn）钢。此类异种钢的焊接要注意焊前预热和焊后热处理。按正确的工艺焊接，焊后检验合格。     

20钢含硫天然气管线焊接工艺应用研究

本文从降低成本、缩短进料周期等角度出发,根据前线施工单位具体情况,灵活应用,提出以国产J427焊条替代进口焊条,采用氩电联焊方法进行了20钢含硫管线的焊接。焊接接头经应力腐蚀试验等检测后完全满足标准要求,其工艺已应用于现场施工,大大降低了生产成本,取得了令人满意的效果。     

中小径薄壁管氩弧自动焊设备研究与应用

对氩弧自动焊设备及中小径薄壁管氩弧自动焊工艺进行了研究,通过焊接试验表明,氩弧自动焊设备操作简单,焊接过程稳定,可以提高产品质量和生产效率,降低焊工劳动强度及制造成本,可在中小径薄壁管焊接生产中广泛应用。     

LD10CS、LF6y_2铝合金的熔化极脉冲弧焊接

本文介绍应用熔极脉冲弧焊接(M1G-PAW)方法焊接LD10 CS、LF6Y_2铝合金的工艺。文中从焊接热输入、焊接变形、接头的机械性能和金相组织等方面对T1G与M1G作了比较。采用M1GPAW时,对不同厚度的材料采用氦-氩和纯氩等不同保护气体,并采用不同的熔滴过渡方式(分别采用射流、介射流、半短路三种过渡方式)通过工艺试验制订出一系列工艺参数。将五十年代陈旧的埋弧焊设备改装为简易的脉冲焊机是挖潜、革新和改造的具体措施。     

LD10CS、LF6y_2铝合金的熔化极脉冲弧焊接

本文介绍应用熔极脉冲弧焊接(M1GPAW)方法焊接LD10 CS、LF6Y_2铝合金的工艺。文中从焊接热输入、焊接变形、接头的机械性能和金相组织等方面对T1G与M1G作了比较。采用M1GPAW时,对不同厚度的材料采用氦-氩和纯氩等不同保护气体,并采用不同的熔滴过渡方式(分别采用射流、介射流、半短路三种过渡方式)通过工艺试验制订出一系列工艺参数。将五十年代陈旧的埋弧焊设备改装为简易的脉冲焊机是挖潜、革新和改造的具体措施。     

大型轴流压缩机机壳焊接工艺及变形控制

分析了大型轴流压缩机焊接机壳的结构特点,选择(Ar)80%+(CO2)20%富氩混合气体保护焊的焊接工艺方法,并按标准进行了相关工艺试验,通过合理的拼装顺序有效控制了机壳的焊接变形,焊后各项指标达到设计要求。     

N06600镍基管材的焊接工艺探析

介绍N06600材料的特点,通过有害气体对镍基材料焊接时的影响、等分析该材料的焊接性能。详细叙述N06600镍基管道的焊接工艺,如焊材的选择,焊封底焊接方法等,并提出提高焊接质量的措施。焊接流动性、焊接熔深坡口的选择,钨极氩弧     

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.