钢质承压设备用焊接材料技术条件的思考

对正在修订的《承压设备用焊接材料技术条件》标准中各主要观点与主要技术内容进行思考以及所总结的心得体会。主要内容有对目前钢制焊接材料标准的现状进行分析,论证了不能满足承压设备的要求;明确了承压设备用焊接材料技术指标;阐明目前钢制承压设备用焊接材料技术指标有很大的现实性以及我国承压设备用焊接材料标准的存在基础。     

浅析钢质承压设备用焊接材料技术条件

按现行国家标准颁布焊接材料是一种通用标准,它不能满足承压设备焊接所需的技术要求,基于特征和行业的压力设备的需求,焊接材料参考认证解释的必要性,制订承压设备用焊接材料的技术条件,而在当前的最初设想承压设备用焊接材料国家标准应适当提高。     

关于JB4747-200×《承压设备用焊接材料技术条件》修订的建议

目前所颁布的焊接材料国家标准是通用性标准,其技术要求已不能满足承压设备焊接的需要。本文根据承压设备的特点及行业的需要,参考船级社对船用焊接材料认证的做法,阐述了制订《承压设备用焊接材料技术条件》的必要性,并初步构想了承压设备用焊接材料在现行国家标准基础上应进行适当地提高。     

浅谈承压设备用焊接材料的入厂验收

目前国内用于制造承压设备的焊接材料没有统一的标准,因而造成了各个承压设备制造厂在焊接材料的入厂验收上存在着没有标准可依的现象,这对承压设备的制造存在一定的隐患。本文主要探讨了用于制造承压设备的焊接材料在入厂验收时的步骤及一些建议。     

承压设备用中外焊接材料标准对比研究

通过对锅炉压力容器用焊接材料的中、美、日和欧洲共86个国家标准，国内外6家著名厂商的726J焊条型号与牌号、555个焊丝型号和牌号、178个焊丝-焊剂型号与牌号进行了全面综合分析对比，总结了我国焊接材料特点，阐明我国承压设备用焊接材料技术要求，指出当前焊丝国家标准两个系统的危害，以及焊丝、埋弧焊焊材标准不保证熔敷金属化学成分与力学性能等的不足，对我国承压设备用焊材的需求及发展提出明确要求。     

承压设备用中外焊接材料标准对比研究(续)

通过对锅炉压力容器用焊接材料的中、美、日和欧洲共86个国家标准，国内外6家著名厂商的726J焊条型号与牌号、555个焊丝型号和牌号、178个焊丝-焊剂型号与牌号进行了全面综合分析对比，总结了我国焊接材料特点，阐明我国承压设备用焊接材料技术要求，指出当前焊丝国家标准两个系统的危害，以及焊丝、埋弧焊焊材标准不保证熔敷金属化学成分与力学性能等的不足，对我国承压设备用焊材的需求及发展提出明确要求。     

电站锅炉高端焊接材料应用现状

随着电站锅炉技术的发展,新产品、新结构、新材料的不断涌现对焊接技术提出了更高的要求。焊接材料事关焊接结构质量、安全生产及环境保护,也关乎新工艺、新方法的应用与推广,对电站锅炉整体性能及劳动环境保护的重要性不言而喻,因此,行业内对电站锅炉产品用焊接材料的要求一直很高。随着国家能源局NB／T47018《承压设备用焊接材料订货技术》标准的发布和实施,对电站锅炉用焊接材料提出了更高的要求。     

对"承压设备焊接工艺评定标准"的思考(一)

对正在制订的《承压设备焊接工艺评定》标准中各重要观点与主要技术内容进行思考，所总结的心得体会。主要内容有各类焊接工艺评定标准的目的、两个类型的焊接工艺评定，以及两类评定之间的区别与联系。本文还首次提出一些新思路、新观点，如母材、焊材分类细则以及标准以外材料分类要有分类报告佐证；通用的焊接工艺评定规定及使用方法；换热管与管板的焊接工艺评定是评定角焊缝厚度；气瓶焊接工艺评定是两个类型评定的结合，也可以分别评定。《承压设备焊接工艺评定》标准不仅适用于锅炉、压力容器（含气瓶），也适用于包括长输管道在内的压力管道。     

对"承压设备焊接工艺评定标准"的思考(二)

对正在制订的《承压设备焊接工艺评定》标准中各重要观点与主要技术内容进行思考以及所总结的心得体会。主要内容有各类焊接工艺评定标准的目的、两个类型的焊接工艺评定，以及两类评定之间的区别与联系。本文还首次提出一些新思路、新观点，如母材、焊材分类细则以及标准以外材料分类要有分类报告佐证；通用的焊接工艺评定规定及使用方法；换热管与管板的焊接工艺评定是评定角焊缝厚度；气瓶焊接工艺评定是两个类型评定的结合，也可以分别评定。《承压设备焊接工艺评定》标准不仅适用于锅炉、压力容器（含气瓶），也适用于包括长输管道在内的压力管道。     

成员国标准积极采用ISO标准——ISO承压用材标准评析之一

讨论了ISO承压用材料标准在承压设备及其用材料的国际贸易中的特殊地位。我国和一些国家的标准正在积极地采用相应的ISO承压用材料标准。     

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.