X 射线缺陷信息传递及其注解

引言众所周知,人们在阐述 X 射线透照的基本原理时,引入射线的衰减律公式 J=Joe~-μ~A,对被透照构件(本文指高压容器焊缝)的成象机制加以说明;并用照相过程理论对构件的健全部位和缺陷部位的厚度差异,导致俘获光量子能力的强弱,最终形成明暗相间的缺陷图形进行解释。这是人们长期以来所沿用的理论依据。     

奥氏体不锈钢半圆管夹套焊接工艺要点探讨

在化工容器和设备上采用奥氏体不锈钢焊接半圆管夹套一般具有较高要求,通过实际生产中对于不同焊接工艺的应用,本文结合奥氏体不锈钢制作化工容器和设备上焊接半圆管夹套焊缝性能要求,针对不锈钢逐段冷成形焊接在凸形封头上的半管盘管或者是整根对半剖分盘管焊接工艺要点,总结出对于此类焊缝的焊接工艺要点和焊缝检测与试验内容,同时该焊接工艺评定的做法和评价可以应用于类似焊缝.     

增大底片宽容度途径的探讨

本文通过对不等厚钢板焊缝的射线透照试验,指出了利用辐射场的偏斜效应,采用侧射线透照,并适当提高管电压,配合使用较厚的铅箔增感屏,以获得增大底片宽容度并提高底片灵敏度的有效途径。     

透照参数对灵敏度影响的讨论

本文以焊缝探伤为例,对X射线透照参数中的电压,焦距,射线投射角度,底片黑度等对灵敏度的影响进行了综合分析,并对这些参数的选择进行了讨论,指出了正确选择这些参数的重要性。     

射线技术在材料评价和材料缺陷评价方面的开发研究动向

1前言 射线透照试验是用X射线或γ射线等短波电磁波透过物体,通过检测透射率的差异获得试样内部信息的技术.射线透照试验缺陷检测法按摄像方法分为直接摄像法,.透视法和特殊摄像法等等.直接摄像法是在试样背面安放的X线胶片和显像板上显现出透过试样的X线强度的变化情况,根据其对比度或与对比度相对应的彩色图像判别材料内部存在的缺陷.     

换热管与管板角焊缝的射线检测研究

用普通便携式X射线机，采用特殊的透照技术，对换热管与管板角焊缝进行射线检测。     

增大底片宽容度途径的探讨

本文通过对不等厚钢板焊缝的射线透照试验，指出了利用辐射场的偏斜效应，采用侧射线透照，并适当提高管电压，配合使用较厚的铅箔增感屏，以获得增大底片宽容度并提高底片灵敏度的有效途径。     

管子-管板焊缝射线检测技术研究

介绍管子-管板焊接接头的射线检测方法。指出采用小尺寸Ir192射线源以向后透照的方式,并配有专用的滤光板和遮蔽板及灵敏度试样可以对焊缝的内部缺陷进行有效的检测,保证该类焊缝的质量。     

一种基于工控机控制+PLC的自动化柱焊缝检测装置研究

X射线无损探伤是焊接质量控制的重要方法 ,一些管状零件仍采用胶片透照的方法来检测。本文介绍了基于工业计算机与PLC在自动化柱焊缝检测装置中的关键技术研究,其涉及信号检测与处理,基于LabView的人机交互界面,PLC组态分析及相关研究。     

基于模糊推理的X射线图像焊缝提取

对于航天、管路、压力容器等重要焊接结构，X射线焊缝底片的检测要求较高，工作量大，且检测结果直接受检测者主观因素的影响而不稳定。为了提高评片结果的规范性和一致性，实现焊缝底片评定过程的自动化很有必要。本文提出一种基于模糊理论的焊缝识别方法，应用模糊推理对图像逐线进行处理，根据空间对比度和空间方差确定焊缝边缘。使用该方法对一百多张铝合金焊缝X射线底片进行焊缝识别，成功提取出了所有的焊缝。     

Improving the analysis of small precipitates in HSLA steels using a plasma cleaner and ELNES

The change from producing high strength low alloy (HSLA) steel sheet by conventional thick slab casting to producing it by direct charged thin slab casting causes a major change in the evolution of the precipitation. A key area of interest is the composition of the sub-10nm precipitates used to produce dispersion hardening. Carbon extraction replicas are frequently used to study precipitates in steels and other metals. When used with annular dark field imaging, this technique gives high contrast images of the precipitates while the thin carbon film adds little background or additional characteristic signals to either electron energy loss spectra or energy dispersive X-ray spectra. The method has the additional major advantage of removing the ferromagnetic matrix when studying HSLA steels. However, when the precipitates contain carbon, the C K-edge is dominated by the contribution from the amorphous carbon film. A plasma cleaner can be used to thin this carbon film to approximately 0.5 nm or less and then the contribution from the carbon in the precipitate can be separated from that in the carbon film using the electron energy loss near edge structure. A similar approach can be taken to separate the oxygen content of the precipitate from that of oxides formed from low-level impurities in the amorphous carbon during the plasma thinning process. In most cases, the precipitate studied here contained little or no oxygen even for the smallest sizes examined (approximately 4 nm). The precipitates contain mainly nitrogen with little carbon. For some compositions, the precipitates are clearly sub-stoichiometric.     

利用广角衍射仪对软X射线超薄膜的测量

利用X射线衍射,是目前国际上对超薄多层膜进行检测常用的方法之一,但只局限于双晶或小角衍射仪。本文利用的方法解决了广角衍射仪在低角区测量时由于样品放置误差所造成的衍射峰偏移和得不到衍射曲线的问题,从而使广角衍射仪得以应用在小角区测量。文中重点对测量曲线进行了分析,准确计算了多层膜的周期和单层膜厚度,并与测量值进行了比较,结果表明利用广角衍射仪测量膜厚是切实可行的。在目前我国X射线波段反射率测量装置还没有完善的条件下,利用X射线衍射仪对超薄膜的检测更显得格外重要。     

国内外关于低温压力容器设计理念的比较

通过对GB 150《压力容器》与ASMEⅧ-1以及EN 13445关于低温压力容器设计理念的对比,指出应用GB 150《压力容器》进行低温压力容器设计时应引起注意的地方。同时提出我国低温压力容器标准今后发展的基本思路。     

Heat transfer and pressure drop of a gasket-sealed plate heat exchanger depending on operating conditions across hot and cold sides

Journal of Mechanical Science and Technology - In a gas engine based cogeneration system, heat may be recovered from two parts: Jacket water and exhaust gas. The heat from the jacket water is often...     

真空度对Ni80Cr20薄膜中性度的影响

理论计算了Ni、Cr和Ni80Cr20三种材料的光学特性,确定了镍铬成份变化对Ni80Cr20的影响。在高低两个真空度条件下采用电子枪蒸发工艺进行了Ni80Cr20的镀膜实验,结果表明,低真空度时"薄"膜的中性度较好,而高真空度时"厚"膜中性度较好。采用X射线能谱分析发现"薄"膜铬含量高于膜料,而"厚"膜更高,高真空度薄膜略有氧化,而低真空度氧化更严重。从残余气体和蒸发方式方面分析了镍铬成份差异的原因,再结合氧化对薄膜特性的影响,确定了不同真空度薄膜中性度差异的原因。     

X射线无损探伤技术在变电站运行状态GIS检测中的应用

现有变电站运行状态GIS检测工作,难以确保所有高压输电站都能实现每年一次的检修工作,因此研究了X射线无损探伤技术,并将其应用在变电站运行状态GIS检测中。预先设计了X射线防护装置,屏蔽高压电磁脉冲对X射线机的干扰;在此基础上,构建X射线相机模型,并选择合适的管电压、管电流,明确工件对比度和成像板灵敏度;通过几何变换、灰度变换、图像平滑和阈值分割手段,处理GIS检测图像,实现检测变电站运行状态。实验测试结果可知,当施加电压超过150kV时,无防护装置的X射线机被高压脉冲干扰,无法显示检测结果;而有防护装置的测试组中,当施加电压超过330kV时,X射线机依旧可以显示GIS检测结果。可见此次应用的X射线无损探伤技术,在防护装置的辅助下,可以更好地实现变电站运行状态检测。     

带夹套换热器的制造和检验

为某公司制造的带夹套固定管板换热器 ,是生产聚酯成套设备中的关键设备 ,经过对不同规格同类产品的多次制造 ,总结出了一套成熟的制造和检验工艺 ,本文以其中一台为例 ,结合产品的特点 ,重点阐述了该产品的制造工艺和检验方法     

The Compatibility of Crankcase Lubricant–Material Combinations in Internal Combustion Engines

Recent advances in engine technology have seen the introduction of new materials and surface coatings leading to an overall reduction in weight and improved durability. However, the lubrication requirements of these materials are not fully understood. In this paper the lubrication of traditional Cr-bearing steel and Al–Si alloy-based components is investigated using two fully formulated lubricants. These two lubricants have the same viscosity grade and phosphorous levels but differing base stock and detergent systems. A pin-on reciprocating plate configuration was used for the tribological experiments and analysis was performed using X-ray Photoelectron Spectroscopy (XPS), Environmental Scanning Electron Microscopy (ESEM) and Energy Dispersive X-ray analysis (EDX). It has been found that in a completely ferrous-based system, fully formulated lubricants are effective in reducing wear and friction and a relatively thick anti-wear film is formed. In partially aluminium systems the fully formulated lubricant is less effective and a thin (and therefore unstable) anti-wear film is formed when a cast iron pin is rubbed on the Al–Si alloy plate. In completely non-ferrous systems the wear film is absent. In this paper the fundamental aspects of the film formation as well as the practical aspects of the results will be discussed.     

Effect of Radiant Energy on the Formation of Optical Image in X-Ray Inspections

Digital radiography is currently a genuine alternative to the laborious and uneconomical method of X-ray diffraction in nondestructive testing. The processes of forming optical images on a radiographic film and on a flat-panel detector are different. The input action on a detector, whether a radiographic film or a digital transducer, is the so-called radiation image, the X-ray radiation generated by an X-ray tube and transmitted through a test object. The object attenuates radiation depending on its own thickness and material density. The main parameters of the radiation image are its contrast, definition, and signal-to-noise ratio (SNR). In order to achieve the most efficient conversion of the X-ray image into an optical one, one needs to choose the optimum combination of the listed parameters depending on which detector is being used. In this study, theoretical research and practical evaluation of its results have been carried out. Conditions have been determined for the best adaptation of a radiation image to the employed detector that ensure the prescribed quality indicators of the optical image of the test object. Results of the research that was carried out within the framework of scientific field 2.3 “Developing methods for automated nondestructive testing and the reliability of its results” (“Strategic directions of development of materials and technologies of their processing for a period of up to 2030”) are provided.     

Evaporation during preparation of unsupported thin vitrified aqueous layers for cryo-electron microscopy

Evaporation of water cannot be fully avoided when an unsupported thin vitrified film of an aqueous suspension is prepared for cryo-electron microscopy. This results in increasing concentration of solute which could affect the observed material. We have quantitatively studied this effect by measuring the contrast of polystyrene spheres in a metrizamide solution. The drying effect is generally negligible when specimens are prepared on a hydrophilic perforated support but it is frequently important when hydrophobic films are used instead. A flow of humid air, double blotting with minimal exposure of the thin liquid film to the atmosphere, or an automatic plunger optimizing the blotting conditions are simple methods for reducing drying effects. With this third device acting on a hydrophilic supporting film, the increase of solute concentration is limited to less than 20%.