超声波检测斜Y形焊缝打底层裂纹对比性试验

裂纹类缺陷的有效检出是无损检测面临的主要任务。对于某新型船体结构关键Y形焊缝节点,即使根据检验规格书进行检测,也可能存在打底层裂纹漏检的风险。本文以检测灵敏度为技术评价指标,对Y型全熔透焊缝采用FCAW-CO_2焊接方法的焊接质量进行了综合评价。通过对比超声波检测、目视检查和渗透检测结果,优化了无损检测工艺,使得表面检测未发现的打底层裂纹被超声方法有效检出,最终确保焊缝的焊接质量。     

焊缝根部缺陷的综合检测

通过综合应用无损检测技术,对船体分段合拢焊缝打底层焊道出现的异常超声波反射信号进行分析及评价。以射线、磁粉等检测手段分析了异常信号所对应的缺陷性质及定性可靠性,为根部微裂纹缺陷检测和提高焊接工艺规范提供了依据。     

超临界锅炉过热器/再热器用T23钢焊接裂纹的磁粉探伤

针对超临界直流锅炉过热器、再热器钢所采用的新型耐热钢T23在使用过程中出现的焊接接头裂纹缺陷,分析了射线检测和超声检测的局限性,并根据其铁磁性材料特征及缺陷特点,确定对该类焊接接头采用磁粉探伤工艺,检出含裂纹缺陷焊接接头302只,缺陷检出率显著高于射线探伤、超声探伤方法。检测结果表明对T23钢焊接裂纹缺陷采用磁粉探伤检测方法,工艺可靠且方法简便高效,也为其他类似结构铁磁性材料焊接接头探伤提供了借鉴和参考。     

焊接裂纹无损检测方法

焊接裂纹是焊接常见的缺陷之一,及时检出裂纹是保证焊接质量的前提。无损检测方法已经应用到制造业的许多领域。本文从常规无损检测和非常规无损检测两方面分析了焊接裂纹的无损检测方法,阐述了各种无损检测方法的原理与现状。比较了各种方法的优缺点,同时论述了各种方法的适用对象,并对裂纹无损检测技术进行了展望。     

船用大尺寸刚性试板抗裂性试验方法及应用

介绍了俄罗斯船用大尺寸刚性试板抗裂性试验的结构和评价方法。用该方法进行的船用焊接材料的焊接抗裂性评价应用的结果表明，该试板结构和实船的船体外壳相似，能够暴露出实船焊接可能出现而无损检测方法所不能检测到的细小的横向裂纹，其裂纹敏感性高，可靠性好。     

基于FGT-FBP重构算法的焊接缺陷检测

针对焊接过程产生的缺陷,提出一种磁光成像传感的模糊灰度变换和滤波反投影(FGT-FBP)重构检测方法. 研究焊接缺陷的几何特征,通过分析裂纹和未熔合两种不同焊接缺陷在交变磁场励磁下的磁光成像特征,设计模糊规则,对磁光图像进行模糊灰度变换. 增强磁光图像对比度,使焊接缺陷形态趋势可视化,实现描述磁光成像焊接缺陷细节的无参考型图像评估方法. 对FGT处理的焊接缺陷磁光图进行旋转投影,并经过快速傅里叶变换和改进的滤波器进行滤波去噪,消除伪影后进行反投影变换实现焊接缺陷图像的重构. 利用滤波反投影重构算法进行去噪,可有效突出焊接缺陷特征. 最后结合阈值分割和边缘检测实现焊接缺陷检测. 结果表明,该方法能较准确检测裂纹和未熔合两种焊接缺陷.     

超级奥氏体不锈钢904犔焊接裂纹渗透检测及成因分析

采用液体渗透检测ⅡC-d(溶剂悬浮显像剂),有效检测超级奥氏体不锈钢904L在焊接过程中产生的焊接裂纹,返修时采用同样方法检测缺陷的去除,保证了焊接质量.同时对焊接裂纹的产生原因进行粗浅分析.     

超级奥氏体不锈钢904L焊接裂纹渗透检测及成因分析

采用液体渗透检测ⅡC-d（溶剂悬浮显像剂），有效检测超级奥氏体不锈钢904L在焊接过程中产生的焊接裂纹，返修时采用同样方法检测缺陷的去除，保证了焊接质量。同时对焊接裂纹的产生原因进行粗浅分析。     

焊接裂纹金属磁记忆信号的神经网络识别

金属磁记忆检测技术是一种新型的利用铁磁材料内在信息对材料进行检测和评价的无损检测方法,对裂纹类缺陷进行早期检测具有潜在的优势.利用小波包分析技术,对水压试验条件下API 5L X70管线钢焊缝中有无焊接裂纹的金属磁记忆信号能量特征进行了分析,确定了焊接裂纹金属磁记忆信号的小波包能量特征,并利用其作为输入特征向量建立了BP(back propagation)神经网络,对焊缝中是否含有裂纹等缺陷进行智能识别.结果表明,利用小波包能量和神经网络技术可以较好的实现焊接裂纹的识别.     

金属磁记忆在焊接缺陷检测领域的研究现状及发展

金属磁记忆检测技术是一种新型的无损检测方法,它具有能够对焊接结构中的微观缺陷进行早期诊断,防止突发性破坏事故发生的潜在优势,在焊接缺陷检测领域具有广阔的发展前景,被认为是迄今为止能够对材料的内部损伤进行早期诊断的惟一可行的无损检测方法.文中首先对金属磁记忆检测技术进行了简要的介绍,随后指出了该技术在焊接裂纹检测方面的独特优势.并与传统焊接缺陷检测方法进行了比较,然后就其在焊接检测领域的研究和应用进行了分析.最后指出了金属磁记忆检测技术在焊接检测领域的发展方向.     

焊缝质量无损检测评定最新国际标准介绍

对电弧焊接缺陷用无损检测进行质量评定的最新国际标准EN25817(同ISO5817)作了简要介绍和初步探讨.指出该标准对完善国内NDT质量评定验收要求,特别是填补角焊缝评定标准上的空白有重要参考价值.     

Anwendung von digitalen Bildverarbeitungsmethoden zur Interpretation von Korrosionsrissen auf Durchstrahlungsaufnahmen

Application of digital image processing to radiographs for the interpretation of corrosion cracks At in-service inspections in German nuclear power plants radiographic testing (RT) methods had been applied at a larger scale after cracks had been detected at the media affected inner surface of austenitic welds. The defect indications which follow the heat affected zone are difficult to evaluate in radiographs due to their lower contrast and the presence of undercut and large density differences which occur as a result of mismatches and excess penetration. For the interpretation of crack-like indications an evaluation procedure has been developed which applies digital image processing with a scanning system of sufficiant high spatial resolution (35 μm pixel width) and a grey-scale resolution of 12 bit (4096 grey levels). The procedure evaluates the half width, the maximum contrast of the RT indication and its length above a defined contrast threshold. This threshold takes into account the optical density, the signal-to-noise ratio and the wall thickness. By comparison with results from metallography of weld specimens for a large number of radiographic crack indications (true and false calls) criteria for a quantitative indication evaluation were definded.     

聚变反应堆焊缝超声检测标准比较

ITER(国际热核聚变实验堆)及CFETR(中国聚变工程实验堆)大型聚变装置的役前及在役无损检测分别参照标准RCC-MR-2007第3部分及标准NB/T 47013-2015执行。从适用范围、表面准备、探头参数规定、标准试块和对比试块、扫查方式、缺陷表征和验收等几个方面,将RCC-MR-2007中对接接头焊缝常规超声检测与NB/T 47013-2015中焊缝超声检测标准的相关内容进行对比,使设计人员更加深入地理解相应标准,并为设计优化提供参考。     

斜拉桥锚箱熔透角焊缝危害性缺陷分析和探伤方法介绍

从斜拉桥锚箱的重要性出发，通过对锚箱结构和受力情况的分析，初步判定锚箱熔透角焊缝容易产生的危害性缺陷，并对危害性缺陷的特征，结合现场锚箱焊缝探伤的实际结果，提出可靠、有效的探伤方法。     

大马力发动机活塞无损检测研究现状与进展

回顾了大马力发动机活塞发展历程及无损检测技术的应用情况。介绍了先进的电子束焊接活塞无损检测方法，包括活塞顶的超声波五探头水浸检测、活塞顶和活塞体的射线实时成像检测、电子束焊缝的超声波六探头水浸检测及工业CT检测、镶圈粘接质量的超声波检测等。论述了多种无损检测方法综合应用在电子束焊接活塞质量保证中的重要作用。最后对新型颗粒增强铝基复合材料活塞的无损检测技术作了展望。     

Modeling tools for ultrasonic inspection of welds

Developments in quantitative ultrasonic nondestructive testing (NDT) of welds require simulation tools for cost-effective research and engineering works. The present paper reviews the specific developments in modeling of weld inspection at the French Atomic Energy Commission (CEA), made in keeping with the general pattern of CEA in simulation studies of ultrasonic examination. Two models have been developed for several years at CEA for this purpose. One is dedicated to the computation of the ultrasonic field radiated by arbitrary transducers into pieces (possibly anisotropic and heterogeneous) under examination. We specifically discuss how the metallurgical structure and associated elastic properties of welds is taken into account. The other simulates a testing experiment. It accounts for the interaction of the beam with defects (within a piece made of isotropic material) and specimen boundaries and simulates the transducer scan over the piece for synthesizing images comparable with measurements. We specifically discuss the influence of the possible complex geometry of the back-wall of a weld. Examples of application are given. They demonstrate the usefulness of such modeling tools in ultrasonic NDT of welds to study and optimize testing configurations, and to help NDT experts to interpret actual data.     

欧洲射线检测最新标准评述

对欧洲标准化委员会制订的有关焊射线检测（ＲＴ）的方法和质量评定标准作一概略性评述,指出象质等级,胶片分类,黑度下限,缺陷测亮定深、定位、定性、定形的综合考虑,以及ＵＴ与ＲＴ要互补,角接焊缝缺陷评定的具体要求是有别于美、日标准的最大独特点。时缝无损检测与国际接轨有借鉴。     

Relation between mechanical microhardness and impedance variations in eddy current testing

According to the state of the art, eddy current testing (EC) has a strong application in defect detection. The sensitivity to characterize defects and other parameters can be improved by an optimal choice of probes and operation frequency.The work discussed here is a study to materials microstructure characterization and especially the heat affected zones (HAZ) near welds using eddy current techniques.These zones are sometimes brittle and characterized by a microstructure gradient. The aim of this work is to study by eddy current the behavior of such cases. For each damage mechanism, the authors have prepared series of samples. These specimens were tested using NDT methods based on magnetic and electric properties.Electric conductive material samples were made of Aluminum and steel and heated at different temperatures with variable exposure times.The aluminum samples were then exposed to corrosion using an electrochemical process.The applied NDT methods can characterize grain size changes, microstructure types, micro structural changes, hardness changes after thermal treatment.The objective of our work is to detect some metallurgical characteristics by non-destructive methods. The characterization of the microstructure modifications by eddy currents allows detecting mechanical and metallurgical parameters of materials.     

Finite element modelling of the scattering of ultrasonic waves by isolated flaws

A two-dimensional finite element model with absorbing boundary conditions has been developed to investigate the scattering of ultrasonic waves in infinite isotropic solids. The model is capable of showing a complex mode-conversion, when a short duration sinusoidal pulse interacts with a flaw. The emphasis is on narrow crack-like defects, cylindrical and spherical holes of size equal to the wavelength of the incident wave. The results, which are presented in the form of snapshots and scattering cross-sections, assist in understanding wave–flaw interaction, especially mode-conversion of the incident field and optimizing the ultrasonic NDT.