超声无损检测中的缺陷识别与噪声抑制

在传统的小波信号处理器基础上,根据解析小波变换能准确提取信号相位的特性,利用超声检测信号的相位信息,提出一种新的多缺陷识别与噪声抑制算法。该算法充分运用超声信号的时域、频率和相位信息,能检测多个具有不同频谱特性的缺陷。实验结果表明该算法不仅消噪性能好,而且提高了缺陷的纵向分辨率。     

Some Problems of Nondestructive Testing

Problems involved in selection of NDT techniques and determination of NDT operations required for hazardous facilities are discussed.     

Magnetic Method for Nondestructive Testing of Rebar in Concrete

It has been shown theoretically and experimentally that locally magnetizing rebar through a protective layer of concrete makes it possible to determine both the depth of the protective layer of concrete and the diameter of rebar based on stray magnetic fields regardless of the magnetic properties of steel that rebar is made of.

     

MF-23IM Magnetic Meter for Nondestructive Testing

The question of the necessity of examination of the magnetization and demagnetization processes is considered. The possibilities of an MF-23IM flaw-detection magnetic meter for carrying such examination are analyzed. Technical characteristics of the MF-23IM flaw-detection magnetic meter are given.The possibility of graphic mapping of the shape of magnetic field pulse is described.     

Metrological Assurance of Measurement Instrumentation Used in Magnetic Nondestructive Testing

Apparatuses manufactured by the industry for calibration of aw detectors, field meters, and gradient meters are described.     

基于漏磁检测的缺陷信号分析

为了应用漏磁检测技术检测管道缺陷,需要对缺陷信号进行分析。在漏磁检测原理的基础上,运用三种磁偶极子模型来描述各种表面缺陷。分析了缺陷参数对漏磁信号的影响。     

Differential Magnetic Method of Nondestructive Testing and Phase Analysis

In tests of roller-bearing, tool, and other sorts of alloyed steels, two magnetic char-acteristics must be measured in nondestructive tests of quenched structures, namely, the saturation magnetization and coercive force. In industrial conditions, a differential method is used in measuring these parameters with the help of an instrument built around an H-shaped applied electromagnet. The paper considers utilization of this magnet in nondestructive measurements of hardness of bearing components manufactured from the ShKh15, ShKh15SG, and 95Kh18 steels, pump elements from the ShKh15 steel, and components manufactured by sintering. A technique for estimating the content of residual austenite in the mentioned sorts of steel and martensite in steels of transitional sorts, in particular, Kh16N6, is described.     

Application of a Double Scanning Method in Ultrasonic Nondestructive Testing to Improve the Quality of Flaw Images

An algorithm for obtaining flaw images by a double scanning method for application in ultrasonic nondestructive testing, in which a radiator and a receiver move independently along parallel straight lines, is considered. A formula for reconstruction of flaw images is presented. The advantages and drawbacks of the double scanning method are discussed in comparison with the method of projection in the spectral space (PSS), which is also used for a coherent reconstruction of flaw images. The efficiency of the double scanning technique in suppressing the phantom images produced by transformed and rescattered pulses is shown in numerical and model experiments. The immunity of this method to the distortions introduced by an irregular measurement surface and the higher noise immunity compared to the PSS method are also demonstrated.     

Magnetic Properties of a Body as Nondestructive Testing Parameters of Tempering Quality of Quenched Steels (a Review)

The paper considers a nondestructive method for the monitoring of middle- and high-temperature tempering quality of steel workpieces with the carbon content higher than 0.3%. The method is based on measurements of the relaxation coercive force and the secondary residual magnetic induction of the body when remagnetization of the workpieces is carried out by means of permanent and alternating magnetic fields or by their superposition. It is shown that the possibility of this monitoring is ensured by the structural susceptibility of magnetic properties due to reversible displacements of domain walls, namely, the relaxation magnetization and magnetic susceptibility. The secondary residual magnetic induction of the matter and the relaxation coercive force of the matter cannot be used for this testing. The limiting workpiece shape factor below which this testing is possible is determined.     

一种基于磁真空泄漏原理的漏磁无损检测新方法

在磁折射的进一步推导与分析基础上形成一套缺陷磁真空泄漏原理.提出一种基于磁真空泄漏原理的漏磁检测新方法:清除较强的背景磁场,让被检测导磁构件体内磁通在缺陷处无反向背景磁压最彻底地泄漏到所创造的磁真空区域,形成最大化漏磁场并被置于该区域的磁敏元件所感应.采用有限元仿真与试验对该原理及其方法进行可行性论证.阐述该原理与方法的特性所在.磁真空泄漏原理及其方法使得缺陷漏磁场在空间范围和强度上均有所增大,可提高磁敏元件的探测提离距离,从而可实现真正的远距离非接触式漏磁探伤.另外,可消除或减少传统磁空气泄漏漏磁检测方法中由强的背景磁场所引起且一直存在的缺陷信息失真、磁噪声以及某些磁敏元件如霍尔的饱和不工作现象.磁真空泄漏原理与方法的提出与分析在促进漏磁检测方法的进一步应用的同时,也进一步地丰富和完善漏磁检测理论体系.     

Estimation of the Residual Magnetic Field Strength Inside a Pipeline after Testing by a Magnetic Flaw Detector

The residual magnetic field strength inside a pipeline after testing by a magnetic flaw detector is calculated. A portable device for demagnetizing local joint-pipe sections in carrying out repair-welding works is proposed.     

钢轨高速探伤检测系统中的伤损分析

本文介绍了一种新型钢轨高速探伤检测系统,给出了钢轨伤损分析软件的设计.实验结果表明在回转试验台上,检测速度达到了100km/h,并准确绘制出了钢轨伤损B型图.     

无损检测与评价在起重机械检验中的应用

首先介绍了无损检测与评价的定义及几种常用的无损检测方法,然后详细介绍了无损检测技术在各类起重机械检验过程中的应用,最后指出了无损检测技术的应用特点。     

On Reliability of Magnetic Nondestructive Testing of Metal Structure Using Simple Instruments

The paper summarizes the experience of efficient testing based on one or two magnetic parameters and the reliability of its results. Simple and portable magnetic structure analyzers for tests performed on production lines and in the field are described.     

Multipurpose Use of Magnetic Properties of Steels in Nondestructive Testing of the Quality of Heat-Treated Workpieces

The paper is devoted to calculation of expressions relating the hardness both of a series of low-alloyed steels and of high-chromium steels 14Kh17N2A, 20Kh13, 30Kh13, and 40Kh13 with their magnetic properties after quenching and subsequent tempering over a wide temperature range. Expressions relating the hardness of 60S2A, 50G, and U8 steels with reading of a MS-2 magnetic structuroscope are also calculated. A table containing tempering temperature intervals on which the coercive force, the relaxation magnetization, and the magnetic susceptibility vary monotonically is given for a series of steel grades. Limits of variation of the above-mentioned quantities and the hardness are also given.     

气化炉的无损检测

气化炉具有复杂的结构 ,按JB4 730— 94《压力容器无损检测》进行检测 ,本文对气化炉的无损检测做了全面的论述     

Handbook of Nondestructive Testing

Information

Handbook of Nondestructive Testing     

Inverse Problems of Ultrasonic Tomography in Nondestructive Testing: Mathematical Methods and Experiment

Russian Journal of Nondestructive Testing - The article is devoted to developing methods of ultrasonic tomography for nondestructive testing. The inverse problem of reconstructing velocity sections...     

生产过程中的硬度无损测量

本文叙述了超声波硬度计在生产工艺过程中的作用。介绍了超声硬度测量理论依据、工作原理和微电脑超声硬度计的结构原理、功能、特点。同时对超声波硬度计，在实际应用中造成测量误差的因素，进行了详细分析、论证，提出了改进方案。     

Evaluation of the Current Condition and the Residual Lifetime of Forming Rolls Using the Magnetic Method of Nondestructive Testing Based on the Coercive Force

The magnetic method on the basis of the coercive force H_c is proposed to use for estimating the current condition and the residual lifetime of forming rolls. Sixty rolls have been tested. It is shown that H_c increases almost twice in exploiting the roll from the beginning of the operation to reaching the limit of its lifetime. Results of observation of the degree of nonuniformity of the H_c distribution over the roll surface in the operation process are given. The results of investigation make it possible to optimize the path of each roll through the mill stands in order to avoid the stress concentration at the same depth of the roll operating (magnetic) coating in the roll change process. Using the magnetic testing method based on H_c makes it possible effectively to estimate the current condition of accumulation of the fatigue in the roll operating (magnetic) coating.