声发射缺陷检测技术的应用与发展

本文详细阐述了声发射这一新兴检测技术的原理和发展过程,论述了其在锅炉压力容器方面的应用。指出了声发射技术的发展方向。     

声发射技术在防喷器检测中的应用

简要介绍了国内声发射技术在防喷器检测的应用现状。总结了声发射技术检测的在用防喷器使用状况表,对不同型号的防喷器和使用时间不同的防喷器进行分析,统计出防喷器的使用状况规律。根据声发射的检测结果分析了防喷器的缺陷成因,为防喷器的继续使用和维修提供依据。声发射技术应用于防喷器的检测非常成功,最后提出了目前急需解决的问题和发展趋势。     

声发射技术在泄漏检测中的应用

通过对声发射泄漏检测的原理、机理和仪器设计等的研究,探讨了适合我国工业应用的声发射检漏技术,将价廉、便携、高效和操作方便的声发射仪器应用在工艺设备及管道泄漏检测上的可行性。     

声发射技术在锅炉泄漏检测中的应用

针对锅炉所存在的泄漏缺陷,提出了一种声发射逐点监测方法,然后结合声发射信号幅度历程和波形频谱分析法,通过现场检测实例验证了该方法用于锅炉泄漏缺陷声发射检测的可行性与准确性。     

声发射技术在覆土油罐检测中的应用

为了给油库管理者制定油罐检修计划提供科学依据,对覆土油罐进行了声发射检测试验。探讨了覆土油罐声发射技术的应用方法和数据分析,得到了试验油罐底板腐蚀程度和声发射信号能量分布的情况。试验结果表明,声发射技术能够对覆土油罐底板的腐蚀状态做出判断,且静压检测和升压检测都可以反映出覆土油罐底板声发射源的活度差异,并据此确定储罐维修的优先权。     

声发射技术在焦炭塔检测中的应用

为缩短检验工期与减少保温拆除费用,应用声发射技术对大型焦炭塔进行了检测,并采用常规无损检测方法对声发射检测结果进行了复验。结果表明,声发射检测与常规无损检测方法发现的缺陷位置具有良好的对应关系,证明声发射检测方法在焦炭塔缺陷检测中的可行性和有效性,为类似大型石化设备声发射检测提供了重要参考。     

常压储罐声发射检测技术

声发射检测技术可用于常压储罐腐蚀评价。讨论了常压储罐中声发射信号产生的机制和传播过程,试验研究了液体介质中声发射源的定位、波速的计算及声发射信号的衰减规律,提出了声发射信号的分析方法以及结果评价方法。指出由于信号传播路径的不确定,使定位分析较困难,而从每个通道单位时间的撞击数来判断更有实际意义,并给出了工程实例。     

压力容器无损检测--声发射检测技术

声发射技术是20世纪60年代开始,目前逐步成熟的一种无损检测方法,已被广泛应用在压力容器检测和结构的完整性评价方面。文中简要介绍了国内外压力容器声发射检测的发展史和现状。给出了压力容器用钢的声发射特性和压力容器声发射检测方法,综合分析了国内外压力容器声发射检测的标准、仪器和应用进展。最后指出了压力容器声发射检测的发展方向,即在线监测、声发射信号的模式识别和人工神经网络模式识别分析。     

Frequency response of transducers used in acoustic emission testing of concrete

This paper describes two methods for calibration of the frequency response of transducers used in acoustic emission testing of concrete. The first uses two transducers to be calibrated coupled back-to-back. One of the transducers is excited by an input signal. The frequency response of the transducers is then deduced from analysis of the output signal. Two types of excitation may be used: sinusoidal excitation, which makes it possible to obtain the response point by point, and impulse excitation, which gives the frequency response directly. The second method uses the breaking of a pencil lead on the transducer face. The response obtained must then be corrected. Three types of transducers, used in specific applications for acoustic emission testing of concrete, are then characterized by these methods.     

声发射在形状记忆合金研究中的应用

介绍了声发射（AE）法研究形状记忆合金的原理和基本方法，大量研究结果表明，通过检测形状记忆合金的AE信号，分析AE信号的特征参数，可研究和评价温度和应力诱发马氏体相变，了解其马氏体相变过程及其特点，进而对作为AE源的形状记忆合金本身的性能和状态进行评价，作为一种动态无损检测技术，声发射对研究形状记忆合金智能材料和结构起着重要作用。     

Determination of cracking resistance of thermal spray coatings during four-point bend testing using an acoustic emission technique

An acoustic emission (AE) technique was used for the determination of the onset of cracking of thermal spray self-fluxing NiCrFeBSi coatings under tensile loading using a 4-point bend testing apparatus. These coatings were flame sprayed on 42CrMoS4 cylinders having different diameters. Two different post-treatment fusing processes, induction, and flame fusing, were used. Along with the investigations of the effect of cylinder diameters and fusing processes onto the cracking resistance of the coatings, the effect of the same two parameters on the residual stresses was also investigated. Results show that, independently of the diameter of the cylinder, the flame-fused coatings possess a higher cracking resistance than their induction-fused counterparts, i.e., that the strain to fracture is higher for the flame-fused coatings. A correlation between the strain to fracture and the residual strain in the coatings has been established. This study points out that the combination of an AE technique with a bending test apparatus shows some major benefits to obtain important information on the relative ductility of thermal spray coatings.     

高压汽包用13MnNiMoR厚板的试制

通过化学成分设计及采用合理的轧制、热处理工艺,利用细晶强化、固溶强化、析出强化等手段,南阳汉冶特钢有限公司开发了150mm厚 13MnNiMoR容器板。性能检测结果表明：钢板组织为回火贝氏体+少量铁素体,钢板性能满足标准要求且富裕量较大。     

裂纹尖端塑性区的声发射特性研究

对裂纹尖端形成塑性区时产生声发射信号的累计数与应力强度因子的关系进行研究。运用线弹性断裂理论和弹塑性断裂理论进行了分析,得出累计数在小范围屈服时与应力强度因子的4m次方成正比,在大范围屈服时与应力强度因子的2m次方成正比。对碳钢和不锈钢的单边切口试样进行了拉伸声发射监测实验,实验测得大范围屈服时,比例系数分别为0.333和0.183,m值为0.5。     

Acoustic emission testing of steel cylinders for the storage of natural gas on vehicles

Acoustic emission testing for the periodic inspection of steel cylinders used for the storage of natural gas on vehicles was investigated. Normal refuelling pressurization does not produce adequate emission to enable structural integrity assessment. Detection of cracks through 15% or more of the side wall is feasible using overpressurization to 33% above the nominal refuelling pressure. A methodology was developed to distinguish between general corrosion product signals and those primarily associated with cracks. The effects of test interruption and the rate of cylinder pressurization on acoustic emissions were examined. The test method involves the application of one conditioning pressure cycle followed by one overpressure cycle. The sensitivity of the test method is adequate to permit an inspection interval of five years in service.     

Detection of fatigue crack propagation with acoustic emission

Since its inception, acoustic emission has held great promise as a tool for detection and evaluation of damage in structures. Of particular concern is the occureence of fatigue manifested by the processes of crack initiation followed by crack growth to failure. Early research related acoustic emission parameters to physical variables, including load, stress, pressure etc. causing damage. In this paper, relationships relating acoustic emission to fatigue crack growth are developed. Acoustic emission equations, similar to Paris' law, are derived which allow determination of the stress intensity factor and the crack growth rate. These principles are embodied in a second-generation system which automatically and continuously determines these parameters. The approach is applied in the laboratory as well as to structures including bridges, air frames and transmission towers for electrical power.     

蒸汽发生器管板与管孔密封焊缝的渗透检测

介绍了蒸汽发生器管板与管孔密封焊缝的渗透检测工艺及操作,对常见的密封焊缝渗透检测的缺陷进行了分析,可为国内核岛主设备管板与管孔密封焊缝的渗透检测及质量控制提供经验,供同行参考.     

管道电弧声发射特征采集系统设计

鉴于焊接电弧声信号中蕴涵着丰富的焊接状态信息,是焊接质量监控重要的源信号,而管道结构特征为电弧声发射信号在管内低噪声传播创造了条件。设计了管道电弧声发射采集硬件系统,主要由传感器、信号适配电路、数据采集卡和一体化工作站组成。采用图形化虚拟仪器编程语言LabVIEW,通过封装功能模块及调用硬件驱动的动态链接程序,设计了一套采用中断触发方式进行高速数据采集的电弧声发射软件系统。结果表明,该系统不仅能实现对电弧电压、焊接电流和电弧声发射信号的高速实时同步采集,并可将采集结果图形化显示,很好地解决了实时图形绘制难的问题,为进一步研究管道TIG焊接电弧声发射机理创造条件。