厚壁容器筒体管座焊缝超声检测的声程计算

介绍了厚壁容器筒体管座焊缝超声检测时一次声程计算的推导,为借助计算机进行不同位置的一次声程计算建立了数学模型。     

锅炉和压力容器管座角焊缝的无损检测

分析了目前对管座角焊缝检测存在的不足。介绍了对管座角焊缝表面质量及内部质量进行无校检测时适用的各种方法，指出合理选用检测方法是角焊缝检测质量的重要保证。     

薄板角接焊缝超声检测的参数确定

通过对薄板角接焊缝内的体积型缺陷和面积型缺陷的检测试验，阐述了角接焊缝数字超声检测的方法，以及各种探头的技术参数的确定，从而得出此种探测方法用于实际薄板角接焊缝探测过程，有利于减少盲区，防止漏检。     

油罐焊缝缺陷的超声相控阵检测

超声相控阵技术作为新型的无损检测技术已应用于油罐缺陷检测领域。针对实际焊缝中可能存在的裂纹、气孔、未熔合和未焊透等缺陷,设计制作了包含不同缺陷的焊缝试块。通过设定超声相控阵的声束角度、焦距位置和焦点尺寸等参数,可清晰检测到焊缝内部缺陷,并能较准确地判断内部缺陷的位置和大小。但相控阵技术对被检件表面要求较高,且需要制作多种试块。     

角焊缝未熔合的超声检测

介绍角焊缝未熔合的超声检测工艺,针对笔者单位目前某产品生产制造过程中存在的问题（未熔合的定性较为困难）进行解剖分析,从而优化检测工艺,更好地对缺陷进行定位、定性并对焊缝质量进行有效的控制。     

P91钢焊缝蠕变的非线性超声检测

分析了金属材料蠕变过程中的非线性应力-应变关系,指出在蠕变超声检测过程中存在非线性波动现象.讨论了使用脉冲超声实现非线性检测的方法,即利用超声检测信号高频段与低频段的能量之比作为非线性的表征.分析了衰减对非线性检测的影响,并根据频率-衰减关系对非线性参数的计算方法做出了修正.应用该方法对不同蠕变状态的P91钢母材及焊缝热影响区进行了检测.结果表明,非线性参数随蠕变时间的增加呈上升趋势;该方法可以有效区分同一材质的不同蠕变状态,可以作为P91钢焊缝蠕变程度相对性检测的有效方法.     

全自动相控阵超声检测技术在环焊缝检测中的应用

全自动超声波检测在国外已大量应用于长输管线的环焊缝检测 ,且已成为一种趋势。与传统手动超声检测和射线检测相比 ,其在检测速度、缺陷定量准确性、减少环境污染及降低作业强度等方面有着明显的优越性。加拿大Ｒ/ＤＴｅｃｈ公司生产的ＰｉｐｅＷＩＺＡＲＤ相控阵超声检测系统是专用于长输管线环焊缝的检测设备。该系统由数据采集单元、脉冲发生单元、电机驱动单元、相控阵探头、工业计算机和显示器等组成。系统在ＷｉｎｄｏｗｓＮＴ界面下运行ＰｉｐｅＷＩＺＡＲＤ操作软件 ,完成对焊缝的线性扫查、实时显示和结果评判。以下是笔者用该系…     

三通焊缝的超声检测

根据三通焊缝的结构特点，结合实际工作经验，总结分析了三通焊缝的超声检测方法。     

带凸面声透镜的相控阵超声检测技术

带凸面声透镜的相控阵超声技术通过设置与工件表面曲率相匹配的凸面透声楔块来改善平面探头与凹面工件的界面耦合效果,同时,凸面声透镜在圆周方向上有一定的声束聚焦作用,可有效降低凹界面的耦合损失对检测造成的不利影响.将带凸面声透镜的相控阵超声技术应用于承压设备插入式管座角焊缝的质量检测,结合实时成像技术,可以直观地显示缺陷的位...     

焊缝缺陷超声定量检测方法探讨

按断裂力学分析,焊缝缺陷在壁厚方向上距上表面距离P_1、距下表面距离P_2及自身高度h值直接影响其裂纹当量尺寸(?)的大小,相对而言,缺陷的长度等尺寸对(?)影响较小,因此P_1,P_2及h值的准确检测对缺陷监护控制和压力容器安全分析等具有极为重要的意义。常规检测方法对P_1,P_2及h值均未给予足够的重视。因此,探讨针对危害性面状缺陷的P_1,P_2及h值的定量检测很有必要。     

Application of modeling techniques for ultrasonic austenitic weld inspection

After a brief discussion of the fundamental equations of elastic wave propagation in anisotropic (transversely isotropic) materials and their basic solutions in terms of plane waves and Green functions, we point out and demonstrate the usefulness of Huygens’ principle in conjunction with the results obtained by the numerical Elastodynamic Finite Integration Technique (EFIT)-code for an intuitive physical understanding of ultrasound propagation in austenitic steel. EFIT is briefly explained and then validated against a weld transmission experiment; applications to pulse echo simulations for various canonical and real-life geometries and structures with and without backwall entering notches are to follow. Further, we have been able to confirm the existence of the second qSV-wave, as predicted by plane wave theory, through EFIT-modeling as well as experiments.     

Rapid ultrasonic C-scan test for spot welding based on image interpolation

In this paper, ultrasonic C-scan test of spot welds for stainless steel has been studied. It is concluded that large scanning step length contributes to high testing efficiency, however, the low-resolution C-scan image generated cannot be used to assess spot welding quality reliably. Based on bicubic image interpolation, the C-scan image in low resolution with the large step length 1 000 ~xm is subdivided and reconstructed. By this means, the C-scan image resolution is greatly enhanced and testing results obtained are satisfactory, realizing rapid assessment of spot welds. The results of rapid ultrasonic C-scan test fit the actual metallographic measured value well. Mean value of normal distribution of error statistics is O. 006 67, and the standard deviation is O. 087 11. Rapid ultrasonic C-scan test based on image interpolation is of high accuracy and excellent stability.     

高速列车车体服役状态残余应力超声波法无损测量及验证

焊接残余应力影响焊接结构可靠性.传统残余应力测量方法无法满足焊接结构服役状态下的应力测量,无法实现薄壁结构的应力测量.使用改进的超声波法焊接残余应力测量系统,对壁厚3.5 mm的薄壁高速列车车体残余应力实现了无损测量,测量过程实时无损快速.测量结果与有限元模拟和激光全息小孔法测量结果对比,超声波法测量结果可靠,且对试验结果进行了讨论分析.建立的超声波法应力无损测量系统为焊接结构服役状态在线可靠性评估奠定了基础.     

基于LBP-KPCA特征提取的焊缝超声检测缺陷分类方法

焊缝缺陷影响结构安全,缺陷定性是实现结构安全评价的重要基础.研究了一种基于一维局部二元模式（one-dimensional local binary pattern,1-D LBP）算法结合核主成分分析（kernel principal component analysis,KPCA）提取焊缝缺陷回波信号特征的方法.采用1-D LBP算法提取缺陷回波信号的LBP特征,通过KPCA对此LBP特征集进行主成分分析,选取贡献率之和超过90%的前N个主成分作为缺陷分类的特征向量,利用基于径向基核函数的支持向量机（support vector machine,SVM）实现了缺陷类型的自动分类.以夹渣、气孔和未焊透三类焊缝缺陷为对象,开展了缺陷特征提取及分类试验.结果表明,使用LBP-KPCA特征进行缺陷分类时,准确率达到96.7%,优于常规特征,为焊缝缺陷分类及无损评价提供了重要参考.     

Quantitative evaluation of micro-cracks using nonlinear ultrasonic modulation method

Nonlinear acoustic coefficients have a close relationship with structural cracks. A nonlinear ultrasonic modulation method for micro-crack quantitative evaluation is developed. The influence of phase threshold on the crack evaluation is discussed. Ultrasonic modulation using a unilateral incentive model is applied to the quantitative evaluation of micro-cracks for different specimens. The experimental results indicate that the method can be beneficially applied for micro-cracks detection. A proper phase threshold can improve the reliability of the method based on nonlinear ultrasonic modulation. The presented modulation factor can be used to quantitatively evaluate the structural cracks, and it is suitable for small-crack quantitative evaluation.     

基于频率—相位编码信号激励的焊缝超声检测分析

焊接结构在工业领域的应用十分广泛,常应用于复杂结构中,对焊接质量要求较高,需要高时间分辨率的超声检测方法检测焊缝内部缺陷.为了提高检测结果的时间分辨率,将雷达领域的编码激励与脉冲压缩技术引入焊缝检测中,提出一种基于幅度加权频率调制的相位编码激励检测方法,该方法的激励信号为幅度加权的线性调频信号与巴克码信号的复合.结果表明,相同带宽下,与线性调频信号和巴克码激励的检测结果相比,所提出的激励方法检测结果的时间分辨率较高,同时,有效降低了调频带宽对检测结果的影响.     

Cr-Mo-V钢焊接接头塑性损伤的非线性超声评价

采用非线性超声纵波技术对汽轮机转子钢30Cr2Ni4MoV焊接接头不同程度塑性损伤试样进行了超声非线性信号的检测.结果表明,超声非线性参数随着焊接接头试样塑性应变或损伤的加剧而显著上升;对于同一加载情况下的试样,与母材和热影响区相比,焊缝中心的非线性参数变化最大.同时,利用透射电子显微镜对不同塑性应变焊缝中心微观结构进行观察,发现位错密度的增加是导致非线性参数随着塑性应变增大的主要原因.     

An ultrasonic testing method for detecting delamination of sprayed ceramic coating

The adhesion strength of thermal sprayed coatings is relatively low, and they sometimes tend to delaminate from the substrate during operation. In particular, sprayed ceramic coatings for thermal barriers, such as ZrO₂, often delaminate because of thermal shock; therefore, ceramic coatings are often submitted to thermal shock tests. A nondestructive inspection method using ultrasound to detect the delamination of sprayed coating was proposed. In this study, a coating model was made with acrylic plates, and an ultrasonic test was applied to investigate the precision of detecting delamination by the ultrasonic testing method. Results indicate that delamination more than 1mm in diameter can be detected by the ultrasonic testing method. Moreover, the delaminating process of sprayed coatings under thermal shock tests can be detected by this method.     

基于时频分析的奥氏体焊缝超声检测信号处理

对奥氏体焊缝超声检测信号处理方法进行了研究.提出一种基于匹配追踪和小波变换两种时频分析方法的信号处理方法,分别从能量和频率的角度区分缺陷信息和材料散射噪声,提高超声检测回波的信噪比.为了验证此方法的有效性,建立了超声检测试验系统,对53 mm厚焊缝试块进行检测试验,采集了含有大量材料噪声的实际检测信号.选用sym8小波...