PDF(Pubmed)
Abstract：
The identification of slag inclusion defects in welds is of the utmost importance in guaranteeing the integrity, safety, and prolonged service life of welded structures. Most research focuses on different kinds of weld defects, but branch research on categories of slag inclusion material is limited and critical for safeguarding the quality of engineering and the well-being of personnel. To address this issue, we design a simulated method using ultrasonic testing to identify the inclusion of material categories in austenitic stainless steel. It is based on a simulated experiment in a water environment, and six categories of cubic specimens, including four metallic and two non-metallic materials, are selected to simulate the slag materials of the inclusion defects. Variational mode decomposition optimized by particle swarm optimization is employed for ultrasonic signals denoising. Moreover, the phase spectrum of the denoised signal is utilized to extract the phase characteristic of the echo signal from the water-slag specimen interface. The experimental results show that our method has the characteristics of appropriate decomposition and good denoising performance. Compared with famous signal denoising algorithms, the proposed method extracted the lowest number of intrinsic mode functions from the echo signal with the highest signal-to-noise ratio and lowest normalized cross-correlation among all of the comparative algorithms in signal denoising of weld slag inclusion defects. Finally, the phase spectrum can ascertain whether the slag inclusion is a thicker or thinner medium compared with the weld base material based on the half-wave loss existing or not in the echo signal phase.
摘要：
焊缝中夹渣缺陷的识别对于保证焊缝的完整性至关重要。安全,和延长焊接结构的使用寿命。大多数研究集中在不同类型的焊接缺陷，但是，关于夹渣材料类别的分支研究是有限的，对于保障工程质量和人员福祉至关重要。为了解决这个问题，我们设计了一种使用超声波检测来识别奥氏体不锈钢中包含材料类别的模拟方法。它基于在水环境中的模拟实验，和六类立方体标本，包括四种金属材料和两种非金属材料，被选择来模拟夹杂物缺陷的炉渣材料。采用粒子群优化的变分模态分解对超声信号进行去噪。此外，利用去噪信号的相位谱提取水渣试样界面回波信号的相位特征。实验结果表明,该方法具有分解适当、去噪性能好的特点。与著名的信号去噪算法相比,在焊渣夹杂物缺陷信号去噪的所有比较算法中，该方法从具有最高信噪比和最低归一化互相关的回波信号中提取出最低数量的本征模式函数。最后,相位谱可以基于回波信号相位中存在或不存在的半波损耗来确定熔渣夹杂物与焊接母材相比是较厚的还是较薄的介质。
