特种设备用激光熔化沉积钛合金构件的超声检测
Ultrasonic testing of laser melting deposited titanium alloy for special equipment
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摘要: 特种设备行业对激光熔化沉积钛合金构件的承压能力、安全性能具有较高要求。由于激光熔化沉积的特殊制造工艺,成型的材料具有较高的多晶散射和衰减特性,严重影响了检测信号的信噪比。针对这一问题,提出了一种基于归一化互相关的超声回波信号处理方法。根据参考信号的互相关系数对超声波全波数据进行归一化和重建,以抑制噪声并提取大深度的弱回波信号。针对预埋缺陷的TC11钛合金试件进行了超声水浸C扫描试验,用归一化互相关方法处理收集到的回波信号,并对底部和缺陷回波进行成像。试验结果表明,归一化互相关方法可以提高传统单声道超声检测方法对大厚度和复杂声学特性的钛合金部件的检测能力。Abstract: There are high requirements for the pressure-bearing capacity and safety performance of titanium alloy components by using laser melting deposition in the field of special equipment. Due to the special manufacturing process of laser fusion deposition, molded titanium alloy material has a high polycrystalline scattering and attenuation, which seriously affects the detection of the signal-to-noise ratio. A method for processing ultrasonic echo signals based on normalized cross-correlation was proposed in this paper for solving the problem. The ultrasonic full-wave data was normalized and reconstructed according to the correlation coefficient of the reference, and to suppress the noise and extract the weak echo signals at large depths. For pre-buried defective TC11 titanium alloy specimens, ultrasonic C-scan test was performed, and the collected echo signals were processed by normalized cross-correlation method, and the bottom and defect echoes were imaged. Results showed that the normalized cross-correlation method can improve the detection capability of conventional mono-ultrasonic inspection methods for titanium alloy components with large thickness and complex acoustic properties.