Application Note 002 操作说明002 Inspection of rubber lined metal pipes or vessels for disbonds 检测管道腐蚀或容器与其内衬橡胶脱胶
Motivation: Many metal pipes or vessels have rubber or other linings on the inside diameter for transport or mixing of certain fluids. There is a common requirement to be able to inspect the bonding between the metal and liner. 案例:许多金属管道或容器里有橡胶或其它内衬用以混合液体,一般需要检查金属和内衬橡胶之间的结合。
Principle: By using a transducer that can penetrate the rubber through the bondline, the amplitude of the interface can be measured with a flaw gate. Good bonding will attenuate the signal. A disbond will return a higher amplitude echo since the sound cannot now penetrate the rubber. 原理:我们需要选用一个能穿透(良好胶接口下的)橡胶的探头,然后利用缺陷闸门检测回波的波幅。良好 的胶接口会令信号衰减。在脱胶的地方由于声波没法穿透空气,会有较高幅度的回波反射。
Challenge: Initial tests with a 5MHz tranducer showed that we did not penetrate the rubber since a known disbond was not resolved. Therefore a lower frequency 2.25MHz was used with a composite construction to give better penetration and an improved signal to noise ratio. A dual-element was also required because of the curvature of the pipe; a single element was too sensitive to rocking of the transducer. 分析:起初我们使用5MHz的探头,由于声波没法穿透橡胶,因此工件上已知的脱胶部位无法显示出来。 因此我们使用频率第一点的2.25MHz探头,能穿透橡胶和改进了信噪比。另外由于管道有弧度,所以 需要使用双晶探头。因为单晶探头无法消除盲区。
Figure 1. C-scan of pipe. Initial results using 5MHz dual-element. Variable shows % flaw gate height. 图1 C-扫描管道。初步结果使用5MHz的双晶探头。不能明确显示已知脱胶位置。
Figure 2. C scan of pipe using 2.25MHz transducer. Variable shows % flaw gate height. 图2 使用2.25MHz的探头。可明显看到回波幅度较大位置代表脱胶位置。
Conclusion: Pipes and vessels with bonded internal liners can be inspected for disbonds automatically using the Raptor and RCA-10 or RCA-18 and a low frequency composite dual-element transducer. 结论:使用Raptor,RCA-10或者RCA-18扫查器和低频双晶探头,可自动检测管道 和容器与其内衬的脱胶。
相关资讯推荐