Inspection of the Crossed Areas of Welds Joining Hull Sections by Time-of-Flight Diffraction Technique
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摘要: 利用超声衍射时差(TOFD)技术检测船舶大合拢焊缝交叉部位时，为了覆盖由于焊缝余高带来的扫查盲区，设计了与焊缝成45°夹角的两次斜向扫查的专用TOFD检测工艺，并推导了计算缺陷长度和深度的公式，以修正斜向扫查带来的缺陷长度和深度值误差。使用该工艺和计算公式在现场检测了18万吨散货船大合拢焊缝交叉部位共46处，与X射线照相结果相比，设计的TOFD检测方法能够基本满足检测要求。Abstract: A special TOFD inspection procedure has been designed to cover the blind testing zone due to the weld reinforcement height when testing the crossed areas of longitudinal and transverse welds joining hull sections. It uses TOFD probe pairs scanning along two 45°angled paths towards the welds direction. In order to eliminate measurement error brought by angled scanning, several formulae have been derived to compute the corrected values for defects length and depth. Using the designed procedure, 46 crossed areas have been inspected successfully on the 180 kiloton cargo vessel. After comparing the TOFD results to radiographic testing, the TOFD inspection procedure validation has been demonstrated, which could satisfy the requirement of testing crossed areas of welds.
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Keywords:
- Welds of joining hull sections /
- Crossed areas /
- TOFD
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