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http://dx.doi.org/10.5762/KAIS.2018.19.10.121

A Study on the Development of Diagnosing System of Defects on Surface of Inner Overlay Welding of Long Pipes using Liquid Penetrant Test  

Lho, Tae-Jung (School of Mechatronics Engineering, Tongmyong University)
Publication Information
Journal of the Korea Academia-Industrial cooperation Society / v.19, no.10, 2018 , pp. 121-127 More about this Journal
Abstract
A system for diagnosing surface defects of long and large pipe inner overlay welds, 1m in diameter and 6m in length, was developed using a Liquid Penetrant Test (PT). First, CATIA was used to model all major units and PT machines in 3-dimensions. They were used for structural strength analysis and strain analysis, and to check the motion interference phenomenon of each unit to produce two-dimensional production drawings. Structural strength analysis and deformation analysis using the ANSYS results in a maximum equivalent stress of 44.901 MPa, which is less than the yield tensile strength of SS400 (200 MPa), a material of the PT Machine. An examination of the performance of the developed equipment revealed a maximum travel speed of 7.2 m/min., maximum rotational speed of 9 rpm, repeatable position accuracy of 1.2 mm, and inspection speed of $1.65m^2/min$. The results of the automatic PT-inspection system developed to check for surface defects, such as cracks, porosity, and undercut, were in accordance with the method of ASME SEC. V&VIII. In addition, the results of corrosion testing of the overlay weld layer in accordance with the ferric chloride fitting test by the method of ASME G48-11 indicated that the weight loss was $0.3g/m^2$, and met the specifications. Furthermore, the chemical composition of the overlay welds was analyzed according to the method described in ASTM A375-14, and all components met the specifications.
Keywords
Automatic PT inspection system; Deformation analysis; Diagnosing surface defects; Liquid Penetrant Test(PT); Overlay welding; Structural strength analysis; 3D modeling;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
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