Effect of Weld Quality for Welding Current in Steel Construction

• Main Authors: Wang,Ta-Ming, 王大明
• Other Authors: 趙鳴 博士
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/97989545990754896193

碩士 === 正修科技大學 === 營建工程研究所 === 102 === This study mainly explored on the effect of different deposited current on weld contour quality and test results in a welding steel works construction site. To meet the demands of the number of constructions, the welding worker in the construction site often increase the current and accelerate the welding speed to increase the amount of the deposited weld. Therefore, this study simulated the construction site and divide the test pieces into T-shaped welding of fillet welding and butt welding of complete penetration welding through hand-welded method. According to standard procedure, making normal welding test pieces and using different current from 270 A to 350 A, 18 test welding pieces with increased current were made. The test pieces underwent non destructive testing such as visual test, magnetic particle test and ultra-sonic test and destructive testing such as stretching, bending and macroscopic testing to compare the difference with the results to provide a basis for welding construction and quality inspection. The test results obtained by this study showed that the magnetic particle test and ultra-sonic test of non destructive testing can't effectively determine whether there are weld defects. Moreover, the bending test of destructive testing proved that the test welding pieces met the specification requirements. The compression test results of T-shaped welding showed that only two fillet weld did not meet the specifications. The values in the stretching test of destructive testing showed that increasing the current fusion of weld contour caused embrittlement and poor fusion in the weld itself and the fusion of the base metal. The tests also confirmed that when the welding current is increased to 310 A-330 A, the base metal and wire in the fusion shows defects during destructive testing. If the welding current is maintained between 270 A-300 A and the base metal and wire is completely in fusion, the test pieces will pass the test and meet the quality requirements of the construction. Therefore, weld contour fusion and changing welding currents would cause different degrees of defects in the weld quality. Effectively setting the current and voltage stability of welding can reduce potential defects. Keywords: Welding、Non Destructive Testing、Destructive Testing