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The quality of bean-column joint is related to ensure the whole building’s stress transfer in steel structure. The welded joints will produce residual stress, blow hole , slag inclusion, hot cracking and cold cracking problems. This is caused from the fusion and solidification between welding metal and base metal when the bean-column joint of skeleton adopts welded joint s in steel structure.
This research focuses on abnormal fusion of welding work in construction site. The welder tends to speed-up the welding fusion by increasing the arc current or welding foreign matter in order to increase the fusion. This paper simulates the abnormal fusion in each practical situation, such as base metal, groove type and selection of fusion foreign matters, and then adopts the standard operation process to examine test pieces by manual welding. The 15 test pieces are divided into normal fusion and increase arc current fusions. We examine them with six destructive tests includes, Nondestructive Ultrasonic Test and Tensile Test, Slide Bend Test, Impact Test, Chemical test, Metallog raphic Test and Micro-specimen Test. At the end, we record test numbers, taking macro- and micro-observation diagram to compare the normal and abnormal weldings.
The research results demonstrate that all test results are in compliance with the regulations, except three normal fusion test pieces. However, there is at least one examined item not in compliance with the regulation in the eleven abnormal fusion tested pieces. The balance of the only one two-electrode tested piece meets the regulation requirements. The test figures in impact tests show the best fusion zone’s embrittement with base metal among other examining items. The tests also prove that the nondestructive UT Test cannot determine if the there is an abnormal fusion under the condition of foreign matter and electrode fuse. Thus, it is an important issue for the supervisors to effectively manage the abnormal fusion in construction sites.
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