Basic Studies for the Automatic Fabrication of Welded Built-up Beams

Abstract

In the fabrication of welded built-up beams, longitudinal deformation occurs due to welding. As it prevents improvement of productivity and quality, heating for straightening the welding deformation is necessary. Therefore, control of the deformation due to welding and heating is the base for the automatic fabrication of built-up beams. In this study, techniques to control the deformation are developed. Based on the simple formulas for estimation of the deformation proposed in the previous study, a procedure to calculate the required reverse curvatures to straighten the welding deformation is presented and a method to simulate the fabrication procedure is developed. From the simulation of the fabrication procedure it is concluded that, in heating for straightening, deep-heated depth is more economical than wide-heated breadth in yielding the same curvature. To apply the results obtained to automatic fabrication, welding and heating parameters such as welding current, voltage and speed, and heated depth and breadth are selected and fabrication cost is expressed by the parameters, which are optimized under the constraints. According to the optimized results, the higher welding current reduces the fabrication cost. Results obtained through executing the simulation method described herein can be used in the guidance of welding and heating procedures instead of depending on the experience of skilled workers--and this can contribute to an increase in productivity and quality.