Development for Automatic Welding System with Reduction of Residual Stress. - Effect of Vibrations with Different Frequencies
Development of automatic welding system is an important problem for automatic manufacturing system. It is well known that residual stress is measured near the bead because base metal is heated near the bead. Tensile residual stress on the surface degrades fatigue strength. In this paper, the effect of vibrations with different frequencies on reduction of residual stress is examined. Firstly, two thin plates are butt-welded using ultrasonic vibrations with different frequencies on each plate. When thin plates are welded using ultrasonic vibrations with different frequencies, tensile residual stresses are reduced and reduction rate is largest compared with other conditions. Secondly, two thin plates are butt-welded using ultrasonic vibration and vibration with low frequency. In this case, tensile residual stresses are reduced and reduction rate is largest compared with other conditions. Thirdly, a welding of automobile wheel for automatic welding system is performed using ultrasonic vibration. As a result, it is confirmed that the reduction of residual stress is reduced. Lastly, reduction of tensile residual stress is demonstrated using an analytical model based on elasto-plastic characteristic. Ill. 6, bibl. 2 (in English; summaries in English, Russian and Lithuanian).
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