Fundamental Study on Weld Formation Phenomena of High Speed Lap Seam Welding (7th Report)

Problem for Improving Welding Speed and theirs Countermeasures

Abstract

Problems arising with speed up of seam welding and their countermeasures are discussed. These are summarized as follows.
(1) The upper limit of welding speed is restricted by decrease of ΔIa/Iav. This limit can be raised by arranging preheating electrodes in front of welding electrodes.
(2) The upper limit of welding speed for air tight welding is restricted by discontinuity of joint for plate thickness less than 0.8 mm.
(3) As welding speed increases molten metal comes to solidify where electrode does not be applied resulting in occrence of internal defects. These internal defects can be prevented by arranging forging rollers at the back of welding electrodes.