Cause of Cracking on Weld Seam of Electric Bicycle Frame

Some electric bicycles produced by a company cracked soon after they were used. The causes of cracking of frame were analyzed by macroscopic observation and metallographic examination. The results show that the cracking of electric bicycle frame was caused by the lack of fusion between the fixed steel plate and the frame steel pipe. The main reason was that the surface of frame steel pipe was seriously rusted and not cleaned before welding.