Elevator drum cutting and welding in the underground and two, the drum of the split method of winding hoist drum shell, subject to pulsating cyclic load, the fatigue strength requirements are high. Over the years, the reel in operation often occurs cracking and short cracks

当焊丝伸出长度过大时,焊丝会发生过热而成段成段的熔断,致使焊接过程不稳定,飞溅增大,焊缝成形不良,气体对熔池的保护也被减弱。 如果是二保焊连弧焊打底焊时