Phenomenon: The arc pit is a phenomenon that the welder machine at the end of the weld, which not only weakens the weld strength, but also causes cracks during the cooling process.

Reason: It is mainly because the arc extinguishing time is too short at the end of the welding machinery , or the current used in welding the thin plate is too large.

Control measures: When the weld seam of the welder is finished, make the electrode stay for a short time or do a few round trips. Do not suddenly stop the arc so that there is enough metal to fill the weld pool. When welding, the proper current is ensured, and the main component can be added with a pilot plate to lead the crater out of the weldment.