Is welding undercut a welding appearance defect? How to prevent the occurrence of undercut.
Release time:
2022-09-16
【Summary Description】 Undercut refers to the depression or groove formed in the base metal part along the weld toe. It is the gap left by the arc melting the base metal at the edge of the weld without sufficient replenishment of the deposited metal. The main reason for the generation of undercut is that the arc heat is too high, that is, the current is too large and the speed of the strip is too small. Incorrect angle between electrode and workpiece, unreasonable swing, too long arc, unreasonable welding sequence, etc. will cause undercut. The magnetic deflection of the arc during DC welding is also a cause of undercut. Some welding positions (vertical, horizontal, upturned) will aggravate undercut. The undercut reduces the effective cross-sectional area of the base metal, reduces the carrying capacity of the structure, and also causes stress concentration, which develops into a crack source. Prevention of undercut: correcting the operating posture, selecting reasonable specifications, and adopting good transportation methods will help eliminate undercut. When welding fillet welds, AC welding instead of DC welding can also effectively prevent undercut.
Undercut refers to the depression or groove formed in the base metal part along the weld toe. It is the gap left by the arc melting the base metal at the edge of the weld without sufficient replenishment of the deposited metal.
The main reason for the generation of undercut is that the arc heat is too high, that is, the current is too large and the speed of the strip is too small. Incorrect angle between electrode and workpiece, unreasonable swing, too long arc, unreasonable welding sequence, etc. will cause undercut. The magnetic deflection of the arc during DC welding is also a cause of undercut. Some welding positions (vertical, horizontal, upturned) will aggravate undercut. The undercut reduces the effective cross-sectional area of the base metal, reduces the carrying capacity of the structure, and also causes stress concentration, which develops into a crack source.
Prevention of undercut: correcting the operating posture, selecting reasonable specifications, and adopting good transportation methods will help eliminate undercut. When welding fillet welds, AC welding instead of DC welding can also effectively prevent undercut.
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