(1) covered electrode is bad or humid.
(2) The weldment has moisture, oil stain or rust.
(3) The welding speed is too fast.
(4) The current is too strong.
(5) The arc length is not appropriate.
(6) The thickness of weldment is large, and the metal cools too fast.
Carbon dioxide gas shielded welding
(1) The bottom material is not clean.
(2) The welding wire is rusted or the flux is wet.
(3) Poor spot welding and improper welding wire selection.
(4) The dry extension length is too long, and the CO2 gas protection is not detailed.
(5) The wind speed is high and there is no windproof device.
(6) The welding speed is too fast and the cooling is fast.
(7) Spark spatter sticks to the nozzle, causing gas turbulence.
(8) The gas purity is poor and there are many impurities (especially moisture).
Submerged arc welding
(1) There are organic impurities such as rust, oxide film and grease in the weld.
(2) The flux is wet.
(3) The flux is polluted.
(4) The welding speed is too fast.
(5) The flux height is insufficient.
(6) The height of flux is too high, which makes it difficult for gas to escape (especially if the flux particle size is fine).
(7) The welding wire is rusted or stained with oil.
(8) Improper polarity (especially when it is polluted during docking, it will produce pores).