Table 1.

The quality defects of ship group products.

Type of defect	Quality characteristic	Qualitative factors
Assembly defects	Deformation	(1) Positioning method; (2) assembly sequence; (3) welding parameters
	Size deviation	(1) Assembly margin; (2) assembly compensation amount; (3) positioning method
Surface welding defects	Porosity	(1) Welding current; (2) welding speed; (3) welding voltage; (4) the groove is not clean
	Slag inclusion	(1) Slag not cleaned; (2) groove form; (3) welding current; (4) welding speed
	Incomplete penetration	(1) Welding current
	Incomplete fusion	(1) Groove type; (2) assembly clearance; (3) wire feeding speed; (4) welding current; (5) electrode diameter
	Bite edge	(1) Welding current
	Welding tumor	(1) Welding voltage; (2) welding current; (3) wire feeding speed; (4) welding speed
	Welding pit	(1) Welding speed; (2) welding current; (3) welding voltage
Internal welding defects	Wormhole	(1) Welding speed; (2) welding current; (3) welding voltage; (4) welding material; (5) base metal thickness
	Lack of penetration
	Kissing bonds
	Hooking bonds
	Cracks