Welding Flashcards
What is welding?
A manufacturing process where 2 or more metal parts are joined together
Name some weld joint defects and discontinuities.
Misalignment, Undercut, Under fill, Excessive concavity or convexity, incomplete fusion, incomplete or insufficient penetration, spatter, cracks, porosity
Define Misalignment and the cause of it
Amount a joint is out of alignment at the root.
Cause:
Carelessness
Also due to joining different thicknesses
(transition thickness)
Define Undercut, mention the cause, prevention and repair
Definition - A groove cut at the toe of
the weld and left unfilled
Cause - High amperage, electrode
angle, long arc length, rust
Prevention - : Clean metal before
welding
Repair - Weld with smaller electrode,
sometimes must be low hydrogen
with preheat
Define Under fill, mention the cause, prevention and repair.
Definition - The weld surface is below the
adjacent surfaces of the base metal
Cause - Improper welding techniques
Prevention - Apply proper welding techniques
for the weld type and position
Repair - Simply weld to fill – may
require preparation by grinding
Define excessive concavity or convexity, mention cause prevention and repair.
Definition - Concavity or convexity of a fillet weld
which exceeds the specified allowable limits
Cause - Amperage and travel speed
Prevention - Observe proper parameters and
techniques.
Repair - Grind off or weld on – must blend
smoothly into the base metal
Define incomplete fusion, mention the cause, prevention and repair.
Definition - Where weld metal does not form a
cohesive bond with the base metal
Cause - Low amperage, steep electrode angles, fast
travel speed, short arc gap, lack of preheat, electrode
too small, unclean base metal, arc off seam
Prevention - Eliminate the potential causes
Repair - remove and re-weld, being careful to
completely remove the defective area
Incomplete or insufficient penetration, definition, cause, prevention, repair
Definition - When the weld metal does not extend
to the required depth into the joint root
Cause - Low amperage, low preheat, tight root
opening, fast travel speed, short arc length
Prevention - Correct the contributing factor(s)
Repair - remove and re-weld
Define spatter, mention cause, prevention, and repair
Definition - Small particles of weld metal
expelled from the welding operation
which adhere to the base metal surface
Cause - Long arc length, severe electrode
angles, high amperages
Prevention - Correct the cause; base
metal can be protected with coverings
or high temperature paints
Repair - Remove by grinding or sanding
