Basuc Weld Faults And Their Causes Flashcards Preview

Shield Metal Arc Welding 1 > Basuc Weld Faults And Their Causes > Flashcards

Flashcards in Basuc Weld Faults And Their Causes Deck (4)
Loading flashcards...
1

All weld defects

Undercut
Incomplete penetration
Underfill
Incomplete fusion
Porosity
Slag inclusion
Cracking

2

Types of cracking

Hot cracks, cold cracks

External cracks- crater, longitudinal and transverse

Internal cracks- underbead cracking

3

Types of distortion

Longitudinal- shrinks along the length and bows inwards

Transverse- tendency for the plates in a butt joint to pull together down the length of the joint.

Methods to prevent: tacks along the length or put a wedge 12in to 18in ahead of the welding to hold the plates apart or prespacing.

Angular- the face shrinks and pulls the two pieces together
Method to fix: on a tee joint weld the other side of the joint.

4

Distortion controls

•Avoid over welding
•Deposit the greatest amount of weld in the shortest amount of time (high rate of travel and use largest electrode possible)
•back-step welding sequence
•internment welding sequence
•Pre-bending or pre-spacing
•preheating and post-heating