Weld defects, causes, and remedies

SMAW(Shielded Metal Arc Welding

1. Weld Carbon Steel Plates in 1G Position using SMAW Weld Defects, Causes, and Remedies

2. Objective: At the end of the lesson, you are expected to; Identify the different weld defects its causes and remedies.

3. A weld should have a good appearance. However, a defective weld is one that will be strong enough to do the job and may fail after it is put into used. Weld defects usually happen when the correct preparation and/or welding techniques are not used. Weld Defects

4. General Classification of Weld Defects: 1. Structural Defects – include surface and internal cracks and defects Types of Structural Defects: 1.1 Crater Cracks – cracks left at the depression at the end of the bead. Cause: Improper termination of the electrode at the end of the weld  

5. 1.2 Longitudinal Cracks – cracks run parallel to the weld bead. They may be in the bead itself or in the metal along the edge of the bead. Causes: a . Wrong electrode b . Improper joint design c . Poor edge preparation d . Poor clamping of the welded joint General Classification of Weld Defects:

6. 1.3 Cross-sectional Crack – cracks across the weld bead. Causes: a. Wrong electrode b . Improper joint design c . Poor edge preparation d . Poor clamping of the welded joint General Classification of Weld Defects:

7. 1.4 Undercutting – depression at the toe of the weld – the weld metal is below the level of the base metal. Causes: Faulty electrode manipulation b . Current too high c . Travel speed is too slow General Classification of Weld Defects:

8. 1.5 Slag Inclusion – entrapment of nonmetallic materials such as cellulose or limestone at the weld and base metal. Causes: a. Poor edge preparation b . Dirty filler metal and Parent metal c . Incorrect use of the different welding techniques General Classification of Weld Defects:

9. 1.6 Porosity – small gas pockets or holes in the welded metal Causes: Dirty filler metal and parent metal b . Too short arc length c . Insufficient paddling time General Classification of Weld Defects:

10. 1.7 Poor Penetration – happens when the joint or root weld penetration does not meet the weld requirement for full strength Causes: a. Poor edge preparation b . Travel speed is too fast c . Low current setting General Classification of Weld Defects:

11. General Classification of Weld Defects: 1.8 Incomplete Fusion – when the filler metal and parent metal are not completely fused Causes: a. Poor edge preparation b . Travel speed is too fast c . Low current setting

12. GOOD LUCK!!!