Identify the toe crack from the given figure.

Explanation:

Welding defects:

• Cracks
• Cavities
• Solid inclusions
• Incomplete fusion
• Imperfect shape or unacceptable contour

Welding cracks:

Fracture-type interruptions either in the weld or in base metal adjacent to the weld.

Serious defect because it is a discontinuity in the metal that significantly reduces strength.

Caused by embrittlement or low ductility of weld and/or base metal combined with high restraint during contraction.

In general, this defect must be repaired.

Cavities:

Two defect types, similar to defects found in castings:

1. Porosity - Small voids in weld metal formed by gases entrapped during solidification. Caused by the inclusion of atmospheric gases, sulfur in the weld metal, or surface contaminants.

2. Shrinkage voids - Cavities formed by shrinkage during solidification.

Solid inclusion:

Nonmetallic material is entrapped in the weld metal. A most common form is slag inclusions generated during AW processes that use flux. Instead of floating on top of the weld pool, globules of slag become encased during solidification.

Incomplete fusion:

A weld bead in which fusion has not occurred throughout the entire cross-section of the joint.