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DEFECTS OBSERVED IN RADIOGRAPHIC TESTING

Radiographic defects

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Page 1: Radiographic defects

DEFECTS OBSERVED IN RADIOGRAPHIC TESTING

Page 2: Radiographic defects

What is Radiographic Testing

• It is the non-destructive testing to observe the various defects in the weld joints.

• It is most common in Piping fabrication workshops.

• 100% weld joints in High pressure vessels/pipes are radio-graphed.

Page 3: Radiographic defects

How radiograph testing is done in case of piping spools.

• The welded joint is placed before the undeveloped film.• The source emits x-rays or gamma rays which penetrates

through the welded part.• The bead formed by weld pool is having different density as

compared to the parent material and hence it allows less or more rays to pass through it.Finally we get imprints on the film.

• For a perfect joint , Joint efficiency factor should be more then 1.

• We are assigning particular film for certain marked welded joint to re-weld in case of defect.

Page 4: Radiographic defects

The following discontinuities are typical of all types of welding.

• Cold lap due to improper fusion of filler wire with base metal.

Page 5: Radiographic defects

Porosity is the result of gas entrapment in the solidifying metal.

Page 6: Radiographic defects

Cluster porosity is caused when flux coated electrodes are contaminated with moisture.

Page 7: Radiographic defects

Slag inclusions are nonmetallic solid material entrapped in weld metal or between weld and base metal.

Page 8: Radiographic defects

Incomplete penetration (IP) or lack of penetration (LOP) occurs when the weld metal fails to penetrate the joint.

Page 9: Radiographic defects

Incomplete fusion is a condition where the weld filler metal does not properly fuse with the base metal.

Page 10: Radiographic defects

Internal concavity or suck back is a condition where the weld metal has contracted as it cools and has been drawn up into the

root of the weld.

Page 11: Radiographic defects

Internal or root undercut is an erosion of the base metal next to the root of the weld.

Page 12: Radiographic defects

External or crown undercut is an erosion of the base metal next to the crown of the weld.

Page 13: Radiographic defects

Offset or mismatch are terms associated with a condition where two pieces being welded

together are not properly aligned.

Page 14: Radiographic defects

Inadequate weld reinforcement is an area of a weld where the thickness of weld metal deposited is less

than the thickness of the base material.

Page 15: Radiographic defects

Excess weld reinforcement is an area of a weld that has weld metal added in excess of that specified by

engineering drawings and codes.

Page 16: Radiographic defects

Cracks can be detected in a radiograph only when they are propagating in a direction that produces a change in

thickness that is parallel to the x-ray beam.

Page 17: Radiographic defects

Discontinuities in TIG welds • Tungsten inclusions. Tungsten is a brittle and inherently dense material used in the

electrode in tungsten inert gas welding.

Page 18: Radiographic defects

Oxide inclusions are usually visible on the surface of material being welded (especially aluminum

Page 19: Radiographic defects

Burn-Through results when too much heat causes excessive weld metal to penetrate the weld zone.

Page 20: Radiographic defects

Thanking you……