kss - welding defect

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POWEREPC INFRASTRUCTURE

SOLAR RESOURCES

Project Review by Director & CEO 04-Jan-12

Lanco Babandh Power Limited

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Defect A flaw or flaws that by nature or

accumulated effect render a part or product unable to meet minimum applicable acceptance standards or specifications. The term designates rejectability.

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Discontinuity An interruption of the typical structure of

a material, such as a lack of homogeneity in its mechanical, metallurgical, or physical characteristics. A discontinuity is not necessarily a defect.

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Babandh Phase – I & II

Common weld defects include:

i. Inclusionsii. Porosityiii. Lack of penetrationiv. Lack of fusionv. Undercut

vi. Cracksvii. Offset or Mismatchviii.Burn Throughix.Excessive Penetrationx.Root concavity

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Babandh Phase – I & II

Inclusions

• Slag

• Tungsten

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Babandh Phase – I & II

Porosity Porosity is a series of rounded gas pockets or voids in the weld

metal, and is generally cylindrical or elliptical in shape.

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Porosity

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Babandh Phase – I & II

Lack of penetration As the name implies, is a lack of weld penetration through the thickness of the joint (or penetration which is less than specified). It is located at

the center of a weld and is a wide, linear indication

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Lack of penetration

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Babandh Phase – I & II

Lack of fusion Lack of complete fusion of some portions of the metal in a weld joint with adjacent metal; either base or previously deposited weld metal. On a radiograph, this appears as a long, sharp linear indication, occurring at the centerline of the weld joint or at the fusion line.

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Lack of fusion

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Babandh Phase – I & II

Undercut Undercut is a groove melted in the base metal at the edge of a weld and left unfilled by weld metal. It represents a stress concentration that often must be corrected, and appears as a dark indication at the toe of a weld.

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Undercut

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Babandh Phase – I & II

Root Undercut Root undercut appears as an intermittent or continuous groove in the internal surface of the base metal, backing ring or strip along the edge of the weld root.

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Babandh Phase – I & II

CRACKS Cracks appear a fine dark lines, mostly jagged edges, sometimes

discontinuous. Its detection is dependent on its orientation relative to the radiation beam.

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Babandh Phase – I & II

Offset or Mismatch A joint is out of alignment at the root

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Burn Through A localized collapse of the weld pool leaving a hole in the bottom of the weld run. Appears as an irregularly shaped globular dark

area.

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Excessive Penetration

Weld metal protruding through the root of the weld. Appears as a light continuous or more often intermittent, irregularly shaped band within

the image of the weld.

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Excessive Penetration

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Root Concavity Sometimes called suck-back. A shallow groove in the root of a butt

weld. Appears as a dark area along the centre of the weld.

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THANKS

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