Kss - Welding Defect

© LANCO Group, All Rights Reserved© LANCO Group, All Rights Reserved

POWEREPC INFRASTRUCTURE

SOLAR RESOURCES

Project Review by Director & CEO 04-Jan-12

Lanco Babandh Power Limited

© LANCO Group, All Rights Reserved

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



Inclusions

• Slag

• Tungsten



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

metal, and is generally cylindrical or elliptical in shape.


Porosity

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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


Lack of penetration

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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.


Lack of fusion

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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.


Undercut

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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.



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

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



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


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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Kss - Welding Defect

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