Wormholes / Crater Pipe

Elongated pores or wormholes Characteristically, wormholes are elongated pores (Fig. 3) which produce a herring bone appearance on the r...

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Porosity - Weld Defects

The characteristic features and principal causes of porosity imperfections are described. Best practice guidelines are given so welders ca...

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Geometric Shape Imperfections

This article looks at those imperfections related to poor geometric shape and will concentrate on the following: Excess weld metal   ...

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Root Concavity - Suck Back

A shallow groove that may occur in the root of a butt weld. Common causes Root concavity is caused by shrinkage of the weld pool in t...

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Excessive Penetration

Excess weld metal protruding through the root of a fusion (butt) weld made from one side only. With pipe welding this type of imperfection ...

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Incompletely Filled Groove - Underfill

This is a continuous, or intermittent, channel in the surface of a weld, running along its length, due to insufficient weld metal. Comm...

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Linear Misalignment (High-Low)

Linear Misalignment also known in the USA as high-low. This imperfection relates to deviations from the correct position/alignment of the j...

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Overlap (Cold Lap)

This is an imperfection at a toe or root of a weld caused by metal flowing on to the surface of the parent metal without fusing to it. It m...

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Geometric Shape Imperfections - Undercut

This is an irregular groove at the toe of a run in the parent metal. The figure shows undercut at surface of a completed joint but it may a...

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Geometric Shape Imperfections - Excess weld metal

Excess weld metal (also called cap height, overfill or reinforcement) Fig.1. Excess weld metal This is weld metal lying outside the p...

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Reheat Crack

The characteristic features and principal causes of reheat cracking are described. General guidelines on best practice are given so that we...

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Lamellar Tearing

Lamellar tearing can occur beneath the weld especially in rolled steel plate which has poor through-thickness ductility. The characteristic...

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Hydrogen Cracks

Hydrogen cracking may also be called cold cracking or delayed cracking. The principal distinguishing feature of this type of crack is that ...

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