weld radio graphs

8/3/2019 Weld Radio Graphs

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LACK OF PENETRATION

Incomplete 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 isa wide, linear indication.


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BURN THROUGH

Burn through (icicles)results when too muchheat causes excessive

weld metal to penetratethe weld zone. Lumps of

metal sag through theweld creating a thick

globular condition on the

back of the weld. On a radiograph, burn

through appears as darkspots surrounded bylight globular areas.


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CLUSTER POROSITY

Cluster porosity iscaused when flux coatedelectrodes are

contaminated withmoisture. The moistureturns into gases whenheated and becomestrapped in the weld

during the weldingprocess. Cluster porosityappear just like regularporosity in theradiograph but the

indications will be


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LONGITUDINAL AND

TRANSVERSE CRACKS

Cracking can be detected in a radiograph only

the crack is propagating in a direction that

produced a change in thickness that is parallel

to the x-ray beam.

Cracks will appear as jagged and often very

faint irregular lines. Cracks can sometimesappearing as "tails" on inclusions or porosity.


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EXCESS REINFORCEMENT

Excess weld reinforcement is an area of a weld,

which has weld metal added in excess of that

specified by engineering drawings and codes. The appearance on a radiograph is a localized,

lighter area in the weld.

A visual inspection will easily determine if the

weld reinforcement is in excess of that

specified


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LACK OF FUSION

Incomplete fusion is lack of complete fusion of

some portions of the metal in a weld joint with

adjacent metal; either base or previouslydeposited 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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INTERNAL UNDERCUT

Internal or root undercut is an erosion of the

base metal next to the root of the weld.

In the radiographic image it appears as a dark

irregular line offset from the centerline of the

weldments.

Undercutting is not as straight edged as LOP

because it does not follow a ground edge.


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EXTERNAL 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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INADEQUATE

REINFORCEMENT Inadequate weld reinforcement is an area of a

weld where the thickness of weld metal

deposited is less than the thickness of the basematerial.

The image density in the area of suspected

inadequacy will be more (darker) than the

image density of the surrounding base material.


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OXIDE INCLUSIONS

Oxide inclusions are usually visible on the

surface of material being welded (especially

aluminum).

Oxide inclusions are less dense than the

surrounding materials and, therefore, appear

as dark irregularly shaped discontinuities in

the radiograph.


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INTERPASS COLD LAP

Cold lap is a condition where the weld filler

metal does not properly fuse with the base

metal or the previous weld pass material(Interpass cold lap).

The arc does not melt the base metal

sufficiently and causes the slightly molten

puddle to flow into base material without

bonding.


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OFFSET or MISMATCH

Offset or mismatch are terms associated with acondition where two pieces being weldedtogether are not properly aligned.

The radiographic image is a noticeabledifference in density between the two pieces.

The difference in density is caused by the

difference in material thickness. The dark, straight line is caused by failure of

the weld metal to fuse with the land area.


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POROSITY

Porosity is the result ofgas entrapment in thesolidifying metal. Porosity

can take many shapes on aradiograph but oftenappears as dark round orirregular spots or specksappearing singularly, in

clusters or rows.Sometimes porosity iselongated and may havethe appearance of having atail, called as Worm-hole

porosity.


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Cluster Porosity


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SLAG INCLUSION

Slag is nonmetallic solid material entrappedin weld metal or between weld material and

base metal.

Radiographically, slag may appear in various

shapes, from long narrow indications to short

wide indications, and in various densities,from gray to very dark.


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ALLIGNED INCLUSIONS


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SUCK BACK

Internal concavity or suck back is condition

where the weld metal has contracted as it cools

and has been drawn up into the root of theweld.

On a radiograph it looks similar to lack of

penetration but the line has irregular edges and

it is often quite wide in the center of the weld

image.


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TUNGSTEN INCLUSION

Tungsten is a brittle and inherently densematerial used in the electrode in tungsten inert

gas welding.

If improper welding procedures are used,tungsten may be entrapped in the weld.

Radiographically, tungsten is more dense than

aluminum or steel; therefore, it shows as alighter area with a distinct outline on the

radiograph.


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