Surface Discontinuities for Welds
The following images have been provided courtesy of Agfa Gevaert Pty Ltd. These reproductions of radiographs show various weld defects as they might appear in a radiograph.
Excessive penetration (SXP)
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.Radiograph of Excessive Penetration (Courtesy Agfa NDT)
(click radiograph to enlarge)
Root concavity (SRC)
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.Radiograph of Internal (Root) Concavity (Courtesy Agfa NDT)
(click radiograph to enlarge)
Incompletely filled groove (SGI)
A continuous or intermittent channel at the top surface of the weld and running along the length of the weld. It may be at the centre of the weld, where it is sometimes known as external concavity or insufficient fill, or may be at the edges of the weld where it is known as incompletely filled groove.Radiograph of External Concavity (Courtesy Agfa NDT)
(click radiograph to enlarge)
Incompletely Filled Groove
Undercut (SUC)
An irregular groove at the top edge (toe) of a weld caused by contraction of the weld metal, or by burning away (gouging) of the parent metal. Appears as a dark irregular band along the top edge of the weld metal.Radiograph of External Undercut (Courtesy Agfa NDT)
(click radiograph to enlarge)
Undercut can also occur at the root of the weld, although this can easily be confused with lack of root fusion.Radiograph of Internal Undercut (Courtesy Agfa NDT)
(click radiograph to enlarge)
Linear misalignment (HiLo)
A planar misalignment of the two sides being welded. May appear as light and dark sides.Radiograph of Linear Misaligment (Courtesy Agfa NDT)
(click radiograph to enlarge)
Linear misalignment may have a linear indication associated with it caused by the protruding edge of one of the plates. This has the appearance of a lack of penetration indication.Radiograph of Lack of Penetration (Courtesy Agfa NDT)
(click radiograph to enlarge)
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Internal Discontinuities for Welds
The following images have been provided courtesy of Agfa Gevaert Pty Ltd. These reproductions of radiographs show various weld defects as they might appear in a radiograph.
Longitudinal Crack (KL)
Cracks appear a fine dark lines, mostly jagged edges, sometimes discontinuous. Its detection is dependent on its orientation relative to the radiation beam.Radiograph of Longitudinal Crack (Courtesy Agfa NDT)
(click radiograph to enlarge)
Longitudinal root crack (KL)
This form of crack occurs mostly in the parent metal adjacent to the root run of the weld. It appears as a fine dark line, mostly jagged edges, sometimes discontinuous. Its detection is dependent on its orientation relative to the radiation beam.Radiograph of Longitudinal Root Crack (Courtesy Agfa NDT)
(click radiograph to enlarge)
Transverse Crack (KT)
A transverse crack runs across the weld bead and sometimes into the parent metal. It appears as a fine dark line, mostly jagged edges, sometimes discontinuous. Its detection is dependent on its orientation relative to the radiation beam.Radiograph of Transverse Crack (Courtesy Agfa NDT)
(click radiograph to enlarge)
Lack of side fusion (LS)
A lack of union between the weld metal and the parent metal at the side of a weld. Its image appears as a straight dark line or band, depending on the orientation of the beam of radiation. Its detection depends on its orientation relative to the beam orientation, and sometimes requires an additional exposure with the beam aligned parallel to the weld preparation face.Radiograph of Lack of Side Wall Fusion Crack (Courtesy Agfa NDT)
(click radiograph to enlarge)
Lack of inter-run fusion (LI)
A lack of union between adjacent weld runs in a multi-run weld. It appears as a faint dark line with sharply defined edges.Radiograph of Lack of Inter-run Fusion (Courtesy Agfa NDT)
(click radiograph to enlarge)
Lack of root fusion (LR)
A lack of union of the weld metal with the parent metal at the root of a weld. Appears as a straight line or band at one or both edges of the weld root image.Lack of Root Fusion
Incomplete root penetration (LP)
Failure of the weld metal to extend into the root area of a joint. Appears as a dark continuous or intermittent band with mostly straight edges. In close square butt joints it may appear as a continuous or broken line. There is often a line of fine porosity associated with this defect.Radiograph of Incomplete Root Penetration (Courtesy Agfa NDT)
(click radiograph to enlarge)
Inclusion (IN)
Slag or other foreign matter trapped between weld runds or between the weld and the parent metal. Appears as mostly irregular shapes.Radiograph of Inclusion (Courtesy Agfa NDT)
(click radiograph to enlarge)
Linear inclusion (IL)
Also known as a slag line. Caused by lines of slag trapped, generally between the weld metal and parent metal, in a multi-run weld. Appears as one or more dark bands, mostly with irregular edges, running along a weld.Radiograph of Linear Inclusion (Courtesy Agfa NDT)
(click radiograph to enlarge)
Tungsten inclusion (IT)
An inclusion of tungsten from a tungsten electrode used in the gas tungsten arc (GTAW) process. Appears as small white sharp edged images in the weld metal due to the fact that tungsten is much denser than steel or aluminium.Radiograph of Tungsten Inclusion (Courtesy Agfa NDT)
(click radiograph to enlarge)
Gas pore (GP)
A mostly spherical gas hole in the weld metal. Appears as one or more circular dark images.Radiograph of Scattered Porosity (Courtesy Agfa NDT)
(click radiograph to enlarge)
Linear porosity (PL)
A line of mostly small round images aligned along a weld. Note that this can sometimes indicate a lack of fusion defect which may not be immediately obvious.Radiograph of Root Pass Aligned Porosity (Courtesy Agfa NDT)
(click radiograph to enlarge)
Localised porosity (PG)
A group of gas pores confined to a small area of a weld. Appears as a cluster of small round indications. These discontinuities are sometimes elongated, where they are referred to as “worm holes”.Radiograph of Cluster Porosity (Courtesy Agfa NDT)
(click radiograph to enlarge)
Burn through (BT)
A localised collapse of the weld pool leaving a hole in the bottom of the weld run. Appears as an irregularly shaped globular dark area.Radiograph of Burn Through (Courtesy Agfa NDT)
(click radiograph to enlarge)
The following images have been provided courtesy of Agfa Gevaert Pty Ltd. These reproductions of radiographs show various weld defects as they might appear in a radiograph.
Excessive penetration (SXP)
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.Radiograph of Excessive Penetration (Courtesy Agfa NDT)
(click radiograph to enlarge)
Root concavity (SRC)
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.Radiograph of Internal (Root) Concavity (Courtesy Agfa NDT)
(click radiograph to enlarge)
Incompletely filled groove (SGI)
A continuous or intermittent channel at the top surface of the weld and running along the length of the weld. It may be at the centre of the weld, where it is sometimes known as external concavity or insufficient fill, or may be at the edges of the weld where it is known as incompletely filled groove.Radiograph of External Concavity (Courtesy Agfa NDT)
(click radiograph to enlarge)
Incompletely Filled Groove
Undercut (SUC)
An irregular groove at the top edge (toe) of a weld caused by contraction of the weld metal, or by burning away (gouging) of the parent metal. Appears as a dark irregular band along the top edge of the weld metal.Radiograph of External Undercut (Courtesy Agfa NDT)
(click radiograph to enlarge)
Undercut can also occur at the root of the weld, although this can easily be confused with lack of root fusion.Radiograph of Internal Undercut (Courtesy Agfa NDT)
(click radiograph to enlarge)
Linear misalignment (HiLo)
A planar misalignment of the two sides being welded. May appear as light and dark sides.Radiograph of Linear Misaligment (Courtesy Agfa NDT)
(click radiograph to enlarge)
Linear misalignment may have a linear indication associated with it caused by the protruding edge of one of the plates. This has the appearance of a lack of penetration indication.Radiograph of Lack of Penetration (Courtesy Agfa NDT)
(click radiograph to enlarge)
Back To Top
Internal Discontinuities for Welds
The following images have been provided courtesy of Agfa Gevaert Pty Ltd. These reproductions of radiographs show various weld defects as they might appear in a radiograph.
Longitudinal Crack (KL)
Cracks appear a fine dark lines, mostly jagged edges, sometimes discontinuous. Its detection is dependent on its orientation relative to the radiation beam.Radiograph of Longitudinal Crack (Courtesy Agfa NDT)
(click radiograph to enlarge)
Longitudinal root crack (KL)
This form of crack occurs mostly in the parent metal adjacent to the root run of the weld. It appears as a fine dark line, mostly jagged edges, sometimes discontinuous. Its detection is dependent on its orientation relative to the radiation beam.Radiograph of Longitudinal Root Crack (Courtesy Agfa NDT)
(click radiograph to enlarge)
Transverse Crack (KT)
A transverse crack runs across the weld bead and sometimes into the parent metal. It appears as a fine dark line, mostly jagged edges, sometimes discontinuous. Its detection is dependent on its orientation relative to the radiation beam.Radiograph of Transverse Crack (Courtesy Agfa NDT)
(click radiograph to enlarge)
Lack of side fusion (LS)
A lack of union between the weld metal and the parent metal at the side of a weld. Its image appears as a straight dark line or band, depending on the orientation of the beam of radiation. Its detection depends on its orientation relative to the beam orientation, and sometimes requires an additional exposure with the beam aligned parallel to the weld preparation face.Radiograph of Lack of Side Wall Fusion Crack (Courtesy Agfa NDT)
(click radiograph to enlarge)
Lack of inter-run fusion (LI)
A lack of union between adjacent weld runs in a multi-run weld. It appears as a faint dark line with sharply defined edges.Radiograph of Lack of Inter-run Fusion (Courtesy Agfa NDT)
(click radiograph to enlarge)
Lack of root fusion (LR)
A lack of union of the weld metal with the parent metal at the root of a weld. Appears as a straight line or band at one or both edges of the weld root image.Lack of Root Fusion
Incomplete root penetration (LP)
Failure of the weld metal to extend into the root area of a joint. Appears as a dark continuous or intermittent band with mostly straight edges. In close square butt joints it may appear as a continuous or broken line. There is often a line of fine porosity associated with this defect.Radiograph of Incomplete Root Penetration (Courtesy Agfa NDT)
(click radiograph to enlarge)
Inclusion (IN)
Slag or other foreign matter trapped between weld runds or between the weld and the parent metal. Appears as mostly irregular shapes.Radiograph of Inclusion (Courtesy Agfa NDT)
(click radiograph to enlarge)
Linear inclusion (IL)
Also known as a slag line. Caused by lines of slag trapped, generally between the weld metal and parent metal, in a multi-run weld. Appears as one or more dark bands, mostly with irregular edges, running along a weld.Radiograph of Linear Inclusion (Courtesy Agfa NDT)
(click radiograph to enlarge)
Tungsten inclusion (IT)
An inclusion of tungsten from a tungsten electrode used in the gas tungsten arc (GTAW) process. Appears as small white sharp edged images in the weld metal due to the fact that tungsten is much denser than steel or aluminium.Radiograph of Tungsten Inclusion (Courtesy Agfa NDT)
(click radiograph to enlarge)
Gas pore (GP)
A mostly spherical gas hole in the weld metal. Appears as one or more circular dark images.Radiograph of Scattered Porosity (Courtesy Agfa NDT)
(click radiograph to enlarge)
Linear porosity (PL)
A line of mostly small round images aligned along a weld. Note that this can sometimes indicate a lack of fusion defect which may not be immediately obvious.Radiograph of Root Pass Aligned Porosity (Courtesy Agfa NDT)
(click radiograph to enlarge)
Localised porosity (PG)
A group of gas pores confined to a small area of a weld. Appears as a cluster of small round indications. These discontinuities are sometimes elongated, where they are referred to as “worm holes”.Radiograph of Cluster Porosity (Courtesy Agfa NDT)
(click radiograph to enlarge)
Burn through (BT)
A localised collapse of the weld pool leaving a hole in the bottom of the weld run. Appears as an irregularly shaped globular dark area.Radiograph of Burn Through (Courtesy Agfa NDT)
(click radiograph to enlarge)