Discontinuities-Welding

In joint- base material

Name/Type Location Appearance Cause Indication Appearance
Visual: image or your sketch Key Description of appearance MPI LPI
Within plate or pipe, cavity/void or only exposed Only esposed
worked product in inclusion elongated edge edge
direction of working, and flattened during detection detection
subsurface planar rolling/forming possible. possible.
planar, flat, thin unfused direction Linear particle Linear
Lamination concentration bleedout
area/separation

V shapped cutout on the weld it may come from drill Notches Notches act as
holes, grooves or cross- enhance collection
sectional variations.
Notches result in uneven defect points,
the toe of a weld stress distribution, leading detection by highlighting
beyond the limits of to stress peaks – known concentrating surface
Notches as the notch effect magnetic flux. defects with
fusion for fillet and
groove welds penetrant.

Discontinuities
Welding related- welded joint
Name/Type Location Appearance Cause Indication Appearance
Visual image/sketch Key Description of appearance MPI LPI
Over-deposition of will not show will not show
weld material

Excessive
Convexity Welded joint Excessively raised or rounded weld be
 Discontinuities-Welding

Over-deposition of will not show will not show

weld material

Excessive Excessive weld metal beyond specified

Reinforcement Welded joint limits

Insufficient weld will not show will not show

material or excessive
cooling

Excessive Excessive inward depression in weld

Concavity Welded joint bead

Insufficient weld will not show will not show

material or
inadequate fusion

Incomplete fill of the weld groove or

Underfill Welded joint joint
 Discontinuities-Welding

UT Radiography
high Darker region then
amplitude adjacent through
signal solid through section
reflector using
normal beam

Notches aid in Notches provide

probe reference features
sensitivity for image quality
calibration assessment and
and serve as defect measurement.
reference
points for
defect
analysis.

UT Radiography
There will be There will be a colour
amplitude change on the film
change in the where the excessive
region of the convexity
excessive
convexity
 Discontinuities-Welding

There will be There will be a colour

amplitude change on the film
change in the where the excessive
region of the Reinforcement
excessive
Reinforcemen
t

There will be There will be a colour

amplitude change on the film
change in the where the excessive
region of the concavity
excessive
concavity

There will be There will be a colour

amplitude change on the film
change in the where the underfill is
region of the located
underfill
 Discontinuities- Castings
Casting

Name/Type Location Appearance Cause Indication Appearance

Visual image/sketch Key Description of appearance MPI
Shrinkage Cavity Within casting Rounded or irregular voids Rapid cooling during Cannot be seen as most
solidification, cavities are withing the
inadequate feeding casting and if at all close
system to the surface there will
be indications but high
chance its going to be
vague

Porosity Throughout casting Small voids or bubbles Trapped gases Magnetic particle spots if
during solidification, at the surface will be
improper mold filling circular in shape

Inclusions Within casting Foreign material or particles Contaminants in the If at the surface the
molten metal, magnetic particle will
improper filtering take the shape of the
inclusion and its magnetic
field if linear, if circular
then it will not show up.
 Discontinuities- Castings
Cold Shut At casting surface Mismatched or incomplete surface Insufficient molten Linear marks where the
metal flow or interface line has
turbulence during occurred
casting

Misrun At casting surface Incomplete casting of the part Premature cannot perform MPI
solidification,
inadequate filling of
the mold
 Discontinuities- Castings

LPI UT Radiography
Will appear if the Will show the cavity pulse Will show
cavities are closer to on the display of the UT darker spots on
the surface and have instrument and based on the the flim.
opening for the signal strength and the time
penetrant to enter. the depth is found

If at the surface will Will show the porosity pulse Will show
show up as round on the display of the UT darker spots on
spots instrument. the flim.

Only surface inclusion high amplitude signal Will show

can be seen and will reflected frrom the inclusion darker spots on
take the shape of the shows up on the instrument the flim
inclusion or based on compared to
the inclusion surface other areas.
charecteristics
 Discontinuities- Castings
if the interface line is high amplitude signal Will show
showing upon the reflector using normal beam darker spots on
surface then LPI the flim
indication will be compared to
linear other areas.

cannot perform LPI high amplitude signal Will show

reflector using normal beam difference in
colour in the
region where
misrun has
occurred
 Discontinuities- Forming and Forging

Forging
Indication
Name/Type Location Appearance Cause
Appearance
Key Description of
Visual image/sketch MPI LPI
appearance

Linear as the
Linear lapping
indications if the causes a
Incomplete material
Overlapping of lapping that linear cavilty
Forging Lap On the surface bonding or
material layers occurred did not when folded
inadequate heating
create a circular to the
shape adjacent
metal

Linear Linear
Inadequate material indications at indications at
Cold Shut On the surface Surface irregularities
flow or poor bonding the cold shut the cold shut
interface interface

Linear Indication
Excessive strain or Linear
that are like
Forging Crack Within material Visible crack or fissure inadequate Indication if at
lightening strikes
temperature control the surface
if at the surface

cannot perform cannot

MPI perform LPI
Foreign material or Contaminants in the
Forging
Within material impurities within the material or poor
Inclusions
structure material preparation
Discontinuities- Forming and Forging
 Discontinuities- Forming and Forging

UT Radiography

Immersion UT
is possible
and will show
will show colour
amplitude
change at the
change at the
lap section
lap section
then other
regions

will indicate
change in will show colour
amplitude change at the
when running cold shut region
the scan

will indicate
will show colour
change in
change as the
amplitude
shape of the
when running
crack
the scan

will indicate
will show colour
change in
change as the
amplitude
shape of the
when running
inclusion
the scan
Discontinuities- Forming and Forging
 Discontinuities- Heat Treat, finishing

Finishing
Name/Type Location Appearance Cause Indication Appearance
Key Description of
Visual image/sketch appearance MPI LPI UT
On the surface Visible linear Abrasive contact,
scratches or marks improper handling

Surface Scratches

Corrosion, abrasive
wear, or impurities
Small, shallow in the finishing
Surface Pitting On the surface depressions or holes process

Bubbles or raised Improper coating

Coating Blisters On coated surface areas in the coating application or curing

Improper paint
application or
Runs or drips in the excessive paint
Paint Drips On painted surface paint thickness
 Discontinuities- Heat Treat, finishing

Radiography
 Discontinuities- InService

In-Service
Indication
Name/Type Location Appearance Cause Appearance
Key Description of
Visual image/sketch appearance MPI LPI UT Radiography
On the surface or Visible rust, pitting, or Exposure to
within material material degradation moisture, chemicals,
or environmental
factors
Corrosion

Mechanical stress,
fatigue, or
Visible cracks or environmental
Cracking Within material fissures factors

Wear and On the surface or Surface abrasion, loss Friction, abrasive

Erosion material loss of material, or pitting contact, or erosion
Damaged seals,
Visible fluid or gas gaskets, or
Leaks At joints or seams leakage connection points
Overloading, stress,
Structural Visible warping, or environmental
Deformation In structure bending, or distortion factors