   
|
|
Simply what the name implies! Testing without destroying the part or material. Inspectors
evaluate parts and materials for internal or external defects that could result
in failure. Listed below are some of the industries that utilize Nondestructive
Testing.
-
Automotive
-
Aircraft
-
Amusement parks, roller coaster and other rides
-
Aerospace (NASA)
- Bridge and building construction and maintenance
-
Oil refining and pipelines
-
Railroad tracks and rolling stock
-
Steel mills and casting houses producing the raw stock for industry
Magnetic Particle Inspection
By magnetizing
a ferromagnetic material, areas of cracks or other disruptions of the continuity
at or near the surface of the material will produce a leakage of the magnetic field.
If fine iron particles are applied to the part, these areas of leakage will attract
and hold the iron particles producing an indication on the surface of the part.
Learn more about
Magnetic Particle inspection.
Radiography
Is the study
of the interaction of x and gamma rays with industrial materials. X-rays and gamma
rays are much like light waves, difference being x and gamma rays are extremely
short wave length. Consequently they penetrate materials easily. A film is placed
beneath the object and an image is captured on the film. The radiographer then processes
(develops) the film and produces an image of the part and any defects it may contain.
To view radiographs visit
Iowa State University.
Ultrasonic Inspection
Is much like
radiography except high frequency sound waves are passed through the material. No
image capturing media is used. When the sound meets a void or a material with a
dissimilar acoustic property all or a portion of the sound will be reflected revealing
the void or foreign material in the part. With ultrasound defects can be located
and defined within part, or part thickness can be determined. Visit Iowa State University
for more information on
ultrasonic inspection.
Liquid Penetrant
is considered one of the more simple inspection methods. The part is immersed in
a Penetrant (much like WD40 with a dye added). The penetrant pulls the dye into
any defects open to the surface. After removing the excess penetrant, a developer,
similar to talcum powder, is applied. This helps draw the penetrant to the surface
of the part and provides a contrasting background for the penetrant. Penetrant dyes
come in either a visible red dye or a fluorescent dye. Visit to see
penetrant materials entering
a defect.
By generating
high frequency alternating electrical current through a coil, the associated expanding
and collapsing magnetic fields will produce, in a conductive material, a weak electrical
current and its associated magnetic fields. If the electrical currents are disrupted
by a crack, change in material properties, or nonconductive coating, an indication
will be produced on a meter or Cathode Ray Tube. Eddy current inspections are performed
on aircraft to locate cracks or to determine paint coating thickness. Eddy current
inspections also are used in electrical generating plants to locate thinning and
cracks in tubing. Visit the
Center for Nondestructive Evaluation.
|
|