NON-DESTRUCTIVE
TESTING – METALS Radiography:
Radiographic testing methods may be used to detect discontinuities
in welds for structural steel, petroleum piping, high pressure piping
and pressure vessel welds. It may also be used as an investigative
tool to determine the locations of suspected items in concrete walls,
columns and elevated slabs.
This method uses not only X-ray machines, but also radioactive
isotopes which are much easier to use at remote job sites. This
method will detect cracks, porosity, slag, incomplete fusion, and
incomplete penetration in full penetration welds on pipe, pressure
vessels and structural steel.
Typical applications include welds in bridges, buildings, pipe
lines, piping systems, vessels or tanks.
Applicable codes include:
ANSI/AMSE B31.1; 31.3; 31.5, 31.9 and Section IX
API 650 and 1104
AWS D1.1, and 1.5
AWWA
Various military standards and project specifications
Radiography will detect embedded items, such as conduits, reinforcing
steel, post/pre-tensioned cables and panel boxes which are embedded
in concrete up to two feet thick.
Radiography in generally performed at a time when the immediate
area can be kept clear of all unauthorized personnel. Safety for
radiation levels while exposures are being made is of particular
concern and must be controlled at all times.
Ultrasonic Testing:
Typical applications include full penetration moment connections
in new construction and renovation projects and pipe welds. Ultrasonic
testing is also used to determine wall thickness. Thickness testing
is often used in conjunction with tangent radiography for the purpose
of corrosion analysis.
Ultrasonic testing uses ultra high frequency sound waves to detect
flaws in pipe and structural steel welds by introducing the sound
waves into the parent metal either longitudinally or at an angle.
Typical deficiencies which may be observed are incomplete penetration,
slag pockets, porosity and laminations in ferrous, as well as non-ferrous
material.
Ultrasonic testing provides a practical test method of weld examination
for internal and surface discontinuities. This method may be performed
in the field as easily as in a laboratory or shop environment.
Magnetic Particle Testing:
Magnetic particle testing is used for the detection of surface
or slightly subsurface discontinuities in ferrous material only.
This method is used to detect cracks, laps, seams, inclusions and
other discontinuities on or near the surface of ferromagnetic materials.
Magnetic particle testing may be applied to raw material, billets,
finished and semi-finished materials, welds and in-service parts.
Dye Penetrant Testing:
Dye penetrant testing is used to detect discontinuities in non-ferrous
materials which are open to the surface. Discontinuities may be
cracks, seams, laps, cold shuts, laminations, through leaks and
lack of fusion. This method is applicable to in-process, final and
maintenance examination.
This method may also be effectively used when examining non-porous,
metallic materials, both ferrous and non-ferrous, and of non-metallic
materials, sucha s glazed or fully densified ceramics, plastics
and glass.
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