-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
1/29
Alternat ives to RadiographicWeld Inspection
October 2007
Puget Sound Naval Shipyard & IMF
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
2/29
Radiographic Testing
Definition:
Radiography is a method fornondestructive inspection ofcomponents and assemblies that is
based on differential absorption ofpenetrating radiation by the partbeing inspected.
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
3/29
Radiography
Top view of developed film
X-ray film
The part is placed between the
radiation source and a piece of film.
The part will stop some of theradiation. Thicker and more dense
sections stop more of the radiation.
= more exposure
= less exposure
The film darkness(density) will vary with
the amount of radiation
reaching the filmthrough the test object.
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
4/29
Radiographic Images
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
5/29
Radiographic Testing
Advantages:
a) Volumetric inspection. Magnetic Particle and Liquid Penetrant are forsurface inspections even when applied to eachlayer.
b) Can be used on a variety ofmaterials.
c) Film provides a permanent record.
d) Gamma radiography does notrequire electrical power.
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
6/29
Radiographic Testing PSNS Applications:
a) Piping Welds. b) Structural Welds.
c) Castings. d) Various components for internal
structure (info).
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
7/29
Radiographic Testing
Detectable Flaws:
a) Slag. b) Porosity.
c) Cracks. d) Inclusions.
e) ID Root Conditions (contour
and oxidation)
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
8/29
Structural
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
9/29
Piping
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
10/29
Slag
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
11/29
Porosity
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
12/29
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
13/29
Casting Cracks and Inclusions
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
14/29
Butt Weld RTPipe Size and Material
Pipe sizes (IPS)
Range - in to 20 Inches Material
Carbon Steel 2-1/2 to 16 inches CuNi (70:30 & 90:10) Mostly 2 to
5 inch
NiCu (Monel) Mostly 2 to 5 inch
Grade 300 Series CRES - 4 inch and
less Inconnel 4 inch and less
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
15/29
Field Radiography
In the field and
shipboard, structures
are radiographed using
radioactive sources
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
16/29
Radiography Challenges
Limitations:
Safety considerations lead to: Large, expensive crews needed to guardRT areas.
Limited (1 or 2) joints inspected per shift.
Disruption of other work.
Potential safety hazard.
Certain types of flaws are difficult
to detect. Film interpretation requires skill.
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
17/29
Radiography Challenges
Further Limitations:
Crew size is approximately 15people; can be as many as 30 onaircraft carriers.
Training personnel: 80 hours initialtraining; 24 hours of trainingannually to maintain proficiency.
Cost/Schedule impact on projects.
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
18/29
Radiography Challenges
Global Pacific Operations
Designing/installing shielding toreduce crew size is costly.
Exposure devices are shielded with
depleted uranium; some foreigncountries do not allow the exposuredevices on their soil.
Shipping expenses involved withperforming RT in other countries.
Access to spaces by foreign
nationals.
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
19/29
Radiography Challenges
Could crew sizes be smaller?
Could exposure devices be shieldedwith a different material?
Could X-ray machines be more
portable to facilitate performing x-rayshipboard? (i.e., source-film distance
difficult to maintain with shipboardinterferences, weight of machine ~400lbs.)
What digital equipment is available?
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
20/29
Ultrasonic Testing
Definition:
Ultrasonic inspection introducesbeams of high frequency soundinto the piece. The sound reflected
at material interfaces is analyzed todefine the presence and location ofdiscontinuities.
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
21/29
High frequency sound waves are introduced into a material andthey are reflected back from surfaces or flaws.
Reflected sound energy is displayed versus time, and theinspector can visualize a cross section of the specimen showingthe depth of features that reflect sound.
f
Oscilloscope, or flaw
detector screen
plate
crack
0 2 4 6 8 10
initialpulse
crack
echo
back surfaceecho
Ultrasonic Inspection
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
22/29
Ultrasonic Testing
Uses:
Detect internal flaws Bonding of materials
Measure material thickness.
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
23/29
Ultrasonic Testing
Advantages.
Deep penetration, for thickmaterials.
Detects extremely small flaws.
Only one surface needs to beaccessible.
Volumetric scanning Portable.
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
24/29
UT
PSNS Applications: Thickness gauging.
Pipe/tank liquid level. Silver Braze joint bond. Welds for discontinuities.
Detectable Flaws: Cracks.Voids. Porosity. Laminations.
Unbond in materials. Thickness variations.
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
25/29
Ultrasonic Testing
Limitations:
Requires experienced technicians. Rough, irregular or thin parts are
difficult to test.
Surface flaws may not bedetectable.
Requires direct coupling. Reference standards are required.
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
26/29
Ultrasonic Inspection
Angle beam ultrasonic
flaw detection is used
to inspect welds using
the shear wave mode
of transmission to
detect welding
discontinuities such as
lack of fusion and slag
inclusions.
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
27/29
Ultrasonic Challenges
A-scan must be recordable.
Samples with known defects arerequired to prove new processes. Root convexity, oxidation, porosity.
Surface/ID detection ofdiscontinuities.
False positives (too sensitive). Joint configuration (fittings, elbows,
wall thicknesses).
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
28/29
Ultrasonic Specifications
Military Specifications 1688,
1689, 2035A, TP-278 are similarto ASME, API, and ABS.
Current acceptance criteria is forstructural welds not piping welds.
-
8/4/2019 1100 Gorman RT-UT Presentation for CTMS Oct 07
29/29
Points of Contact
Engineering Ole Hovland
360.476.7418 Dennis Yeats
360.476.8744
Radiography (RT)
Primary - Richard Franklin360.476.2990
Secondary - Christina Klinkert360.476.3321
Ultrasonic (UT) Primary - William Robbins
360.476.2990 Secondary - Nona Brown
360.476.3321