Welding techniques are numerous and each of them has its peculiarities. Laser beam welding (LBW) uses a laser to concentrate heat, very quickly producing deep, narrow welds. Laser welding is common in nuclear applications and highvolume applications such as automotive component manufacturing, as well as others where speed and excellent accuracy are necessary. Find out more at www.eddyfi.com

1. Inspecting Laser Welds in
Component Manufacturing
Application Note

2. The Challenge
Laser beam welding
(LBW) uses:
• Laser to concentrate heat, very
quickly producing deep, narrow
welds.
Laser welding is common in:
• Nuclear applications
• High-volume applications such as:
• Automotive component manufacturing
• Other applications where speed and excellent accuracy are necessary
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3. The Challenge
Disadvantages of LBW:
• Porosity. Result from instability during partial-penetration, high-power LBW
• Occurs when gas shielding LBW is inadequate (improper flow rate)
• Occurs on aluminum because hydrogen pockets can develop in the
weld metal
• Travel speed. If laser travels too slowly, risk weld puncture—tiny through-
holes affect welded structure integrity. Typical diameter 0.25 mm (0.01 in)
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4. The Challenge
Disadvantages of LBW:
• High cooling rate. Produces solidification cracking (especially in high-
carbon steel). Cracks appear in various locations and orientations—most
commonly longitudinal, subsurface, and surface breaking.
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5. The Challenge
Inspecting laser welds with eddy current testing (ECT) pencil
probes is:
• Very operator dependant
• Slow
• Varying quality
Inspecting laser welds with radiographic testing (RT) is:
• Time consuming (requires specialized personnel/equipment)
• Health and safety issue
Inspecting laser welds with ultrasonic testing (UT):
• Requires couplant
• Is virtually blind to shallow surface-breaking defects
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6. The Challenge
LBW sometimes:
• Involves simultaneously inspecting numerous welds
• Generates an impressive amount of data—need help identify potential
problems
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7. The Solution
Eddy current array (ECA) technology enhances ECT
capabilities by:
• Using several coils in one probe in cooperative sequence to prevent mutual
interference
• Providing wide, complete scan of surface under test
• Designing coils with necessary impedance and penetration to accurately
inspect target material
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8. The Solution
ECA probe designed for this application:
• Hugs surface under test
• Two coils positioned on each weld to detect flaws at roots—current application
required 20 (never done before)
• Integrated encoder:
• Decreases influence of speed on
inspection.
• Makes defect positioning
easier
• Enables using more advanced
filters on recorded inspection data
than possible with other inspection technologies
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9. The Solution
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This type of application is mainly concerned with
identifying and positioning defects.
• Magnifi® (acquisition and analysis software), displays scan data as
easy-to-read C-scans
• Displays clear indications of defects
• Probe encoder supplies spatial positioning information
Probe designed to scan several parallel welds
• C-scans displayed side-by-side in Magnifi

10. The Solution
10 © Eddyfi NDT Inc. 2009–2016
Magnifi integrates assisted analysis automatically
marking defects
• Prevents
analysts
from having
to sift
through
data looking
for defects.

11. The Benefits
Solution offers several benefits over ECT, RT, and UT:
• Shaped to specific laser-weld profiles
• Rapid, stable, simultaneous scan of multiple welds
• Easy to handle — no need for expensive robotic solutions
• On-the-fly assisted analysis
• Easier analysis with C-scan imaging
• Fully computerized data recording and archiving capabilities
11 © Eddyfi NDT Inc. 2009–2016

12. www.eddyfi.com