www.novika.ca
Production of High-Quality
Welds Using Hybrid
Laser/GMAW on Thick Steel
Lorraine Blais, ing., Manager
Mathieu Foster, M. Sc., Scientist
Patrick Martel, ing., Project Manager Laser Processing Department – Novika Solutions
Photonics for Shipbuilding Workshop
Halifax, November 2012
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Agenda
• Novika Solutions
• The Hybrid Laser/GMAW Process
• Test Objectives
• Test Setup
• Results : Weld Quality and Properties
• Conclusions
• Questions & Answers
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Novika at a Glance • R&D/technology transfer center located in La
Pocatière, Québec
• Founded in 1983 under the name “CSTPQ”
• Not-for-profit private organization
• 50 employees, mainly engineers, scientists and
technicians
• Over 1500 projects realized for more than 300
industrial customers
• ISO 9001:2008 certified
=
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• 3 654 m2 building
• Specialized laboratories :
– Laser processing
– Mechanical design
– Mechanical fabrication
– Electronic design
– EMC
– High power electronics
Facilities
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Laser Lab
15 kW and 2 kW fibre laser sources
Three laser safe enclosures equipped with
6-axis robots
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Hybrid Laser-Arc Welding
• laser beam + electric arc from GMAW
HLAW
GMAW
torch
Laser beam
Arc
Keyhole
Protective
gas
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Autogenous laser weld
½’’ thick steel
Laser Only
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• To fill the gaps between the parts
• To control the geometry of the top of the weld
• To reduce cooling speed
Why Add a GMAW Torch?
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One of the first applications of HLAW in Europe
• Meyer Wertft – Germany
• Aker Yard – Finland
• Blohm & Voss – Germany
• Fincantieri – Italy
• …
HLAW in Naval Industry
Me
ye
r W
ert
ft , G
erm
an
y
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Motivations
• Reduction of distortions :
- Savings in straightening from 0,45 $US to
13,72 $US per square foot1
• High welding speed + single pass welding
• Weight reduction
1. Kelly and al, AWS Journal, March 2009
HLAW in Naval Industry
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Seam Tracking Camera
Adaptive Platform
Real-time Adaptation of Parameters
HLAW – Adaptive Process
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Comparison between manual GMAW and HLAW welded
T-joints on ¼’’ thick steel
• 6 minutes vs 8 seconds – including part preparation and
interpass cleaning
• Superior mechanical properties of HLAW
Previous Work
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Previous Work
Excellent fatigue properties due to
- well controlled weld geometry
- limited heat input
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Setup for HLAW
Laser Welding Head
GMAW Torch
Camera
Seam Tracker
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Equipment
• 15 kW IPG Photonics fiber laser
– Fiber optic delivery, very high power available
• Precitec YW50 head
– Focal lens f = 300mm
– Collimating lens fc = 125mm
• Fiber optic cable Φc = 400mm
• Servo-Robot seam tracker
• Lincoln PowerWave 655
welder
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Parts Preparation
As-cut parts – no machining of the edges
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2012 Tests - Objectives
• Caracterize HLAW welds
– On ½’’ thick HSLA A656 gr. 80 steel
– In butt joint configuration
• Compare key characteristics of HLAW with GMAW
– Microstructure
– Microhardness
– Tensile strength
– Bending strength
– Consummables
– Welding time
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Preparation and Welding for ½’’ Steel
GMAW Weld HLAW Weld • 1 welding pass • Chamfer
• 3 welding passes
• Back gouging
• 3 welding passes
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Welding Parameters for ½’’ Steel
• GMAW
– Current: 300A, pulsed mode
– Wire feed speed: 4,7 m/min
– Welding speed: ~0,4m/min
• HLAW
– Laser power: 10 kW
– Current: 135A, pulsed mode
– Wire feed speed: 4,4m/min
– Welding speed: 0,75m/min
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Video, HLAW
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Welds - Surface
Top
Root
GMAW HLAW
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Welds - Macrographs
GMAW HLAW
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Results – Tensile Strength
GMAW HLAW
UTS (ksi) 88 86
YS (ksi) 76 73
Elong % 29 28
Test method : ASTM E8/E8M-11
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Results – Bending Strength
GMAW HLAW
Pass Pass
Test method : AWS D1.1:2010 sect. 4.9.3.1
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Results - Microhardness
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Results – Microhardness
200
210
220
230
240
250
260
-1,0 0,3 0,91,5
5,0
Vic
ke
rs H
ard
ne
ss
Position (mm)
HLAW
200
210
220
230
240
250
260
-1,0 0,3 0,9 1,55,0
Vic
ke
rs H
ard
ne
ss
Position (mm)
GMAW
260-265 250-260 240-250 230-240
220-230 210-220 200-210
Test Method : ASTM E384-10e2
Center of weld = -1,0
Fusion line = 0,0
Top
Root
Top
Root
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Results - Consumables
Wire GMAW HLAW
kg/m lb/ft kg/m lb/ft
0,57 0,37 0,05 0,03
Per length of weld
Gas GMAW HLAW
l/m ft3/ft l/m ft3/ft
248 2,6 31 0,3
Consumables : wire and gas
HLAW = 1/10 GMAW
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Results – Welding Time
GMAW HLAW
minutes minutes
15,0 1,3
per meter of weld
Welding time
HLAW < 1/10 GMAW
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Use of HLAW welding provides:
• Very good weld properties
• Drastic decrease in consumable
consumption, welding time and
preparation, compared to GMAW
Conclusions
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Conclusions
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1,0
GMAW
HLAW
Gas Wire Welding
time
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Questions?
Novika thanks its partners in the
development of laser processes
