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

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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