Download 2 X SAW

The Major Constraint
• Standard over the road:
– 4.1 m high by 2.6 m wide
– Net weight 21 tons
• Very expensive
– > 4.83 m high
• Rail
– 3.4 m, and heights are limited to 4.0 m.
Available Materials
Welding
2
Global Wind Tower
Solutions
Typical Wind Tower Plant
Sand Blast
Fittings & QA
(2 X MIG)
100% UT
Internals
Counter weight
(1 X MIG)
Aluminum
Paint
Doorway
Welding
Or
(2 X SAW)
(2 X FCAW)
Plate Storage
&
Quality
Cutting
Courtesy: Lincoln Electric
Circumferential Welding
Plate Rolling and Tacking
(1 X MIG)
Flange to Can
Ring to Can
Can to Can
(2 X SAW)
Longitudinal Welding
(1 X SAW)
Boxes With a Red Border Indicate Processes Involving
Welding
FACILITY AUTOMATION CONSIDERATIONS
•
•
Establish Requirements, Develop Concepts, and Model Concepts.
Ensure that the Process Flow and Facility expectations can be achieved with the equipment specified..
Wind Tower Welding Productivity Seminar
Tower Manufacturing
www.davi.com
http://www.directindustry.com/prod/davi-promau/sheet-metal-calendering-line-forwind-tower-16273-367798.html
Weldment
• Weldment has three distinct zones
– fusion zone
• area of weldment that melted and resolidified
• contains base and filler metal
– HAZ
• area of weldment that did not melt, but properties
has changed due to the heat input
• contains base metal
– base metal
• area of weldment that was unaffected by weld
• contains base metal (obviously)
Welding
7
From Lincoln Electric
Welding
8
HAZ
• Dependent on:
–
–
–
–
type of alloy
heat added
initial heat
cooling rate
Welding
Kalpakijan & Schmid: Manufacturing
9
Engineering and Technology”
GMAW (MIG)
• Continuous solid wire electrode
• shielding from outside source of gas
– Ar, He, CO2, or most likely a mixture
• weld metal also contains deoxidizers
– improves weld quality
• lends itself well to robotics
Welding
10
Groover: “Fundamentals of Modern
Manufacturing”
Welding
11
FCAW (Flux Core)
• Continuous tubular electrode
• Shielding from:
– solid flux in the middle
– external shielding gas
• Advantages over GMAW:
– 4 to 8 X deposition rate out of position
– 1.5 X deposition rate in position
• especially for weldments greater than .5”
– alloy opportunities by changing flux
Figure from Lincoln Electric
Welding
12
SSFCAW (Self Shielded Flux Core)
• Continuous tubular electrode
• Shielding from solid flux in the middle
• Advantages over GMAW:
– outdoor applications
– alloy opportunities by changing flux
Welding
13
SAW (Submerged Arc)
• Continuous solid wire electrode
• granular flux:
– shielding
– prevents spatter and sparks
– insulation to allow deeper penetration
• flat or horizontal position, circular
• good quality, toughness, uniform properties
• usually automated
Welding
14
Welding
Figure from Groover
15
Welding
16
Cary: Modern Welding Technology
Residual Stress
• caused by contraction of metal during
solidification and cooling
• control or minimize by:
–
–
–
–
–
–
fixtures
procedures (order of welds)
parameters (speed, filler metal . .
preheat
stress relief
proper design
Welding
17
Figure from Lincoln Electric
Figure from Lincoln Electric
Global Wind Tower
Solutions
Entry Door Frame Welding
• Can be welded with a variety of processes, but
most commonly SAW or FCAW.
• FCAW equipment recommendation:
– CV400/LN-7 Pro
• FCAW consumable recommendation:
– UltraCore® E71T-12
• Handheld SAW is preferred, but flux selection is
critical due to metallurgical requirements, and flux
feedability concerns.
• Handheld equipment recommendation:
– LN-9 Undercarriage with Flux Feeding System,
combined with Idealarc® DC-600 or DC-655
• Handheld consumable recommendation
– Lincolnweld® L-61 with 860, 960, or WTX™ Flux
Slide from Lincoln Electric
Global Wind Tower
Solutions
Cost Reduction Savings
Potential In Summary
AFTER
50º
6mm
36m
m
36mm Plate
•
•
•
•
•
•
•
Change Joint Configuration
Decrease Joint Angle
Increase Joint Land
Improve Weld Procedure
Use AC to Increase Deposition
Eliminate Back Gouging
Improved Energy Efficiency with
Power Wave® Technology
Slide from Lincoln Electric
Global Wind Tower
Solutions
Longitudinal & Circumferential
Welding Review
• Typically Tandem, triple Tandem or Twin Tandem
systems, utilizing 2, 3 or 4 wires
and welding
heads.
• With 2 or 3 wire Tandem Arc these welds can be
accomplished single pass per side up to 36 mm.
• Multi-pass welds are used when there is poor fit-up,
greater plate thickness and to improve weld
toughness.
• With 3 wires, single pass thickness of up to
40 mm
may be achieved.
• The Included Angle used on Bevels for Tandem Arc can
be greatly decreased to 50o maximizing productivity
and enabling single pass per side welding.
• Lincoln Electric Power Wave® AC/DC 1000® power
sources are ideal in these applications, with proven
productivity and quality increases, as well as the
opportunity for significant cost reduction.
Slide from Lincoln Electric
Global Wind Tower
Solutions
Customer Success
BEFORE
70º
36mm
2mm
AFTER
50º
6mm
36mm
• Transferring technologies developed for the pipeline
industry, in 2002 Lincoln Electric developed a new
procedure for Apoyos Metalicos
• The new procedure replaced a 9-pass single arc
approach with a 2-pass tandem arc procedure
• Switched from CV to CC
• Consumable recommendation for impacts at
o
®
™
20 C; Lincolnweld P230, P223, or WTX flux with
Lincolnweld® L-61 wire
• Consumable recommendation for impacts at
40oC; Lincolnweld® WTX™ flux with Lincolnweld® L-61
wire
• Cost Savings – greater than 50% reduction in weld
time and consumable savings
13mm Plate
19mm Plate
Slide from Lincoln Electric
36mm Plate
INTEGRATED SYSTEMS STRATEGY
It is important to note that an effective automation “strategy”
seamlessly ties together all of the necessary components
- Controls
- Fixturing
- Power Supplies
- Sensing
- Process Monitoring
- Networking
- User Interface
to consistently provide the desired cost and quality benefits.
Each component needs to be considered to ensure it is not the
weak link of the overall completely integrated system.
Wind Tower Welding Productivity Seminar
Slide from Lincoln Electric
What is Important to Consider when Evaluating Automation
- Experience • Supplier experience in Welding Automation
Controls, as well as systems integration specifically
for your application, will significantly help to ensure
requirements are met and mistakes are not repeated.
Process-Power Supplies-Sensors-Motion-etc.
Unless your application is very unique, try
not to be the guinea pig
Wind Tower Welding Productivity Seminar
Slide from Lincoln Electric
Improving Subarc welding productivity
• Productivity depends on:
– Deposition rate
– Set up time / operator skill
– Fit up and edge prep
– Steel quality / property requirements
– Other bottlenecks
– Defect Costs
• Severity
• Occurrence
• Detection
26
SAW Deposition Rates
Single Electrode DC+
Diameter
Current
2.4mm
3.2mm
4.0mm
4.8mm
600 Amps
800 Amps
900 Amps
1200 Amps
10 to 12 kg/hr is the baseline
27
Deposition
Rate
8 Kg/hr
10 Kg/hr
12 Kg/hr
17 Kg/hr
SAW Deposition Rates
Twin Arc
Diameter
Current
2 x 1.6mm
2 x 2.0mm
2 x 2.4mm
980 Amps
1300 Amps
1400 Amps
Deposition Rate
17Kg
18Kg
19Kg
50% increase in deposition rate versus single wire DC+
• Power source must be capable and stable at high currents
• Loss in penetration (return to back gouging…)
• Good when fit up / joint preparation is not perfect
• Can be used in tandem with single wire or another twin
28
SAW Deposition Rates
Multiple Arcs
Number
of Arcs
1
Configuration
DC+
Deposition
rate
12 Kg/hr
2
DC+/AC
22 Kg/hr
3
DC+/AC/AC
32 Kg/hr
4
DC+/AC/AC/AC
52 Kg/hr
5
DC+/AC/AC/AC/AC
63 Kg/hr
Huge increases in deposition rate versus single wire DC+
High penetration allows modified joint design
One pass per side decreases set up time
29
Flux/wire consumption
Weld volume
V-butt joint
Thickness
12 mm
14 mm
16 mm
18 mm
20 mm
22 mm
30
X-butt joint
bevel angle:60º
Bevel angle: 60º
root face: 6 mm
root face: 6 mm
Volume
0.41 Kg/m
0.60 Kg/m
0.79 Kg/m
1.03Kg/m
1.45 Kg/m
1.76 Kg/m
Thickness
12 mm
14 mm
16 mm
18 mm
20 mm
22 mm
Volume
0.19 Kg/m
0.29 Kg/m
0.41 Kg/m
0.61 Kg/m
0.70 Kg/m
0.87 Kg/m
Example of a 4-wire SAW Procedure
•
•
•
•
Lead arc:
Second arc:
Third arc:
Fourth arc:
DC+ 1000 amps, 32 volts
AC
900 amps, 35 volts
AC
800 amps, 38 volts
AC
725 amps, 41 volts
• All wires are 4.0 mm diameter
• All heat inputs are essentially the same
32
4 Wire SAW Example: Lead Arc
• In most cases the lead arc is DC+
• The low voltage focuses the arc current (resulting in
deep penetration). Can provide up to 80% of the total
penetration.
33
4 Wire SAW Example: Arc 2
• The second arc increases penetration because
of the proximity to the first arc.
• Lower current, higher voltage produces a wider,
shallower bead profile.
34
4 Wire SAW Example: Arc 3
• Current lower than Arc 2; voltage higher.
• This layer adds to the width of the bead. It should
bring the weld metal approximately to the surface.
35
4 Wire SAW Example: Arc 4
• Usually characterized by the lowest current and
highest voltage.
• Shapes the cap of the weld. Angle of electrode,
voltage, current and flux type determine toe
angles, cap height, shape.
36
Finished Weld
• The sketch shows the
complete weld bead
(with a tack weld).
• The heat input of each
arc was very similar,
but different shapes
were created by
manipulation of volts,
amps, spacings and
angles.
37
The Major Constraint
• Standard over the road:
– 4.1 m high by 2.6 m wide
– Net weight 21 tons
• Very expensive
– > 4.83 m high
• Rail
– 3.4 m, and heights are limited to 4.0 m.
Modular Bolted
Cast Weld
Falk Lüddecke, Werner Rücker, Marc
Seidel, Jens Assheuer:
Tragverhalten von
Stahlgussbauteilen in OffshoreWindenergie-Anlagen unter
vorwiegend ruhender
und nicht ruhender Beanspruchung