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Welding of Duplex Stainless steel
Conference Paper · May 2013
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Welding of Duplex Stainless Steel
ELGA meeting 16/5-2013
Hans Åström
DUPLEX STEELS - Index
• Chemical composition
• Microstructure
• Properties
- Mechanical
- Corrosion
• Welding
- Welding procedures and welding methods
- Shielding gases
- Joint preparation
- Set-up and tacking
- Welding techniques
- Repair welding
• Imperfections – how to avoid
• Post weld cleaning
• Utilizing the strength of duplex steels
• Applications
How to weld duplex – 2
1
DUPLEX STEELS - History
First duplex stainless steel was produced end 1920:
Avesta 453 S
(26%Cr, 5%Ni, 1.5%Mo)
Avesta 453 E
(26%Cr, 4%Ni)
Modern duplex steels, 1960- (possible to alloy using nitrogen)
Sandvik 3RE60
(18.5%Cr, 5%Ni, 2.7%Mo)
2304
(23%Cr, 4.5%Ni, 0.10%N)
2205
(22%Cr, 5.5%Ni, 3%Mo, 0.17%N)
SAF
2507®
(25%Cr, 7%Ni, 4%Mo, 0.27%N)
LDX
2101®
(21%Cr, 1,5%Ni, N, Mn)
LDX 2404
(24Cr, 3,6Ni, 1,6Mo, 3Mn, 0,27N)
How to weld duplex – 3
DUPLEX STEELS - Chemical composition
Chemical composition (typical values wt-%)
Grade
ASTM
EN
C (max)
N
Cr
Ni
Mo
Mn
S32101
1.4162
0.02
0.22
21.5
1.5
0.3
5
Filler LDX
-
-
0.03
0.16
23.5
7
<0.5
0.8
2304
S32304
1.4362
0.02
0.10
23
5
<0.3
1.5
Filler 2304
-
-
0.02
0.12
24.5
8
<0.3
0.8
2205
S32205
1.4462
0.02
0.17
22
6
3.1
1.5
Filler 2205
E2209
22 9 3 N L
0.02
0.16
23
9.5
3.2
0.8
SAF 2507®
S32750
1.4410
0.02
0.27
25
7
4
1.5
Filler 2507
E2594
25 9 4 N L
0.03
0.23
25.5
10
4
1.2
LDX
2101®
How to weld duplex – 4
2
DUPLEX STEELS - Microstructure
+
Austenitic
=
Duplex
Ferritic
Duplex steels combine the austenitic and
ferritic properties
How to weld duplex – 5
DUPLEX STEELS - Microstructure
BASE MATERIAL
WELD METAL
Controlled cooling
Cooling rate can vary
 Ferrite 50%
 Ferrite 20-70%
3
DUPLEX STEELS - Ferrite content
The ferrite content is influenced by several factors:
Chemical composition
•
•
Composition of filler
Dilution with parent metal (joint preparation/parameters)
Cooling time (1200800°C)
•
•
•
Heat input
(welding procedure)
Material thickness
(welding procedure)
Interpass temperature (welding procedure)
Use right filler metal and follow the welding procedure
How to weld duplex – 7
DUPLEX STEELS - Ferrite content
The ferrite content for duplex steel is best predicted by...
• WRC-92
…or measured with...
• Ferritescope (Fischer MP-3)
• Manual point counting (ASTM E562)
Big variations between and within methods.
Always use mean values.
How to weld duplex – 8
4
DUPLEX STEELS - Physical properties
Heat conductivity:
Mild steel
47 W/mºC
CrNi steel
15 W/mºC
Duplex steel
14 W/mºC
Thermal expansion:
Mild steel
12 x10-6/ºC
CrNi steel
17 x10-6/ºC
Duplex steel
13 x10-6/ºC
How to weld duplex – 9
DUPLEX STEELS – Position
Hot coil
LDX 2404®
2507
550
LDX 2101®
450
400
Duplex
500
2205
2304
4565
350
4439
300
250
200
Austentic
Yield strength, Rp0.2 [MPa], Min. värden
600
4438
4404
254 SMO
904L
4307
4436
150
Bildplacering
Bildplacering
Corrosion resistance, ASTM G150 CPT
How to weld duplex – 10
5
DUPLEX STEELS – Mechanical properties
Tensile strength - typical values base metal
700
Rp0.2 (MPa)
600
500
400
300
200
100
0
4404
2304
LDX 2101
2205
2507
How to weld duplex – 11
DUPLEX STEELS – Mechanical properties
Impact toughness - typical values base metal
350
300
KV (J)
250
Austenitic
Duplex
Carbon Steel
200
150
100
50
0
-150
-125
-100
-75
-50
-25
0
25
Temp. (°C)
How to weld duplex – 12
6
Welding Duplex Stainless Steels – Properties
DUPLEX STEELS – Corrosion resistance
Duplex steels has generally a very good corrosion resistance that increases
with the contents of Cr, Mo and N.
•
•
•
•
General corrosion
Pitting and crevice corrosion
High resistance to stress corrosion cracking due to high strength
High resistance to inter crystalline corrosion
CPT (°C) ASTM G150
100
80
60
Base metal
40
Weld metal
20
0
4404
LDX 2101 SAF 2304
2205
SAF 2507 254 SMO
How to weld duplex – 13
DUPLEX STEELS – Key to success
Five keys for a successful result
1. Use the right filler metal to achieve right structure = right properties
2. Choose “optimal” welding method for each application
3. Right joint preparation, proper fit-up and clean weld zone
4. Let the welders train how to weld duplex and follow the welding
procedure
5. Chose right and make the post weld cleaning carefully
How to weld duplex – 14
7
DUPLEX STEELS – Shaping
Duplex steels are prone to precipitations when subjected to temperatures
below app. 900°C.
Precipitations lowers both ductility and corrosion resistance.
LDX 2101®
2304
2205
SAF 2507TM
Hot forming (C°)
900-1100
900-1100
950-1150
1025-1200
Solution heat treatment (C°)
1020-1080
950-1050
1020-1100
1040-1120
Stress relieving (C°)
1020-110
950-1050
1020-1100
1040-1120
How to weld duplex – 15
DUPLEX STEELS – PWHT
Duplex steels shall in general not be
PWHT.
Risk of embrittlement due to intermetallic phases in the temperature
range 600-900°C and due to ferrite
decomposition at 350-525°C.
These temperatures should be
avoided.
No risk at normal welding operations.
Reduction of impact strength to 50% compared to solution annealed condition
How to weld duplex – 16
8
DUPLEX STEELS - Properties
CONCLUSIONS
• Duplex steels combines austenitic and ferritic steels properties
•
•
High mechanical properties
High resistance against corrosion
• Welds within the ferrite range 30-70% has good mechanical and
corrosion properties.
• Less expansion and heat conductivity compared to austenitic
steels.
• Higher forces for cold forming compared to austenitic steels.
How to weld duplex – 17
DUPLEX STEELS - Welding
All conventional welding methodes can be applied to DSS
•
•
•
•
•
MMA (SMAW)
FCW (FCAW)
MIG (GMAW)
TIG (GTAW)
SAW
How to weld duplex – 18
9
DUPLEX STEELS - Welding methods MMA
Characteristics
•
Flexibility - all positions
•
Flexibility - chemical composition
•
Flexibility – coating composition
•
Plate thickness – 2 mm and upwards
•
Suitable for:
•
Bildplacering
Fabrication welding
•
On site welding
•
Repair welding
How to weld duplex – 19
DUPLEX STEELS - Welding methods MMA
How to weld duplex – 20
10
DUPLEX STEELS - Welding methods MIG
Characteristics
•
High productivity
•
Plate thickness up to 6 mm
•
Plate thickness below 1,5 mm requires special
Bildplacering
welding machines (CMT or SuperPulse®)
•
Best weldability using pulsed arc but spray and
short arc also possible
•
Good weld metal properties i.e. impact toughness
•
Suitable for:
•
Mechanised welding
•
Robot welding
How to weld duplex – 21
DUPLEX STEELS - Welding methods TIG
Characteristics
•
High quality weld metals
•
Superior weld bead appearance
•
Plate thickness up to 4 mm + root runs
•
All positions
•
“Low” productivity
•
Good weld metal properties i.e.
Bildplacering
impact toughness
•
Suitable for:
•
Single side root runs
•
Pipes and tubes
•
Mechanised welding
How to weld duplex – 22
11
DUPLEX STEELS - Welding methods SAW
Characteristics
•
High productivity
•
Good weld bead appearance
•
Plate thickness 10 mm and upwards
•
Flat position
•
High heat input
•
Suitable for:
•
Bildplacering
Pre fabrication
•
Welding using a agglomerated flux
•
Importance with right wire and flux combination
How to weld duplex – 23
DUPLEX STEELS - Welding methods FCW
Characteristics
•
High productivity
•
Good positional weldability
•
Surface appearance
•
Plate thickness 2,5 mm and upwards
•
Wide parameter box / welder friendly
•
Suitable for:
•
Pre fabrication
•
On site welding
•
Horisontal and position wires
•
Single side welding against ceramic backing
Bildplacering
How to weld duplex – 24
12
DUPLEX STEELS - Welding methods plasma
Characteristics
•
High energy and focused arc
•
High welding speed
•
High quality weld metals with low deformation
•
Good weld metal properties i.e.
•
Good penetration using keyhole
•
Plate thickness up to 8 mm
•
Suitable for:
Bildplacering
impact toughness
•
Automatic and mechanised welding
•
Longitudinal pipe welding
•
Root PAW followed by TIG or SAW
•
Filler wire unless PWHT can be performed
How to weld duplex – 25
DUPLEX STEELS - Welding methods laser
Characteristics
•
High energy, high focus arc
•
High quality weld metals with low deformations
•
Deep penetration
•
YAG or CO2 laser
•
High productivity
•
Good weld metal properties i.e.
Bildplacering
impact toughness
•
Laser: plate thickness up to 4 mm
•
Laser hybrid: plate thickness up to 10 mm
•
Suitable for:
•
Laser hybrid MIG
Automatic and mechanised welding
How to weld duplex – 26
13
DUPLEX STEELS - Welding methods
Choice of welding method
• Productivity
• Positional welding
• Welder friendly
• Access
How to weld duplex – 27
Deposition rate (kg/h)
DUPLEX STEELS - Welding methods
10
FCW (1,20 m m )
8
MIG (1,20 m m )
6
TIG (2,40 m m )
SAW (dim 3,20 m m )
4
SMAW (3,25 m m )
2
SMAW (4,00 m m )
0
SMAW (5,00 m m )
50 100 150 200 250 300 350 400 450 500
Current (A)
How to weld duplex – 28
14
Method
Plate thickness
MMA
> 1,5 mm
Advantage
Flexibility position
Flexibility grades
Ergonomic
Welding speed
MIG
> 1,5 mm
Cost
Impact toughness
TIG
Productivity
Slag remains
Surface appearance
Parameter adjustment
0,3-3 mm
Surface appearance
Productivity
Root runs
Impact toughness
Shielding and purging gas
Productivity
SAW
Disadvantage
> 10 mm
Surface appearance
No fume and radiation
FCAW
> 2.5 mm
PAW
1-8 mm
Laser
1-8 mm
Lasertohybride
How
weld duplex –4-15
29 mm
High heat input
Only horizontal
Productivity
Fume emission
Wide parameter box
Impact strength
Welding speed
Fit up
Surface appearance
Expensive equipment
Welding speed
Surface appearance
Fit up
Expensive equipment
Productivity
Expensive equipment
Weld metal properties
Parameter set up
DUPLEX STEELS – Shielding gases
Method
Grades
Shielding gas
General guidelines:
MIG
LDX 2101, 2304, 2205
1. Ar+1-2%CO2 or Ar+1-3%CO2
2. Ar+1-2%CO2 or Ar+2-3%CO2
• Gas flow MIG 12-16 l/min
2507/P100
1. Ar+1-2%CO2 or Ar+1-3%CO2
2. Ar
3. Ar+30%He+1-2%N2+1-2%CO2
•Too a low or too a high flow
may result in porosity.
TIG
LDX 2101, 2304,
2205, 2507/P100
1. Ar+10-30%He+2%N2
2. Ar
FCAW
LDX 2101, 2304, 2205
1. Ar+16-25%CO2
2. 100%CO2
Plasma
LDX 2101, 2304,
2205, 2507/P100
1. Ar*
2. Ar+20-30%He+1-2N2*
Laser
LDX 2101, 2304,
2205, 2507/P100
1. Ar
• Gas flow TIG 8-12 l/min
• All methods are sensitive
to draughts.
• Check housing, couplings
etc.
* Also as plasma gas
How to weld duplex – 30
15
DUPLEX STEELS – Backing gases
40
15
MISONN2He
Ar + 3%N2
20
Ar
25
Ar+2%N2
30
Ar (No filler)
Temperature,°C
35
An addition of up to 3%
nitrogen gives a positive
effect on the resistance
to pitting corrosion.
Autogenous welding of
special grades is not
advisable.
10
How to weld duplex – 31
DUPLEX STEELS – Backing gases
Unless pickling is possible an
inert backing must be used
when non-fluxing processes
(TIG and MIG) are employed
for the root run of single side
welds.
The backing provides
protection against oxidation.
If no, or inadequate, protection
is provided the penetration
bead and surrounding metal
will be badly oxidized.
How to weld duplex – 32
16
DUPLEX STEELS – Backing gases
The purging gas is often applied
via:
• Purge insert
• Cardboard or tape
The enclosed volume should
flushed at least 7 times.
The purging gas must be applied
to at least 8 mm of weld metal.
Oxygen meter is best used to
measure the content.
How to weld duplex – 33
DUPLEX STEELS – Backing gases
Acceptance criteria
A straw yellow colour can normally be accepted. This requires a oxygen
content of max 50-60 ppm.
How to weld duplex – 34
17
DUPLEX STEELS – Key to success
Five keys for a successful result
1. Use the right filler metal to achieve right structure = right properties
2. Choose “optimal” welding method for each application
3. Right joint preparation, proper fit-up and clean weld zone
4. Let the welders train how to weld duplex and follow the welding
procedure
5. Chose right and make the post weld cleaning carefully
How to weld duplex – 35
DUPLEX STEELS - Joint preparation
•
Avoid small joint angels
•
Root gap is essential for full penetration
•
Edge preparation:
1. Milling
2. Plasma cutting followed by smooth grinding
3. Grinding the joint shall be avoided
•
Cleaning of the joint after preparation:
• Edge burs
• Degreasing
Keep the joint and plate clean before welding
How to weld duplex – 36
18
DUPLEX STEELS - Joint preparation
FCW, MIG, MMA, TIG
I-joint, t = 2-4 mm
D = 2-2,5 mm
V-joint, t = 4-16 mm
 = 60-70°
C = 1,5-2 mm
D = 2-3,5 mm
FCW welding can be performed using ceramic backing (round type)
D = 4-6 mm
How to weld duplex – 37
DUPLEX STEELS - Joint preparation
FCW, MMA, SAW
X-joint, t = 14-30 mm
 = 60-70° (SAW 80-90°)
D = 2-2,5 mm (SAW 0 mm)
C = 2-2,5 mm (SAW 3-8 mm)

B
C
By choosing X-joint instead of V-joint the consumption of consumables
can decrease be app. 10% and the distortion will be minimised
How to weld duplex – 38
19
DUPLEX STEELS - Joint preparation
Root face 8 mm
16 mm plate
Bevel angel 45
Example SAW 2205, t=16 mm
How to weld duplex – 39
DUPLEX STEELS – Fit-up
• Greater distortion then mild steel
but less than for austenitic steel
• Careful fit-up - keep the root gap!
• Tack welds should be “removed”
before welding
• Avoid misalignment
150-200 mm
How to weld duplex – 40
20
DUPLEX STEELS – Fit-up
• Bridges, bullets or horses can be used
when fitting-up the joint.
Keep the root gap!!
• Tacking of the bridge must be
performed using suitable duplex filler
metal.
• All tacks outside the joint must be
removed by removed properly.
• Disalignment should be avoided
Good tacking is essential for a proper result
Good relation between ”tackers” and welders
How to weld duplex – 41
DUPLEX STEELS – Key to success
Five keys for a successful result
1. Use the right filler metal to achieve right structure = right properties
2. Choose “optimal” welding method for each application
3. Right joint preparation, proper fit-up and clean weld zone
4. Let the welders train how to weld duplex and follow the welding
procedure
5. Chose right and make the post weld cleaning carefully
How to weld duplex – 42
21
DUPLEX STEELS - Temperatures
• Pre-heating not necessary. Welding outside in humid
and cold weather condition requires a slight pre-heating
(max 40°C) to avid moist in the joint
• Interpass temperature max 150°C
• Heat input
2205, 2304
LDX 2101, 2507
0.5 – 3.0 kJ/mm
0.3 – 1.5 kJ/mm
• No post weld heat treatment should be carried out
• Hot forming using flame should be avoided due to risk of
carbon pick-up
How to weld duplex – 43
DUPLEX STEELS - Welding techniques
• Two side welding is easier than one side
unless FCW against ceramic backing is
used
• Visual inspection between each run
• Grinding should be performed between runs
to “open” up the joint (be careful with the
plate surface)
• Grinding of start and stops
• Stringer beads (horizontal)
• Weaving (vertical-up)
• Avoid to thin runs (porosity)
• Protect the weld area from wind and
draught
How to weld duplex – 44
22
DUPLEX STEELS - Welding sequence
Root run
• Sound weld metal
• Full penetration
• Single side runs using MMA or TIG
• TIG requires root protection
Filler runs
• High deposition rate without imperfections
• MMA, FCW, MIG, SAW
Cap runs
• Surface appearance
• Minimum of post weld cleaning
How to weld duplex – 45
DUPLEX STEELS - Welding procedures
Welding Procedure Specification
ELGA AB
Issued by:
Hans Åström
Charge:
Basematerial:
A:
B:
Welding position:
10 mm
10 mm
PA (1G)
Preheat:
B
C
A
C
1
2-3
4-5
Run
1
2-3
4-5
80°
1,5-2,5 mm
Gro up:
B
0,5-1,5 mm
PWHT
N.A.
Backing:
No
Joint prep.
Milled
Filler material
ELGA 2205
ELGA 2205
2205
Dia.
1,6
2,4
3,25
Batch No.
Polarity
Current
Speed
Energy
kJ/mm
0,6-0,8
0,5-0,6
1,4-2,1
Voltage
Ampere
Volt
mm/s
10-12
10-12
20-25
0,8-1,5
1,5-2,5
6-9
1(1)
Date:
2006-05-11
Establish a proper welding
procedure and follow it!
P ipe Ø:
No
°C
Max.150°
°C
°C
h
Notes:
Welding from one side.
Purging gas: Ar (10-15 l/min).
Purging applied for all runs.
Process
GTAW
GTAW
SMAW
60-80
80-110
100-120
Side:
ø400-1000 mm
ø400-1000 mm
Interpass temp.
A
Run
Thickness:
2205 (EN 1.4462)
2205 (EN 1.4462)
WPS No: HÅ155
Gas/Flux
Ar +2% N2 (5-8 l/min)
Pulsed arc Wire feed Note:
m/min
How to weld duplex – 46
23
DUPLEX STEELS – Overlay welding
Duplex filler metals can be used for all types of overlay welding of
carbon steel.
The duplex overlay is resistant to both corrosion and wear
resistance.
The dilution with the carbon steel should be minimised and MMA
and TIG gives generally the lowest dilution.
SAW gives generally a very high dilution and should be avoided.
The dilution can be heavily affected with the welding technique
and parameter set-up.
309L or 309MoL is an cost efficient alternative as first layer.
How to weld duplex – 47
DUPLEX STEELS – Key to success
Five keys for a successful result
1. Use the right filler metal to achieve right structure = right properties
2. Choose “optimal” welding method for each application
3. Right joint preparation, proper fit-up and clean weld zone
4. Let the welders train how to weld duplex and follow the welding
procedure
5. Chose right and make the post weld cleaning carefully
How to weld duplex – 48
24
DUPLEX STEELS – Dissimilar welds
?
X
Z
How to weld duplex – 49
DUPLEX STEELS – Dissimilar welds
SAF 2507
2205
2507
2304
2304
2304
2205
2507
2205
2205
2101
2205
2205
2507
SAF 2507
2507
2507
2507
2507
2101
309MoL
309L
2304
309MoL
309L
2205
309MoL
309L
2507
309MoL
309L
2101
309MoL
625
2304
309MoL
625
2205
309MoL
625
2507
309MoL
625
Carbon
Steel
2205
2304
254 SMO
2304
2101
316
LDX 2101
LDX 2101
304
Grade
2101
309MoL
309L
2304
309MoL
309L
2205
309MoL
309L
2507
309MoL
309L
How to weld duplex – 50
25
Weld defects in DSSDSS
•
Solidification cracking
•
Porosity
•
Slag inclusions
•
Spatter
•
Weld oxides
•
Precipitates
•
•
Sigma phase
Nitrides
Field experience next …..
How to weld duplex – 51
5
How to weld duplex – 52
26
How to weld duplex – 53
How to weld duplex – 54
27
How to weld duplex – 55
How to weld duplex – 56
28
How to weld duplex – 57
DUPLEX STEELS - Be aware of…
The penetration into base material is less for duplex steels than f ex
1.4301 (304) and 1.4401 (316). Risk for incomplete penetration.

Full penetration essential for structural integrity and good properties

2 - 2,5 mm root gap + 30° bevel angle
How to weld duplex – 58
29
DUPLEX STEELS - Be aware of…
The high nitrogen content in base material and consumable increase the
sensitivity for porosity formation compare to 1.4301 (304) and 1.4401 (316).
 To thin or thick beads increase the risk
How to weld duplex – 59
DUPLEX STEELS - Be aware of…
Striking scars, grinding scars, surface oxides, crevice all decreases
the corrosion resistance
 repair welding must be performed using filler
How to weld duplex – 60
30
DUPLEX STEELS - Be aware of…
Too low energy gives high cooling rate 
a high ferrite content and nitrides
 decreased corrosion resistance and toughness
Too high energy gives low cooling rate 
risk for precipitation's of inter metallic phases
 decreased corrosion resistance and toughness
DUPLEX 2304, 2205
max 3 kJ/mm
DUPLEX LDX 2101, 2507
max 1,5 kJ/mm
How to weld duplex – 61
DUPLEX STEELS - Repair
Imperfections must be removed and repair
• Grinding or plasma gauging to sound metal (use stainless tools)
• Protect the surrounding area from spatter (cardboard or choke paint)
• Consider the width and depth
• Penetrant testing
• Welding with suitable method
• Inspection
• Repair can be performed several times without harming the base metal
Establish repair procedure!!
How to weld duplex – 62
31
DUPLEX STEELS - Repair
How to weld duplex – 63
Post weld cleaning - Applications
How to weld duplex – 64
32
DUPLEX STEELS – Key to success
Five keys for a successful result
1. Use the right filler metal to achieve right structure = right properties
2. Choose “optimal” welding method for each application
3. Right joint preparation, proper fit-up and clean weld zone
4. Let the welders train how to weld duplex and follow the welding
procedure
5. Chose right and make the post weld cleaning carefully
How to weld duplex – 65
DUPLEX STEELS - Storage & handling
• Covered electrodes and FCW are sensitive to moist
•
•
Porosity
Bad weld bead apperance
• Product should be stored in original packaging in a moist and heat controlled
room (80%/20°C)
• After use back to package and storage room. No electrodes/FCW/Flux ”over
night”
• Re-drying at 250-280º for 3 hours (SMAW and Flux)
How to weld duplex – 66
33
DUPLEX STEELS - Applications
2205
Civil Engineering
Bridges, crash barriers, rebars, lamp-posts, aerial
masts, flood-gates, beams
2205
LDX 2101
2205
LDX 2101
2304
How to weld duplex – 67
DUPLEX STEELS - Applications
Pressure vessels
Process vessels, heat exchangers, domestic heaters
Process vessel
Domestic
Heat exchanger
heater
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DUPLEX STEELS - Applications
Transportation
Bus frames, car bodies, mobile vessels
Barge tank
Trailer chassis
Chassi
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DUPLEX STEELS - Applications
Heavy Industry
Pipe systems
Continuous
digester
Petro chemical
Sulphuric acid production
Batch digesters
Flue gas cleaning
Papper machine
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DUPLEX STEELS - Applications
Cargo tanks
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DUPLEX STEELS - Applications
Storage tanks
Caustic liquor, petroleum products, wine, water, etc.
Marble slurry tanks, Norway
Palm oil tanks, Netherlands
White liquor tank, Finland
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DUPLEX STEELS - Utilizing strength
Mechanical and physical properties, RT, minimum values
Grade
Rp0.2 [MPa]
Rm [MPa]
E [GPa]
 [x103 kg/m3]
 [x10-6/°C]
304L
210
520
200
7.9
16.0
460
640
200
7.8
13.0
450
650
200
7.7
13.0
2205
(S32205)
LDX 2101
(S32101)
Factors influencing how the strength can be utilized:
• Function – e.g. cylinder with internal pressure
• Constraints:
Shape (diameter, height etc.)
Loading condition (wind loads – instability etc.)
Material standards and design codes (design stresses etc.)
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DUPLEX STEELS - Cost advantage tank
1.4301
LDX
LDX2101
2101
64.9 tons
36.6 tons
m
14
12
Required gauge 1.4301
Required gauge LDX 2101
Min gauge (stability) = 6 mm
10
8
6
4
2
[mm]
Ø 17 m
16
12
8
4
0
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DUPLEX STEELS - Conclusions
• Chose the right filler for the duplex type
• Chose right welding method
• Importance of right joint preparation
• Full penetration
• Slag control
• Control of the melt pool
• Be careful with fit-up and tacking
• Controlled heat input
• Protect the weld area from wind and draught
• Clean weld area
• No pre-heating
• Handling and storage (stainless is sensitive)
• Repair procedures
• Post weld cleaning
Use right filler and follow the welding procedure
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Welding Duplex Stainless Steels
is not difficult just
different
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38
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