Transcript A Novel Alloying Concept For Thermo-Mechanical Hot

Development of Niobium-alloyed large diameter pipes
Sandrine Bremer, Volker Flaxa; Salzgitter Mannesmann Forschung GmbH
Franz Martin Knoop; Salzgitter Mannesmann Grossrohr GmbH
London, 7th July 2010
Content
Salzgitter Group
Organisation & Structure
Partners
Motivation
Large diameter line pipe
From ore to pipe
A novel, Nb-containing alloying concept
Microstructure & properties
Benefits of novel steel composition
SZMF/ New Materials and Technologies, Bremer, Slide 2
Technical realisation
Salzgitter Group
• 2008: Crude steel production: 6.9 million tons; trading volume: 6.8 million tons
• Among the top 3 producers of beverage filling und packaging machinery
SZMF/ New Materials and Technologies, Bremer, Slide 3
Global Presence
Salzgitter Group
Group structure and key data FY 2008
Salzgitter AG Group
External Sales cons.: € 12.5 billion
Internal Sales:
€ 3.9 billion
Tubes
Trading
Services
Technology
• Total Sales:
€ 4.3 billion
• Total Sales:
€ 2.9 billion
• Total Sales:
€ 6.3 billion
• Total Sales:
€ 1.3 billion
• Total Sales:
€ 1.0 billion
• External Sales:
€ 3.0 billion
• External Sales:
€ 2.2 billion
• External Sales:
€ 5.6 billion
• External Sales:
€ 0.5 billion
• External Sales:
€ 1.0 billion
• Employees:
6,949
• Employees:
5, 929
• Employees:
1,983
• Employees:
4,003
• Employees:
4,907
All data about employees as per 31/12
SZMF/ New Materials and Technologies, Bremer, Slide 4
Steel
Employees: 23,915
Motivation
The line pipe team
Salzgitter AG Group (Holding)
Salzgitter Mannesmann GmbH – Intermediate holding company
Tubes
MannesmannröhrenWerke GmbH
Trading
Services
Technology
SZMF/ New Materials and Technologies, Bremer, Slide 5
Steel
Salzgitter Stahl GmbH
Motivation
Transport of 51 mio. m3 gas/day
Total length: 2,120 km (1,322 mls)
Start of operation segment 1: 01/2008
Start of operation: 06/2009
Total costs: approx. 4 bn. US$
Salzgitter supply:
168,500 t (ca. 420 km)
1,067 x 14,1 / 18,8 mm
X70, FBE/EP, 18m
SZMF/ New Materials and Technologies, Bremer, Slide 6
High-strength large diameter line pipe
SZMF/ New Materials and Technologies, Bremer, Slide 7
Motivation
High-strength large diameter line pipe
Motivation
High-strength large diameter line pipe
Application of high-strength line pipe steels saves resources and costs!
Increasing operating pressure (from 80 bar to 100 bar) for
constant wall thickness (20 mm)
efficiency 
Reduction of pipe wall thickness (from 20 mm to 18 mm)
for constant operating pressure (80 bar)
pipes` specific weight 
Optimised in-field welding processes for
girth welding
time, material, testing and energy 
75
50
25
Steel grades accor. API 5L:
X60
400
X70
X80
X90
500
Strength [MPa]
600
SZMF/ New Materials and Technologies, Bremer, Slide 8
investment costs for pipe laying 
Weight [%]
shipping 
100
Large diameter line pipe
From ore to pipe
Continuous Casting
Alloyed
 steel
Steel works
Pig iron

 Iron ore
Alloying
stations
LD-Converter
Blast furnace
FerroNiobium
Slab

Spiral pipe mill
Furnace
ø = 508 to 1676 mm
t = 8 to 25 mm
Finishing train
Roughing mill
t = 1.5 to 25 mm
w = 900 to 1,880 mm
l = 100 to 2,000 m
Hot-coiled strip 
SZMF/ New Materials and Technologies, Bremer, Slide 9
Hot rolling mill
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SZMF/ New Materials and Technologies, Bremer, Slide 10
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SZMF/ New Materials and Technologies, Bremer, Slide 11
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SZMF/ New Materials and Technologies, Bremer, Slide 12
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SZMF/ New Materials and Technologies, Bremer, Slide 13
Large diameter line pipe
Steel making „The cooking recipe“
Basic ingredients
Add-ons
Carbon
Nickel
Manganese
Copper
Silicon
Chromium
Molybdenum
Microalloys
Phosphorus
Niobium
Nitrogen
Titanium
Sulphur
Vanadium
Basic ingredients
Microalloys
C
Mn
Si
Nb
V
Ti
Σ Ni + Cu +
Cr + Mo
Standard
0.11
1.75
0.30
0.05
0.10
0.00
≤ 0.10
Novel alloy
0.05
1.80
0.30
0.10
0.00
0.02
> 0.10
Spiral pipes
“API X70”
Add-ons
SZMF/ New Materials and Technologies, Bremer, Slide 14
Tramp elements
Large diameter line pipe
A novel alloying concept: Microstructure & Properties
Effect of high niobium, low carbon addition
Grain refinement if ferrite is present
Two phases (acicular ferrite + lower bainite)
Elimination of pearlite
Many homogenuous distributed precipitations
Standard line pipe
Conclusions
Predominately bainitic microstructure with
many precipitations (for example NbC)
Novel line pipe
SZMF/ New Materials and Technologies, Bremer, Slide 15
Change of dissolution (re-heating) temperature
Large diameter line pipe
A novel alloying concept: Microstructure & Properties
Strength (Tensile testing)
Standard
600
580
D 30 MPa
Novel
D 3 MPa
Standard
Novel
540
Standard
f
Novel
560
Novel
p
Standard
520
Strip Long
Strip Trans
Strip 30°
Pipe Hoop
Conclusions
novel strip 30° = novel pipe hoop
novel pipe > standard pipe
Hot rolling
direction
SZMF/ New Materials and Technologies, Bremer, Slide 16
Yield Strength Rt0.5 [MPa]
620
Large diameter line pipe
A novel alloying concept: Microstructure & Properties
Toughness (Impact testing)
Novel Strip
Novel Pipe
Standard Strip
Standard Pipe
Impact toughness AV [J]
300
250
200
150
100
50
-100
-80
-60
-40
-20
0
Testing temperature [°C]
Conclusions
novel strip & pipe impact energy >
standard strip & pipe impact energy
Hot rolling
direction
SZMF/ New Materials and Technologies, Bremer, Slide 17
0
Benefits of novel steel composition
Conclusions for …
… the steel producer (less costs)
Application of more expensive alloys (for example niobium)
… the spiral pipe mill (competitive advantage)
Comparable welding and seam properties
Optimised strip quality resulting in less repair work on pipes
… the pipe layer (less costs)
Less pipe laying equipment necessary
Saving of welding material and energy
… the gas supplier (increase of efficiency & transmission volume)
Higher operating pressures for similar wall thickness
Light-weight line pipe design possible
SZMF/ New Materials and Technologies, Bremer, Slide 18
Shorter production times leading to capacity increase
Cost reduction
Very smooth processing (increased processing temperatures, less wear)
SZMF/ New Materials and Technologies, Bremer, Slide 19
Many thanks to our excellent line pipe team from all the
divisions involved for their support and help.