Metalurgie - Comparatie Oteluri Termomecanice Cu Cele Conventionale
Transcript of Metalurgie - Comparatie Oteluri Termomecanice Cu Cele Conventionale
Comparison of Thermomechanical Rolledwith Conventional Steels
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12.01.2010 Comparison of TM and N-steels
Advantages of TM-steel
• Properties–Analysis–Toughness
• Economics–Processing advantages, Preheating–Reduction of weight
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12.01.2010 Comparison of TM and N-steels
S 460 NL S 460 ML
acc. EN 10025-3
Auxiliary Data
acc. EN 10025-4
Auxiliary Data
C < 0,20 0,17 < 0,16 0,09 Si < 0,60 0,45 < 0,60 0,30 Mn 1,00 - 1,70 1,65 < 1,70 1,50 P < 0,030 0,015 < 0,030 0,011 S < 0,025 0,010 < 0,025 0,005
Nb < 0,05 - < 0,05 < 0,04 V < 0,20 0,17 < 0,12 < 0,05
Mo < 0,10 - < 0,20 - Ni < 0,80 0,29 < 0,45 0,25 CE 0,50 0,39
Pcm 0,29 0,20 CET 0,34 0,28
Carbon equivalents: CE = C + Mn/6 + (Cr + Mo + V)/5 + (Ni+Cu)/15 Pcm = C +Si/30 + (Mn + Cu + Cr)/20 + Ni/60 + Mo/15 + V/10 + 5B CET = C + (Mn + Mo)/10 + (Cr + Cu)/20 + Ni/40
TM Low carbon content
Plate thickness 50 mm
Advantages of TM-steel - Analysis
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12.01.2010 Comparison of TM and N-steels
a) N b) Q+T
Microstructures for different process routes (exemplary)
c) TM d) TM+ACC
20 µm
20 µm 20 µm
20 µm
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Typical carbon equivalents and microstructures for normalised and thermomechanical rolled steels
100
200
300
400
500
600
700
0,20 0,25 0,30 0,35 0,40 0,45Ceq
min
. YS
in M
Pa
Ceq = C + Mn/6 +(Mo+Cr+V)/5 + (Cu+Ni)/15
normalizedS355N
TMS355M
20 µm
0.20 0.25 0.30 0.35 0.40 0.45
20 µm
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12.01.2010 Comparison of TM and N-steels
TM High toughness / High safety
-120 -100 -80 -60 -40 -20 0 200
50
100
150
200
250
300
350 S355J2+N S460ML S690QL
Cha
rpy-
V [J
]
Temperature [°C]
Welding leads to
toughness
reduction
High toughnessin the base
material reducesthe risk of brittle
fracture and gives saftey!
Advantages of TM-steel - toughness
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12.01.2010 Comparison of TM and N-steels
TM Cost efficiency – Low preheating
Advantages of TM-steel - Processing advantages
Low preheating temperatures are not only a matter of costs!Also in terms of job safety, low preheating temperatures are beneficial!
NO HOT SURFACES / NO HANDLING WITH GAS / BETTER WORKING CONDITIONS
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EN 1011-2:Recommendations for arc welding of ferritic steels
( ) 328Q32CET53HD6235dtanh160CET697T 35.0
p −×−×+×+⎟⎠⎞
⎜⎝⎛×+×=
Preheating is necessary to avoid: excessive hardening
Preheating is necessary to avoid: cold cracking
Advantages of TM-steel - Preheating
TM Low carbon content / Low preheating
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EN 1011-2:Recommendations for arc welding of ferritic steels
( ) 328Q32CET53HD6235dtanh160CET697T 35.0
p −×−×+×+⎟⎠⎞
⎜⎝⎛×+×=
Tp - Preheating temperature [°C]CET - Carbon equivalent [%]: CET = C + (Mn + Mo)/10 + (Cr + Cu)/20 + Ni/40d - Plate thickness [mm]HD - Hydrogen content [cm³/100 g]Q - Heat input [kJ/mm]
Preheating is necessary to avoid: excessive hardening
Preheating is necessary to avoid: cold cracking
Advantages of TM-steel - Preheating
TM Low carbon content / Low preheating
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0 20 40 60 800
2
4
6
8
10
75°C
50°C
25 °C
typisc he r B ereichfür H2 Geh alte
S355M S460M
Plate thickness [mm]
Hyd
roge
nco
nten
tof w
eldi
ngco
nsum
able
[cm
3 /100
g]H
ydrogencontentof w
eldingconsum
able[cm
3/100g]
0 20 40 6 0 800
2
4
6
8
1 0
100 °C
7 5°C
50 °C
25°C
typisch er B ereichfür H2 Geh alte
Plate thickness [mm]
Calculated with Q = 2.5 kJ/mm (submerged arc welding) and for typical CET´s
Advantages of TM-steel - Preheating
TM Low carbon content / Low preheating
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Avoiding
preheating1. No installations
No setting up timeNo gas
TM Cost efficiency – Low preheating
Advantages of TM-steel - Preheating
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Reducing preheating
temperatures2. Gas consumption ↓
Heating time ↓
Avoiding
preheating1. No installations
No setting up timeNo gas
TM Cost efficiency – Low preheating
Advantages of TM-steel - Preheating
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12.01.2010 Comparison of TM and N-steels
Reducing preheating
temperatures2. Gas consumption ↓
Heating time ↓
Avoiding
preheating1. No installations
No setting up timeNo gas
Biggest potentialfor reducing costs
TM Cost efficiency – Low preheating
Advantages of TM-steel - Preheating
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12.01.2010 Comparison of TM and N-steels
Reducing preheating
temperatures2. Gas consumption ↓
Heating time ↓
Often underestimated,but worth to think about
Avoiding
preheating1. No installations
No setting up timeNo gas
Biggest potentialfor reducing costs
TM Cost efficiency – Low preheating
Advantages of TM-steel - Preheating
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Sauertal Bridge (Germany)
Box-girder-bridgeLength: 1195 mWidth: 27 m11 Spans: 75 – 150 mTonnage: 13,000 tGrade: S355J2+N
3000 t > 25 mm thickness
TM Cost efficiency – Low preheating
Advantages of TM-steel - Preheating
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12.01.2010 Comparison of TM and N-steels
Alternative:
S355J2+N > S355MNo preheating
150,000 €C = A - BBENEFIT
75,000 €B = 3,000 x 25 €/tB) Additional costs S355M (25 €/t)
225,000 €A = 30,000 h x 15 % x 50 €/hA) Saving preheating times
Conditions:
30,000 h welding time15 % for preheating50 €/h labour costs
TM Cost efficiency – Low preheating
Advantages of TM-steel - Preheating
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12.01.2010 Comparison of TM and N-steels
S355NL
S355ML
changingdeliverycondition
t1
t2
t1 = t2
TM Cost efficiency – Low preheating
Advantages of TM-steel - Reduction of weight
Possibility to avoid preheating!• no gas consumption• no set-up times• higher capacity in the work shop
0,2 0,3 0,4 0,5-50
0
50
100
150
200
250
T p C
ET [°
C]
Carbon equivalent CET [%]
EN 1011-2:TpCET = 750 x CET – 1500.01% CET ca. 7.5°C
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12.01.2010 Comparison of TM and N-steels
TM Cost efficiency – High strength
S460NL
S355NL
increasingyield
strength
t
t
A
A,B ~ t2
Wel
ding
cos
ts
Plate thickness
~ t²
• Weight reduction (ca. 30%)• Bigger assembling units possible• Less holding times in the workshop• Less welding consumables• Reduction of welding time• Reduction of testing time
t1
t2
t2 < t1
Advantages of TM-steel - Reduction of weight
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12.01.2010 Comparison of TM and N-steels
S460NL73 mm
73 mm
S355NL fy = 315 Mpa100 mm
S460ML
increasingyield
strength
changingdeliverycondition
TM Cost efficiency – High strength TM
Advantages of TM-steel - Reduction of weight
• Weight reduction (ca. 30%)• Bigger assembling units possible• Less holding times in the workshop• Less welding consumables• Reduction of welding time• Reduction of testing time
• Avoiding/Reducing preheating• Better weldability• High toughness reserves
=> High safety
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12.01.2010 Comparison of TM and N-steels
Thank youfor your
attention!