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Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Integrity Assessment of Dissimilar Metal Welds
BAY-LOGI
1st Hungarian-Ukrainian Joint Conference on SAFETY-RELIABILITY AND RISK OF ENGINEERING PLANTS AND COMPONENTS”
Szabolcs Szávai Dr. Gyöngyvér B. Lenkey
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
EU5 ADIMEW project’s objectives
Evaluation of conservatism and accuracy of structural integrity assessment methods applied in the European nuclear industry
Study of the behaviour of circumferential surface defect in a dissimilar metal weld
Perform a unique four point bending test of a real size welded structure with crack like defect with normal operation condition
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
BAY-LOGI acitivities in the project Analysis of the effect of notch radius and its
position in the buttering on the structural behaviors
Study the effect of the notch radius on fracture toughness
Study the effect of the defect distance from the fusion line on fracture toughness
Post test modelling of a real size mock-up with crack like defect in the dissimilar weld
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Dissimilar metal weld with crack like deffect
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Fracture toughness determination Felrakóhegesztés
ER Ni Cr 3 Elektródával
Specimen. No. 2.
0
50
100
150
200
250
300
350
400
0,000 0,500 1,000 1,500 2,000 2,500Da-corr, mm
J, k
N/m
CT 25T=300 °C
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Experimental results
0
50
100
150
200
250
300
350
400
0 50 100 150 200 250 300 350
T, °C
J-IC
, kN
/m
r=0.2; d=2
r=0.1; d=2
r=0.2; d=1
r=0.2; d=2
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Conclusions from the test results
The lower toughness value was obtained when the defect was closer to the fusion line (appr. 130 kN/m)
When the defect was farther from the fusion line, the toughness increased significantly(appr. 290 kN/m)
For sharper defect the toughness was lower (appr. 240 kN/m)
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
FE analysis on CT specimen with DMW
To study:– the effect of defect tip radius– the effect of the distance of the defect from the
fusion line– the effect of material properties– comparison of notched and pre-cracked
specimens
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
FEM analysis of CT specimen
StressCheck 6.1
60
25
50
62,5
10
19
308 L; WM
A 508
s
mm
pre-craced nothed
R
mm
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Anyagok valódi feszültség-alakváltozás diagrammja, 300 °C (VTT_2)
0
100
200
300
400
500
600
700
800
900
1000
1100
0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8Eps_p
Seq
(M
Pa)
A508, 300°C_VTT2
316L, 300°C_VTT2
WM, 300°C_VTT2
B
True strain-stress cures, 300°C (VTT)
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Stress and strain distribution in the specimen (F=60kN)
RyWM
RyA508
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Effect of the notch geometry on the CMOD and the strain at the tip
0.000
0.001
0.002
0 10000 20000 30000 40000
Terhelés [N]
CM
OD
[m
]
Előrepesztett
R=0,1mm
R=0,2mm
Mért; R=0,2 mm-re
Eeq(max)-Terhelés; s=2 mm
0
1
2
3
4
5
6
7
8
9
10
0 10000 20000 30000 40000 50000 60000
Terhelés [kN]
Eeq
Előrepesztett
R=0,1 mm
R=0,2 mm
R=0,5 mm
COD-Load(pre-cracked specimen)
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0 10000 20000 30000 40000 50000 60000
Load [kN]
CO
D [
m]
s=0,5 mm
Fusion-Crack
s=2 mm
A508
WM
pre-cracked
pre-cracked
Load
Load
Load
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Conclusions after the FE analysis of CT specimens
the effect of defect tip radius and defect distance on the CMOD values is small
the effect of material properties (i.e. yield stress) on CMOD values is stronger
the effect of defect tip radius on the stress-strain field at the notch tip is significant the effect on the failure load can be significant
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Real size specimen for four point bending test
1 - Austenitic base metal 316 L, 2 - Ferritic base metal A 508, 3 - Dissimilar metal weld 308 L WM, 4 - Prolongation arms (E=206 Gpa, =0.3), 5 - Weld connecting austenitic base metal to prolongation
arm, 6 - Weld connecting ferritic base metal to prolongation arm (E=206 Gpa, =0.3)
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Specimen and the project team
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Test installation at EDF
Outer span : 7m
Inner span : 3m
Maximal load per ram : 2000 kN Maximal ram displacement : 1 m
D
Heating Collars
Heating internal Devices
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Ram displacement without downloads
0
20
40
60
80
100
120
140
160
180
0 3 6 9 12 15 18 21 24
Steps
Ram
dis
pla
cem
ent
[mm
]
DV1
DV2
3000
7000
d=285mm
Pulling collars
Notch Support collar Support collar
Loads and constrains
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Temperature distribution along the pipe
-
50
100
150
200
250
300
-5000 -4000 -3000 -2000 -1000 0 1000 2000 3000 4000 5000
Position on the mock-up (mm)
Te
mp
era
ture
s (
°C)
External - Bottom
External - Top
Mock-up 300°C arms
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Post test analysis of the real size four point bending test
the muck-up is 300 °C the extension arms are approximately at
environmental temperature The crack like defect was shifted from the symmetry
plane with D=285 mm offset (due to the ram displacement control instead of the force control)
The supports were modelled as rigid constrains The elongations of the pulling parts were take into
consideration by application of spring elements in the Fem model
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
FEM model and the calculated stress distribution
CMOD mérés, 10 mm-rel a felület
felett
Elemszám: 35157 Csomópontszám: 42131
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Glue of the different size meshes
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Measured and calculated displacement-load-moment-CMOD curves
Measured and Calculated Ram Displacement-Force Curves
0
200
400
600
800
1000
1200
1400
0 50 100 150
Ram Displacement [mm]
Ram
Fo
rce
[kN
]
FV1_FE
FV2_FE
FV1_Measured
FV2_Measured
Measured and Calculated CMOD-Force Curves
0
200
400
600
800
1000
1200
1400
0 0.5 1 1.5 2 2.5 3 3.5
CMOD O3 [mm]
Ram
Fo
rce
[kN
]
FV1_FE
FV2_FE
FV1_Measured
FV2_Measured
Measured and Calculated CMOD-Moment curves
00.20.40.60.8
11.21.41.61.8
22.2
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
CMOD O3 [mm]
Mo
men
t [M
Nm
]
CMOD_Moment
Measured
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Round-robin results
0
200
400
600
800
1000
1200
0 25 50 75 100 125 150
Dugattyú elmozdulás, mm
Te
rhe
lő e
rő (
du
ga
ttyú
kon
), k
N
FV1 (kN)
FV2 (kN)
FANP2-FV1
FANP2-FV2
GRS FV1
GRS FV2
NRG1-FV1
NRG1 FV2
VUJE FV1
VUJE FV2
BZLOGI-FV1
BZLOGI-FV2
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
Summary and conclusions – post test
Due to the complex geometry huge number of elements and nodes were generated
Results have been compared with the test at some selected points
Ram-force - CMOD values were in good agreement with the calculation
Bay Zoltán Foundation for Applied Reseach
Institute for Logistics and Production Systems BAY-LOGI
General Conclusions
The structure modeling gives appropriate results for further evaluations
For operational safety assessments the fracture mechanical tests are essential
For the validations of the calculation methods structural tests needed