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 CT 25 T=300 °C

Bay Zoltán Foundation for Applied Reseach Institute for Logistics and Production Systems BAY-LOGI Experimental results

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 ,5  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 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)

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 pre-cracked 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

Bay Zoltán Foundation for Applied Reseach Institute for Logistics and Production Systems BAY-LOGI Loads and constrains

Bay Zoltán Foundation for Applied Reseach Institute for Logistics and Production Systems BAY-LOGI Temperature distribution along the pipe 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

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

Bay Zoltán Foundation for Applied Reseach Institute for Logistics and Production Systems BAY-LOGI Round-robin results

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