Validation of the Master Curve Approach With Various Welding Conditions: Groove Shapes, Heat Inputs and Welding Processes

2020 ◽  
Author(s):  
Jin Ho Lee ◽  
Ji Hoon Kim ◽  
Myung Hyun Kim
Keyword(s):  
Fracture Toughness ◽  
Master Curve ◽  
Impact Test ◽  
Structural Integrity ◽  
Charpy Impact ◽  
Test Sample ◽  
Charpy Impact Test ◽  
Theoretical Background ◽  
Reference Temperature ◽  
Welding Processes

Abstract Engineering critical assessment (ECA) is a procedure for evaluating the soundness of structures with flaws and has been widely applied for assessing the structural integrity. ECA procedure requires reliable fracture toughness data to assess the effect of defects. Ideal data are typically obtained from samples taken during construction of an engineering structure or from the structure afterward, but there are cases in which removal of the test samples is impossible due to the continued operation of the structure. To this end, Appendix J of the BS 7910 provides a procedure for estimating fracture toughness values from appropriate Charpy impact test data. However, the correlation between Charpy impact energy and fracture toughness is known to be overly conservative with not sufficient theoretical background in fracture mechanics perspective. In this regard, the revised BS 7910:2019 provides an improved method for calculating the reference temperature by applying the yield strength and the Charpy upper shelf energy based on empirical data. The target of this study is to validate the master curve approach in the modified BS 7910 for two common offshore grade steels with explicit considerations for various groove shapes, heat inputs and welding processes. For the purpose, the master curves are compared in terms of the reference temperature calculated from Charpy impact test according to BS 7910:2013 and the newly revised 2019 version of BS 7910. The modified master curve resulted in less conservative fracture toughness values anticipated from the decreased reference temperature. The estimated fracture toughness values exhibited a good correlation with experimentally obtained toughness values. The influence of various groove shapes, heat inputs and welding processes in estimating fracture toughness based on the master curve approach is discussed. In addition, the effect of impact test sample locations within weld metals toward estimated fracture toughness values is evaluated.

A method for directly measuring fracture toughness and determining reference temperature for RPV steels by Charpy impact test

2021 ◽  
Vol 243 ◽  
pp. 107526
Author(s):  
Chenglong Wang ◽  
Zhenfeng Tong ◽  
Weihua Zhong ◽  
Hu Lin ◽  
Guangsheng Ning ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Reference Temperature

Evaluation of Brittle Crack Arrest Toughness for Highly-Irradiated Reactor Pressure Vessel Steels

2021 ◽  
Author(s):  
Keiko Iwata ◽  
Kuniki Hata ◽  
Tohru Tobita ◽  
Takatoshi Hirota ◽  
Hisashi Takamizawa ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Pressure Vessel ◽  
Impact Test ◽  
Charpy Impact ◽  
Crack Arrest ◽  
Charpy Impact Test ◽  
Reactor Pressure Vessel ◽  
Reference Temperature ◽  
Arrest Toughness ◽  
Reactor Pressure

Abstract The crack arrest fracture toughness, KIa, values for highly-irradiated reactor pressure vessel (RPV) steels are estimated according to the linear relationship between crack arrest toughness reference temperature, TKIa, and the temperature corresponding to a fixed arrest load, equal to 4 kN, TFa4kN, obtained by instrumented Charpy impact test. The relationship between TKIa derived from the instrumented Charpy impact test and fracture toughness reference temperature, To, was expressed as an equation proposed in a previous study. The coefficients in the equation could be fine-tuned to obtain a better fitting curve using the present experimental data and previous KIa data. The KIa curve for RPV;A533B class 1 steels irradiated up to 1.3 × 1020 n/cm2 (E > 1 MeV) was compared with a KIR curve defined in JEAC4206-2016. The KIR curve was always lower than the 1%ile curve of KIa for these irradiated RPV steels. This result indicates that the conservatism of the method defined in JEAC4206-2016 to evaluate KIa using the KIR curve is confirmed for highly-irradiated RPV steels.

scholarly journals The Charpy Impact Test of Rock (2nd Report)-Dynamic Fracture Toughness-

2006 ◽  
Vol 18 (1/2) ◽  
pp. 15-20
Author(s):  
Mitsumasa FURUZUMI ◽  
Fumio SUGIMOTO ◽  
Tadao IMAI ◽  
Naoto KAMOSHIDA ◽  
Masayoshi ABE
Keyword(s):  
Fracture Toughness ◽  
Dynamic Fracture ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Dynamic Fracture Toughness

Fracture Toughness Transferability Study Between the Master Curve Method and a Pressure Vessel Nozzle Using Local Approach

2003 ◽  
Author(s):  
Anssi Laukkanen ◽  
Pekka Nevasmaa ◽  
Heikki Keina¨nen ◽  
Kim Wallin
Keyword(s):  
Fracture Toughness ◽  
Pressure Vessel ◽  
Master Curve ◽  
Structural Integrity ◽  
Reference Temperature ◽  
Cleavage Crack ◽  
Local Approach ◽  
Master Curve Method ◽  
Curve Method ◽  
Constitutive Parameters

Local approach methods are to greater extent used in structural integrity evaluation, in particular with respect to initiation of an unstable cleavage crack. However, local approach methods have had a tendency to be considered as methodologies with ‘qualitative’ potential, rather than quantitative usage in realistic analyses where lengthy and in some cases ambiguous calibration of local approach parameters is not feasible. As such, studies need to be conducted to illustrate the usability of local approach methods in structural integrity analyses and improve upon the transferability of their intrinsic, material like, constitutive parameters. Improvements of this kind can be attained by constructing improved models utilizing state of the art numerical simulation methods and presenting consistent calibration methodologies for the constitutive parameters. The current study investigates the performance of a modified Beremin model by comparing integrity evaluation results of the local approach model to those attained by using the constraint corrected Master Curve methodology. Current investigation applies the Master Curve method in conjunction with the T-stress correction of the reference temperature and a modified Beremin model to an assessment of a three-dimensional pressure vessel nozzle in a spherical vessel end. The material information for the study is extracted from the ‘Euro-Curve’ ductile to brittle transition region fracture toughness round robin test program. The experimental results are used to determine the Master Curve reference temperature and calibrate local approach parameters. The values are then used to determine the cumulative failure probability of cleavage crack initiation in the model structure. The results illustrate that the Master Curve results with the constraint correction are to some extent more conservative than the results attained using local approach. The used methodologies support each other and indicate that with the applied local approach and Master Curve procedures reliable estimates of structural integrity can be attained for complex material behavior and structural geometries.

Evaluation of Fracture Toughness From Instrumented Charpy Impact Tests for a Reactor Pressure Vessel Steel

2003 ◽  
Author(s):  
A. Parrot ◽  
P. Forget ◽  
A. Dahl
Keyword(s):  
Fracture Toughness ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Impact Tests ◽  
Reactor Pressure Vessel Steel ◽  
Ductile To Brittle Transition ◽  
Reactor Pressure

The monitoring of neutron induced embrittlement of nuclear power plants is provided using Charpy impact test in the surveillance program. However structural integrity assessments require the fracture toughness. Some empirical formulas have been developed but no direct relationship was found. The aim of our study is to determine the fracture toughness of a Reactor Pressure Vessel steel from instrumented Charpy impact test using local approach to fracture. This non-empirical method has been applied in the brittle domain as well as in the ductile to brittle transition for an A508 C1.3 steel. In the brittle domain, fracture occurs by cleavage and can be modeled with the Beremin model. Fracture toughness has been successfully determined from Charpy impact tests results and the influence of several parameters (mesh design, Beremin model with one or two parameters, number of Charpy impact tests results) on the results was considered. In the ductile to brittle transition, cleavage fracture is preceded by ductile crack growth. Ductile tearing has been accounted for in the simulations with the Rousselier model whereas cleavage fracture is still described with the Beremin model. The determination of fracture toughness from Charpy impact tests gave encouraging results but finite element simulations have to be refined in order to improve predictions.

scholarly journals Prediction of fracture toughness KIc of steel from Charpy impact test results.

1986 ◽  
Vol 35 (395) ◽  
pp. 873-879
Author(s):  
Tadao IWADATE ◽  
Yasuhiko TANAKA ◽  
Hiroyuki TAKEMATA ◽  
Shuhei TERASHIMA
Keyword(s):  
Fracture Toughness ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Test Results

The Charpy Impact Test as an Evaluation of 4 K Fracture Toughness

Materials ◽  
1992 ◽  
pp. 207-215 ◽  
Author(s):  
H. Nakajima ◽  
K. Yoshida ◽  
H. Tsuji ◽  
R. L. Tobler ◽  
I. S. Hwang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test

Thermal Aging Behavior of Grade CF3M Cast Austenitic Stainless Steels

2017 ◽  
Author(s):  
Yasufumi Miura ◽  
Takashi Sawabe ◽  
Kiyoshi Betsuyaku ◽  
Taku Arai
Keyword(s):  
Fracture Toughness ◽  
Stainless Steels ◽  
Thermal Aging ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Ferrite Phase ◽  
Absorbed Energy ◽  
Aging Conditions ◽  
Charpy Absorbed Energy

In this study, CASSs which were thermally aged at 275–400°C for up to 30000 hrs were investigated using atom probe tomography, Charpy impact test, hardness test, and fracture toughness test in order to evaluate the effects of chemical composition and ferrite content on thermal aging embrittlement. Test materials were 4 types of statically casted grade CF3M stainless steels which are used in Japanese BWR plants. As a result of the tests, Charpy absorbed energy at room temperature of all thermal aging conditions were obtained. We also obtained the microstructural evolution in ferrite phase, hardness of ferrite phase, and J–R curves of several aging conditions. The fracture toughness and the Charpy absorbed energy of all materials aged at 275°C for up to 15000 hrs were approximately same as those of unaged materials. On the other hand, reduction of the fracture toughness and the Charpy absorbed energy were observed in the materials aged at 300°C, 320°C, 350°C and 400°C. For the Charpy impact test in this study, the absorbed energy of the material with highest molybdenum was lower than that of the material with highest ferrite content. After the tests, the fracture toughness estimation model for grade CF8M in NUREG/CR-4513 and the method in PVP2005-71528 (H3T model) were discussed in order to confirm the applicability of the prediction methods to CF3M.

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