Applicability of the ASME Exemption Curve for Chinese Pressure Vessel Steel Q345R

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Qingfeng Cui ◽  
Hu Hui ◽  
PeiNing Li
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Impact Test ◽  
Pressure Vessels ◽  
Uniaxial Tensile ◽  
Assessment Procedure ◽  
Pressure Vessel Steel ◽  
Fracture Toughness Test ◽  
Vessel Steel ◽  
The Impact

Q345R steel is the most commonly used material in fabrication of the pressure vessels and boilers in China, due to its excellent properties. In 2010, ASME code case 2642 accepted Q345R steel for use in construction of pressure vessels. The code case specified impact test exemption curve A for the impact test requirements for Q345R. However, this provision severely limits the application of this material at low temperature, since most of the minimum design metal temperature (MDMT) of curve A is above the freezing point. In this paper, a series of tests (such as uniaxial tensile test, impact test, and fracture toughness test) were carried out at low temperature to investigate the mechanical properties of Q345R steel plates with thickness of 36–80 mm. This study of low temperature usage of Q345R steel was conducted using the fracture mechanics assessment procedure of API 579-1/ASME FFS-1. The fracture toughness is given by master curve (MC) method in the transition regime. The results show that Q345R can be used at lower temperature and that classifying Q345R steel into curve D is appropriate.

Toughness Requirement of Chinese Pressure Vessel Steel 07MnNiMoDR Based on Fracture Mechanics Assessment Method

2018 ◽  
Author(s):  
Lele Gui ◽  
Tong Xu ◽  
Yonghui Sun ◽  
Xuexin Shang
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Fracture Mechanics ◽  
High Strength ◽  
Assessment Method ◽  
Pressure Vessels ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Master Curve Method ◽  
Tension Tests

07MnNiMoDR is a widely used quenched and tempered high strength steel in fabrication of low-temperature pressure vessels in China. It can be used at/above −50°C according to the current design specification of GB 150. Some data show that this provision severely underestimates the performance of this material at low temperature, while others indicate that it overestimates the cryogenic performance of this material. In the paper, a series of tests including uniaxial tension tests, impact test and fracture toughness tests were carried out at low temperature to investigate the properties of 07MnNiMoDR with different thickness specimens. Fracture mechanics assessment procedures in API 579-1/ASME FFS-1 (Fitness-For-Service) is adopted to evaluate the low temperature design curve of 07MnNiMoDR, and the fracture toughness is obtained by master curve method (MC method) in the transition region. The results show that 07MnNiMoDR can be classified between exemption curve B and D in current edition of ASME Section VIII, Division 2.

Applicability of Miniature C(T) Specimen to Evaluation of Fracture Toughness for Reactor Pressure Vessel Steel

2013 ◽  
Author(s):  
Kentaro Yoshimoto ◽  
Takatoshi Hirota ◽  
Hiroyuki Sakamoto ◽  
Takuji Sugihara ◽  
Shohei Sakaguchi ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Evaluation Method ◽  
Pressure Vessels ◽  
Charpy Specimen ◽  
Pressure Vessel Steel ◽  
Fracture Toughness Test ◽  
Irradiation Embrittlement ◽  
Vessel Steel ◽  
Reactor Pressure Vessel Steel ◽  
Reactor Pressure

Irradiation embrittlement of Japanese reactor pressure vessels (RPV) is usually monitored by conducting tests on irradiated RPV material according to surveillance test program. Although fracture toughness specimens are contained in Japanese PWR surveillance capsule, the number of specimens is limited due to capacity of capsule. In order to evaluate lower bound of fracture toughness considering its scatter with higher reliability, it is expected to obtain additional fracture toughness data using remaining broken specimens of irradiated materials. One of solutions to this problem is specimen reconstitution technique. However, it is difficult to make numbers of specimens by reconstitution because of need for specific equipments and time-consuming machining operations. As an alternative method, fracture toughness test using miniature C(T) specimens with dimension of 4×10×10mm, which can be taken from broken halves of Charpy specimen, is proposed and the studies to verify the reliability and robustness of evaluation method have been conducted in the Japanese round robin program since 2010. In this study, fracture toughness tests were performed on Japanese SA 533 Gr.B Cl.1 steel using miniature C(T) specimens and the effect of specimen size on reference temperature T0 was studied by the Master Curve approach. In addition, the issues related to application to irradiated materials were discussed.

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.

Experimental Study on the Cleavage Fracture Behavior of an ASTM A285 Grade C Pressure Vessel Steel

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Rafael G. Savioli ◽  
Claudio Ruggieri
Keyword(s):  
Fracture Toughness ◽  
Cleavage Fracture ◽  
Pressure Vessel ◽  
Fracture Behavior ◽  
Pressure Vessels ◽  
Experimental Results ◽  
Pressure Vessel Steel ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Vessel Steel

This work addresses an experimental investigation on the cleavage fracture behavior of an ASTM A285 Grade C pressure vessel steel. One purpose of this study is to enlarge previously reported work on mechanical and fracture properties for this class of steel to provide a more definite database for use in structural and defect analyses of pressurized components, including pressure vessels and storage tanks. Another purpose is to determine the reference temperature, T0, derived from the Master curve methodology which defines the dependence of fracture toughness with temperature for the tested material. Fracture toughness testing conducted on single edge bend SE(B) specimens in three-point loading extracted from an A285 Grade C pressure vessel steel plate provides the cleavage fracture resistance data in terms of the J-integral and crack tip opening displacement (CTOD) at cleavage instability, Jc and δc. Additional tensile and conventional Charpy tests produce further experimental data which serve to characterize the mechanical behavior of the tested pressure vessel steel. The experimental results reveal a strong effect of specimen geometry on Jc and δc-values associated with large scatter in the measured values of cleavage fracture toughness. Overall, the present investigation, when taken together with previous studies, provides a fairly extensive body of experimental results which describe in detail the fracture behavior of an ASTM A285 Grade C pressure vessel steel.

Analysis of Crack Front Length Effect Applicable to the Evaluation of Fracture Toughness of Base Metal for PWR Pressure Vessel Steel

2014 ◽  
Author(s):  
Pierre Joly ◽  
Claude Benhamou ◽  
Antoine Andrieu ◽  
Henriette Churier-Bossenec ◽  
Aurore Parrot
Keyword(s):  
Fracture Toughness ◽  
Size Effect ◽  
Base Metal ◽  
Crack Front ◽  
Pressure Vessel ◽  
Pressure Vessel Steel ◽  
Fracture Toughness Test ◽  
Reference Curve ◽  
Length Effect ◽  
Vessel Steel

The objective of the present paper is to review the crack front length effect (also called “specimen size effect”) on Fracture Toughness of PWR Reactor Pressure Vessel Steel base metal. The analysis of the reality and amplitude of this effect is conducted in a first step on a database (the so called “GKSS database”) including fracture toughness test results on a single representative material using specimens of different thicknesses, tested in the same temperature range. A realistic analytical form for describing the size effect observed in this data set is thus derived from statistical analyses and proposed for engineering application. In a second step, this size effect formulation is then applied to a large number of fracture toughness data, obtained in Irradiation Surveillance Programs, and also to the numerous data used for the definition of the ASME (and RCC-M) fracture toughness reference curves. This analysis allows normalizing all the available fracture toughness data with a single specimen width of 100 mm and defining the fracture toughness reference curve as the lower bound of this normalized set of data points. It is thus demonstrated that the fracture toughness reference curve is associated with a reference crack length of 100 mm, and can be used in RPV integrity analyses for other crack front length in association with the crack front length correction formula defined in the first step.

Comparison of Predicted Transition Temperature Shifts Between Static Fracture Toughness and Charpy-V Impact Properties Due to Irradiation for an A508 Pressure Vessel Steel

2004 ◽  
Author(s):  
B. Tanguy ◽  
J. Besson ◽  
C. Bouchet ◽  
S. Bugat
Keyword(s):  
Fracture Toughness ◽  
Pressure Vessel ◽  
Material Model ◽  
Pressure Vessel Steel ◽  
Fracture Toughness Test ◽  
Irradiation Embrittlement ◽  
Charpy Test ◽  
Vessel Steel ◽  
Rupture Energy ◽  
Reference Index

Nuclear pressure vessel steels are subjected to irradiation embrittlement which is monitored using Charpy tests. Reference index temperatures, such as the temperature for which the mean Charpy rupture energy is equal to 56 J (T56J), are used as embrittlement indicators. The safety integrity evaluation is performed assuming that the shift of RTNDT due to irradiation is equal to the shift of T56J. In this work a material model integrating a description of viscoplasticity, ductile damage and brittle fracture is used to simulate both the Charpy test and the fracture toughness test (CT geometry). The model is adjusted on an unirradiated material. It is then applied to irradiated materials assuming that irradiation affects hardening. It is shown that irradiation probably also affects brittle failure. The shift of RTNDT and the predicted shift of T100MPam are then compared for a given level of irradiation.

BISALLOY STRUCTURAL 80 PRESSURE VESSEL STEEL

Alloy Digest ◽  
2019 ◽  
Vol 68 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Yield Strength ◽  
Pressure Vessel ◽  
High Strength ◽  
Pressure Vessel Steel ◽  
Low Carbon ◽  
Vessel Steel ◽  
Temperature Fracture ◽  
Minimum Yield

Abstract Bisalloy Structural 80 Pressure Vessel Steel (80 ksi minimum yield strength) is a low-carbon, low-alloy, high-strength structural steel for pressure vessel applications. It exhibits excellent cold formability and low-temperature fracture toughness. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on forming, machining, and joining. Filing Code: SA-844. Producer or source: Bisalloy Steels Group Limited.

Evaluation of Quasi-Static and Dynamic Fracture Toughness on the Low-Alloy Reactor Pressure Vessel Steel JRQ in the Transition Region

2019 ◽  
Vol 827 ◽  
pp. 294-299
Author(s):  
Philippe Spätig ◽  
V. Mazánová ◽  
S. Suman ◽  
Hans Peter Seifert
Keyword(s):  
Fracture Toughness ◽  
Transition Region ◽  
Dynamic Fracture ◽  
Dynamic Fracture Toughness ◽  
Pressure Vessels ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Master Curve Method ◽  
Reactor Pressure Vessel Steel ◽  
Reactor Pressure

Three point bending and impact tests with sub-sized Charpy specimens were performed on the JRQ reference steel for reactor pressure vessels. Quasi-static and dynamic fracture toughness data were calculated and the fracture behavior in the ductile to brittle transition region was evaluated within the frame of the master curve method (ASTM E1921). Specimens with shallow and deep cracks were studied and the respective influence of crack length and loading rate on the reference transition temperature was determined. The force-time curves of specimens with shallow cracks presented significantly smaller oscillations with respect to the absolute force, making the fracture toughness evaluation more accurate.

Large SA-508 Class 2 Nozzle Forging Near-Surface Fracture Toughness

2017 ◽  
Author(s):  
J. Brian Hall ◽  
Benjamin E. Mays ◽  
Matthew DeVan
Keyword(s):  
Fracture Toughness ◽  
Transition Temperature ◽  
Lower Bound ◽  
Master Curve ◽  
Impact Test ◽  
Temperature Limit ◽  
Pressure Vessels ◽  
Fracture Toughness Test ◽  
Test Technique ◽  
Near Surface

The current approach in evaluating the Pressurized Water Reactor (PWR) inlet and outlet nozzle corner regions with respect to plant heat-up and cool-down pressure-temperature limit curves contains a number of conservatisms. These conservatisms include postulation of a large ¼ thickness flaw at the nozzle corner region and use of RTNDT (reference nil-ductility temperature) or an estimation of RTNDT. The paper herein discusses generic fracture toughness of nozzle forging material SA-508 Class 2 for use with postulated smaller surface flaws in developing pressure-temperature limit curves for nozzle corners for nuclear power plant operations. ASME Appendix G uses the lower bound KIC curve, which has inherent margin since RTNDT is a conservative method for locating the KIC curve. RTNDT is based on the drop weight test, which is a crack arrest transition temperature measurement, and the Charpy impact test, which is a blunt notch impact test. These data are conservatively bounded by the KIC curve, which is a lower bound crack initiation toughness curve. In contrast, the master curve method is based on an initiation transition temperature fracture toughness test technique per ASTM E1921. The master curve index temperature (T0) provides a more accurate measure of the material fracture toughness than KIC indexed with RTNDT. Since many of the nuclear pressure vessels were fabricated to ASME Code editions prior to 1972, RTNDT was not measured for the nozzles. In many cases, RTNDT has been estimated. Therefore, for this work, the fracture toughness was generically established based on conservative T0 measurements of 22 representative forgings with a margin of two standard deviations to ensure a conservative lower bound toughness using ASME Appendix G, G-2110. The properties of a forging are better near the surface due to the faster cooling rate during heat treatment. The difference in reactor pressure vessel fracture toughness was established for forgings near the surface at the postulated flaw location as allowed by ASME Section III, NB-2223.2 relative to the traditional ¼ thickness location. The near-surface forging toughness was conservatively determined through evaluation of 31 near-surface and approximate ¼ thickness location fracture toughness measurements.

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