Finite Element Investigation of Bauschinger Effect in High-Strength A723 Pressure Vessel Steel

2006 ◽  
Vol 128 (2) ◽  
pp. 185-189 ◽  
Author(s):  
Edward Troiano ◽  
John H. Underwood ◽  
Anthony P. Parker
Keyword(s):  
Finite Element ◽  
Pressure Vessel ◽  
Bauschinger Effect ◽  
High Strength ◽  
Pressure Vessels ◽  
Pressure Vessel Steel ◽  
Test Results ◽  
Vessel Steel ◽  
Reverse Yielding ◽  
The Difference

The Bauschinger effect has been evaluated in high-strength pressure vessels. A simple initial test suggested that a biaxial Bauschinger effect was present and that it was different from previously published uniaxial Bauschinger results. The difference was believed to be significant, so further investigation was undertaken. Several full-size A723 steel gun sections were heavily overstrained and subjected to slit tests in order to measure opening angles and displacements. These geometries were then modeled with finite element (FE) analysis using both ideal autofrettage stresses and Bauschinger modified stresses, which were based on previously published uniaxial Bauschinger test results. Because techniques available for predicting reverse yielding for overstrained pressure vessels were limited, a simple methodology for predicting the yield surface upon reverse yielding from a series of uniaxial Bauschinger test data was developed and is presented. This methodology, when used in the FE predictions, compares favorably with analytical predictions made previously. Comparisons of slit-opening results measured from pressure vessel sections with FE calculations using uniaxial Bauschinger data are made. The opening displacements comparison between the uniaxial predictions and those measured from the heavily overstrained sections with biaxial stresses are so subtle (<1mm) that the tests appear to be inconclusive.

Measurements of Stress During Thermal Shock in Clad Reactor Pressure Vessel Material Using Time-Resolved In-Situ Synchrotron X-Ray Diffraction

2018 ◽  
Author(s):  
Sam Oliver ◽  
Chris Simpson ◽  
Andrew James ◽  
Christina Reinhard ◽  
David Collins ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Pressure Vessel ◽  
Pressure Vessels ◽  
Reactor Pressure Vessel ◽  
Pressure Vessel Steel ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
Vessel Steel ◽  
X Ray ◽  
Reactor Pressure

Nuclear reactor pressure vessels must be able to withstand thermal shock due to emergency cooling during a loss of coolant accident. Demonstrating structural integrity during thermal shock is difficult due to the complex interaction between thermal stress, residual stress, and stress caused by internal pressure. Finite element and analytic approaches exist to calculate the combined stress, but validation is limited. This study describes an experiment which aims to measure stress in a slice of clad reactor pressure vessel during thermal shock using time-resolved synchrotron X-ray diffraction. A test rig was designed to subject specimens to thermal shock, whilst simultaneously enabling synchrotron X-ray diffraction measurements of strain. The specimens were extracted from a block of SA508 Grade 4N reactor pressure vessel steel clad with Alloy 82 nickel-base alloy. Surface cracks were machined in the cladding. Electric heaters heat the specimens to 350°C and then the surface of the cladding is quenched in a bath of cold water, representing thermal shock. Six specimens were subjected to thermal shock on beamline I12 at Diamond Light Source, the UK’s national synchrotron X-ray facility. Time-resolved strain was measured during thermal shock at a single point close to the crack tip at a sample rate of 30 Hz. Hence, stress intensity factor vs time was calculated assuming K-controlled near-tip stress fields. This work describes the experimental method and presents some key results from a preliminary analysis of the data.

The Consequences of Macroscopic Segregation on the Transformation Behavior of a Pressure-Vessel Steel

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
E. J. Pickering ◽  
H. K. D. H. Bhadeshia
Keyword(s):  
Mechanical Properties ◽  
Pressure Vessel ◽  
Large Scale ◽  
Pressure Vessels ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Chemical Segregation ◽  
Compositional Variations ◽  
Grade 3 ◽  
Kinetics Of

It is important that the material used to produce high-integrity pressure vessels has homogeneous properties which are reproducible and within specification. Most heavy pressure vessels comprise large forgings derived from ingots, and are consequently affected by the chemical segregation that occurs during ingot casting. Of particular concern are the compositional variations that arise from macrosegregation, such as the channels of enriched material commonly referred to as A-segregates. By causing corresponding variations in microstructure, the segregation may be detrimental to mechanical properties. It also cannot be removed by any practically feasible heat treatments because of the large scale on which it forms. Here we describe an investigation on the consequences of macrosegregation on the development of microstructure in a pressure-vessel steel, SA508 Grade 3. It is demonstrated that the kinetics of transformation are sensitive to the segregation, resulting in a dramatic spatial variations in microstructure. It is likely therefore that some of the scatter in mechanical properties as observed for such pressure vessels can be attributed to macroscopic casting-induced chemical segregation.

DIROS 500

Alloy Digest ◽  
2011 ◽  
Vol 60 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
Physical Properties ◽  
Pressure Vessel ◽  
High Strength ◽  
Heat Treating ◽  
The Other ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Fine Grained ◽  
Sour Service

Abstract Diros 500 is a fine-grained pressure vessel steel delivered in two grades: one as high strength, the other for sour service. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, and joining. Filing Code: SA-630. Producer or source: Dillinger Hütte GTS.

Mechanical and Physical Properties of a High Strength Pressure Vessel Steel 12Cr2Mo1R

2010 ◽  
Vol 168-170 ◽  
pp. 842-846 ◽  
Author(s):  
Hong Hong Wang ◽  
Ju Zhong Li ◽  
Tian Hui Xi ◽  
Kai Ming Wu
Keyword(s):  
Physical Properties ◽  
Pressure Vessel ◽  
High Strength ◽  
National Standards ◽  
Linear Expansion Coefficient ◽  
Pressure Vessel Steel ◽  
Homogeneous Microstructure ◽  
Vessel Steel ◽  
Iron And Steel ◽  
Mechanical And Physical Properties

12Cr2Mo1R is a high strength pressure vessel steel used in the petrochemical industry. The mechanical and physical properties of the steel 12Cr2Mo1R which was developed in Wuhan Iron and Steel (Group) Company, were investigated in the present work. Test results showed that the steel 12Cr2Mo1R exhibits a high strength at room temperature and high temperature, high strength along Z-direction, and also has very good impact toughness at lower temperatures. The density, linear expansion coefficient and elasticity modulus were also measured. The measured values are all higher than the corresponding specifications of national standards. The uniform mechanical properties and physical properties is attributed to homogeneous microstructure through steel plates.

Research on CCT Curve of 12Cr2Mo1R Pressure Vessel Steel

2014 ◽  
Vol 556-562 ◽  
pp. 468-471
Author(s):  
Min Wang ◽  
Guang Xu ◽  
Hai Lin Yang ◽  
Ming Xing Zhou ◽  
Tao Xiong
Keyword(s):  
Cooling Rate ◽  
Pressure Vessel ◽  
Transformation Temperature ◽  
Pressure Vessel Steel ◽  
Test Results ◽  
Bainite Transformation ◽  
Vessel Steel ◽  
Continuous Cooling Transformation ◽  
Critical Cooling Rate ◽  
Cct Curve

The continuous cooling transformation (CCT) curve of 12Cr2Mo1R pressure vessel steel was measured on Gleeble-1500 hot simulator. The transformation and structures were observed and analyzed. Test results show that with the addition of Cr and Mo, ferrite and perlite transformation temperature increases while bainite transformation temperature decreases, resulting in bainite zone separating from ferrite and pearlite zone. The critical cooling rate for martensite is 30 °C/s.

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.

Mechanisms and Modeling Comparing HB7 and A723 High Strength Pressure Vessel Steels

2004 ◽  
Vol 126 (4) ◽  
pp. 473-477 ◽  
Author(s):  
E. Troiano ◽  
A. P. Parker ◽  
J. H. Underwood
Keyword(s):  
Residual Stresses ◽  
Pressure Vessel ◽  
High Strength ◽  
Strength Level ◽  
Fatigue Properties ◽  
Pressure Vessel Steel ◽  
Cracking Resistance ◽  
Vessel Steel ◽  
Design Engineers ◽  
Vessel Material

HB7, an ultra-clean, high strength pressure vessel steel manufactured in France, is compared to A723 steel. This steel, suggested as an improved pressure vessel material is currently being proposed for critical applications, and will likely be used more frequently as design engineers discover its capabilities. This paper includes comparisons of strength, fracture toughness, fatigue properties and composition of the two steels, followed by an in-depth comparison and modeling of environmental cracking resistance, Bauschinger-modified residual stresses and fatigue lives. Results indicate that in all critical areas, with the exception of Bauschinger-reduced residual stress, the HB7 is superior to the A723 steel. Particularly for small amounts of autofrettage, near-bore residual stresses are reduced for HB7 steel compared to those for A723 steel at the same strength level. The greatest improvement of the HB7 over the A723 is in environmental cracking resistance. The HB7, when tested in concentrated sulfuric acid, exhibits five orders of magnitude longer crack incubation times and three orders of magnitude slower crack growth rates, when compared to A723 steel at the same strength level.

The Consequences of Macroscopic Segregation on the Transformation Behaviour of a Pressure-Vessel Steel

2013 ◽  
Author(s):  
Ed Pickering ◽  
Harry Bhadeshia
Keyword(s):  
Mechanical Properties ◽  
Pressure Vessel ◽  
Pressure Vessels ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Chemical Segregation ◽  
High Integrity ◽  
Compositional Variations ◽  
Grade 3 ◽  
Kinetics Of

It is important that the material used to produce high-integrity pressure vessels has homogeneous properties which are reproducible and within specification. Most heavy pressure vessels comprise large forgings derived from ingots, and are consequently affected by the chemical segregation that occurs during ingot casting. Of particular concern are the compositional variations that arise from macrosegregation, such as the channels of enriched material commonly referred to as A-segregates. By causing corresponding variations in microstructure, the segregation may be detrimental to mechanical properties. Given the scale of the pressure vessel casting, the segregation cannot be removed by practically feasible heat treatments. Here we describe an investigation on the consequences of macrosegregation on the development of microstructure in a pressure-vessel steel, SA508 Grade 3. It is demonstrated that the kinetics of transformation are sensitive to the segregation, resulting in a dramatic spatial variations in microstructure. It is likely therefore that some of the scatter in mechanical properties as observed for such pressure vessels can be attributed to macroscopic casting-induced chemical segregation.

Elaboration and Introduction of the Methodics of Non-Destructive Inspection (Control) of Physical-Mechanical Properties of NPP Pressure Vessels

2004 ◽  
Author(s):  
M. Bakirov ◽  
V. Potapov ◽  
N. Zabruskov ◽  
I. Vystavkin ◽  
V. Levchuk
Keyword(s):  
Mechanical Properties ◽  
Pressure Vessel ◽  
Pressure Vessels ◽  
Full Scale ◽  
Primary Circuit ◽  
Pressure Vessel Steel ◽  
Physical Barrier ◽  
Vessel Steel ◽  
The Third ◽  
Inspection Control

Resource of reactor with PWR is defined, in the first instance, by foundation of integrity of the third physical barrier of safety. The third physical barrier of safety provides a reliable keeping of the coolant in the boundaries of NPP primary circuit. More than thirty year history shows, that reactor vessel is a weak spot in this barrier, the metal of the pressure vessel is subjected to intensive irradiation. The mechanism of operational damage of pressure vessel steel is represented in Fig. 1. This article describes the works, which were conducted by VNIIAES during the last years in the field of elaboration of specimen-free methods and means of inspection (control) of physical-mechanical properties of pressure vessels welds metal of NPPs with PWR. On the base of analysis of that factors, which exercise the most substantial influence on the irradiation embrittlement of pressure vessel materials and on the base of distribution of these factors by degree of significance, there were selected the most appropriate specimen-free methods of inspection: kinetic indentation and kinetic magnetising. It was presented the description of the specimen-free methods, devices and of the results of laboratory measurements, and also the description of the manufacturing procedure and the procedure of certification of the methods on full-scale slabs from WWER-1000 pressure vessel. In the article also is described the example of using of the specimen-free methodics by full-scale inspection (control) of the metal of reactor internal components and of pressure vessel of WWER-1000 of Rostov NPP Unit 1.

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