Flaw Size Acceptance Limits for a Stainless Steel Pressure Vessel

2013 ◽  
Author(s):  
Consuelo E. Guzman-Leong ◽  
Stephen R. Gosselin ◽  
Frederic A. Simonen
Keyword(s):  
Stainless Steel ◽  
Fracture Mechanics ◽  
Failure Mode ◽  
Pressure Vessel ◽  
Pressure Vessels ◽  
Flaw Size ◽  
Ductile Tearing ◽  
Size Acceptance ◽  
Acceptance Levels ◽  
Size Limits

The ASME Boiler and Pressure Vessel Code Section XI provides flaw size acceptance standards for ferritic steel pressure vessels. Section XI Table IWB-3510-1 presents allowable flaw size limits in terms of flaw depth, length and vessel thickness. These flaw size limits are based on linear elastic fracture mechanics calculations that assume a brittle fracture failure mode. As yet, no allowable flaw size standards are provided in Section XI for stainless steel reactor or non-reactor pressure vessels. This paper presents allowable flaw size limits for a stainless steel pressure vessel. These limits were based on elastic plastic fracture mechanics analyses that considered limit load and ductile tearing failure modes. Although the flaw acceptance levels were developed for a specific stainless steel vessel, insights gained from this work may be useful in a general methodology for ASME Code purposes. Tabulated flaw size acceptance levels, for several aspect ratios and inspection intervals, are presented for the axial shell welds. Results show the axial seam welds were the most flaw sensitive of the various welds analyzed. The acceptable flaw sizes were limited by the ductile tearing failure mode.

A Noncyclic Method for Determination of Accumulated Strain in Stainless Steel 304 Pressure Vessels

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Gongfeng Jiang ◽  
Gang Chen ◽  
Liang Sun ◽  
Yiliang Zhang ◽  
Xiaoliang Jia ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Internal Pressure ◽  
Pressure Vessel ◽  
Peak Stress ◽  
Pressure Vessels ◽  
Experimental Results ◽  
Elastic Domain ◽  
Ratcheting Strain ◽  
Stainless Steel 304 ◽  
Accumulated Strain

Experimental results of uniaxial ratcheting tests for stainless steel 304 (SS304) under stress-controlled condition at room temperature showed that the elastic domain defined in this paper expands with accumulation of plastic strain. Both ratcheting strain and viscoplastic strain rates reduce with the increase of elastic domain, and the total strain will be saturated finally. If the saturated strain and corresponded peak stress of different experimental results under the stress ratio R ≥ 0 are plotted, a curve demonstrating the material shakedown states of SS304 can be constituted. Using this curve, the accumulated strain in a pressure vessel subjected to cyclic internal pressure can be determined by only an elastic-plastic analysis, and without the cycle-by-cycle analysis. Meanwhile, a physical experiment of a thin-walled pressure vessel subjected to cyclic internal pressure has been carried out to verify the feasibility and effectiveness of this noncyclic method. By comparison, the accumulated strains evaluated by the noncyclic method agreed well with those obtained from the experiments. The noncyclic method is simpler and more practical than the cycle-by-cycle method for engineering design.

Use of Duplex Stainless Steel in Economic Design of a Pressure Vessel

2006 ◽  
Vol 129 (1) ◽  
pp. 155-161 ◽  
Author(s):  
Milan Veljkovic ◽  
Jonas Gozzi
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Stainless Steels ◽  
Pressure Vessel ◽  
Design Procedure ◽  
High Strength Steels ◽  
High Strength ◽  
Pressure Vessels ◽  
Economic Design ◽  
European Standard

Pressure vessels have been used for a long time in various applications in oil, chemical, nuclear, and power industries. Although high-strength steels have been available in the last three decades, there are still some provisions in design codes that preclude a full exploitation of its properties. This was recognized by the European Equipment Industry and an initiative to improve economy and safe use of high-strength steels in the pressure vessel design was expressed in the evaluation report (Szusdziara, S., and McAllista, S., EPERC Report No. (97)005, Nov. 11, 1997). Duplex stainless steel (DSS) has a mixed structure which consists of ferrite and austenite stainless steels, with austenite between 40% and 60%. The current version of the European standard for unfired pressure vessels EN 13445:2002 contains an innovative design procedure based on Finite Element Analysis (FEA), called Design by Analysis-Direct Route (DBA-DR). According to EN 13445:2002 duplex stainless steels should be designed as a ferritic stainless steels. Such statement seems to penalize the DSS grades for the use in unfired pressure vessels (Bocquet, P., and Hukelmann, F., 2001, EPERC Bulletin, No. 5). The aim of this paper is to present an investigation performed by Luleå University of Technology within the ECOPRESS project (2000-2003) (http://www.ecopress.org), indicating possibilities towards economic design of pressure vessels made of the EN 1.4462, designation according to the European standard EN 10088-1 Stainless steels. The results show that FEA with von Mises yield criterion and isotropic hardening describe the material behaviour with a good agreement compared to tests and that 5% principal strain limit is too low and 12% is more appropriate.

Accounting for the Effects of Inservice Inspection Flaw Depth Sizing Errors in Developing Flaw Size Distribution Tables

2009 ◽  
Author(s):  
S. R. Gosselin ◽  
F. A. Simonen
Keyword(s):  
Pressure Vessel ◽  
Pressure Vessels ◽  
Reactor Pressure Vessel ◽  
Expert Elicitation ◽  
Flaw Size ◽  
Physical Models ◽  
Asme Code ◽  
Valid Comparison ◽  
Vessel Material ◽  
Reactor Pressure

Probabilistic fracture mechanics studies have addressed reactor pressure vessels that have high levels of material embrittlement. These calculations have used flaw size and density distributions determined from precise and optimized laboratory measurements made and validated with destructive methods as well as from physical models and expert elicitation. The experimental data were obtained from reactor vessel material samples removed from cancelled plants (Shoreham and the Pressure Vessel Research Users Facility (PVRUF)). Consequently, utilities may need to compare the numbers and sizes of reactor pressure vessel flaws identified by the plant’s inservice inspection program to the numbers and sizes of flaws assumed in prior failure probability calculations. This paper describes a method to determine whether the flaws in a particular reactor pressure vessel are consistent with the assumptions regarding the number and sizes of flaws used in other analyses. The approach recognizes that ASME Code Section XI examinations suffer from limitations in terms of sizing errors for very small flaws. Direct comparisons of a vessel specific flaw distribution with other documented flaw distributions would lead to pessimistic conclusions. This paper provides a method for a valid comparison that accounts for flaw sizing errors present in ASME Code Section XI examinations.

Fracture Assessments of High Pressure Vessel Components Having Longitudinal Holes

2017 ◽  
Author(s):  
Yu Xu ◽  
Kuao-John Young
Keyword(s):  
High Pressure ◽  
Stress Concentration ◽  
Fracture Mechanics ◽  
Pressure Vessel ◽  
High Stress ◽  
Pressure Vessels ◽  
Crack Face ◽  
High Pressure Vessel ◽  
High Stress Concentration ◽  
Critical Locations

Small size longitudinal holes are common in components of high pressure vessels. In fracture mechanics evaluation, longitudinal holes have not drawn as much attention as cross-bores. However, longitudinal holes become critical at certain locations for such assessments because of high stress concentration and short distance to vessel component wall. The high stress concentration can be attributed to three parts: global hoop stress that is magnified by the existence of the hole, local stresses due to pressure in the hole, and crack face pressure. In high pressure vessel design, axisymmetric models are used extensively in stress analyses, and their results are subsequently employed to identify critical locations for fracture mechanics evaluation. However, axisymmetric models ignore longitudinal holes and therefore cannot be used to identify the critical location inside the holes. This paper is intended to highlight the importance of including longitudinal holes in fracture mechanics evaluation, and to present a quick and effective way of evaluating high stress concentration at a longitudinal hole using the combined analytical solutions and axisymmetric stress analysis results, identifying critical locations and conducting fracture mechanics evaluation.

Options for Defining the Upper Shelf Transition Temperature (Tc) for Ferritic Pressure Vessel Steels

2015 ◽  
Author(s):  
Mark Kirk ◽  
Gary Stevens ◽  
Marjorie Erickson ◽  
William Server ◽  
Hal Gustin
Keyword(s):  
Fracture Mechanics ◽  
Pressure Vessel ◽  
Ductile Tearing ◽  
Temperature Range ◽  
Linear Elastic ◽  
A Value ◽  
Pressure Vessel Steels ◽  
Elastic Fracture ◽  
Current Guidance ◽  
Definition Of

This paper evaluates current guidance concerning conditions under which the analyst is advised to transition from a linear-elastic fracture mechanics (LEFM) based analysis to an elastic-plastic fracture mechanics (EPFM) based analysis of pressure vessel steels. Current guidance concerning the upper-temperature (T>c) for LEFM-based analysis can be found in ASME Section XI Code Case N-749. Also, while not explicitly stated, an upper-limit on the KIc value that may be used in LEFM-based evaluations is sometimes taken to be 220 MPa√m (a value herein referred to as KLIM). Evaluations of Tc and KLIM were performed using a recently compiled collection of toughness models that are being considered for incorporation into a revision to ASME Section XI Code Case N-830; those models provide a complete definition of all toughness metrics needed to characterize ferritic steel behavior from lower shelf to upper shelf. Based on these evaluations, new definitions of Tc and KLIM are proposed that are fully consistent with the proposed revisions to Code Case N-830 and, thereby, with the underlying fracture toughness data. Formulas that quantify the following values over the ranges of RTTo and RTNDT characteristic of ferritic RPV steels are proposed: • For Tc, two values, Tc(LOWER) and Tc(UPPER), are defined that bound the temperature range over which the fracture behavior of ferritic RPV steels transitions from brittle to ductile. Below Tc(LOWER), LEFM analysis is acceptable while above Tc(UPPER) EPFM analysis is recommended. Between Tc(LOWER) and Tc(UPPER), the analyst is encouraged to consider EPFM analysis because within this temperature range the competition of the fracture mode combined with the details of a particular analysis suggest that the decision concerning the type of analysis is best made on a case-by-case basis. • For KLIM, two values, KLIM(LOWER) and KLIM(UPPER), are defined that bound the range of applied-K over which ductile tearing will begin to occur. At applied-K values below KLIM(LOWER), ductile tearing is highly unlikely, so the use of the KIc curve is appropriate. At applied-K values above KLIM(UPPER), considerable ductile tearing is expected, so the use of the KIc curve is not appropriate. At applied-K values in between KLIM(LOWER) and KLIM(UPPER), some ductile tearing can be expected, so it is recommended to give consideration to the possible effects of ductile tearing as they may impact the situation being analyzed. These definitions of Tc and KLIM better communicate important information concerning the underlying material and structural behavior to the analyst than do current definitions.

Acoustic Emission Testing During a Burst Test of a Thick-Walled 2-1/4 Cr-1 Mo Steel Pressure Vessel

1980 ◽  
Vol 102 (4) ◽  
pp. 353-362 ◽  
Author(s):  
T. Tsukikawa ◽  
S. Yamamoto ◽  
Y. Ohshio ◽  
M. Nakano ◽  
H. Ueyama ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fracture Mechanics ◽  
Pressure Vessel ◽  
Pressure Vessels ◽  
Burst Test ◽  
Test Vessel ◽  
Emission Testing ◽  
Acoustic Emission Testing ◽  
Extensive Program

The applicability of AET to pressure vessels made of 2 1/4 Cr-1 Mo steel was studied by an extensive program which included: 1) a hydrostatic test of a test vessel with weld discontinuities, 2) a burst test of a test vessel with precracks, and 3) an analysis of the results using a fracture mechanics approach. The results obtained clearly demonstrate that AET is a useful tool for shop and in-field inspections.

Calculation and Analysis for Pressure Vessel Rupture Study Under Fire in Plant

2016 ◽  
Author(s):  
Yoshiyasu Ito ◽  
Akira Tsuruoka ◽  
Yoshiyuki Waki ◽  
Hiroko Osedo
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Pressure Vessel ◽  
Oil And Gas ◽  
Fem Analysis ◽  
Pressure Vessels ◽  
Design Guidelines ◽  
Plant Design ◽  
System Pressure ◽  
Vessel Rupture

In case of fire occurring in an Oil and Gas facility, pressurized vessels may be exposed to fire. Though the entire system will be depressurized once a fire is detected, vessels may rupture, leading to risk of flammable, toxic or cryogenic fluid being released. Therefore, pressure vessels should be designed to withstand internal pressure without rupture in fire situations, at least until the system pressure can be decreased to a safe level. A pressure vessel rupture study should be conducted in addition to design code calculation to ensure a safe design in case of fire. As part of the recent trend for safer plant design, demand for pressure vessel rupture studies is growing. In our previous presentation (PVP2015-45260 [1]), the material data for carbon steel (SA-516 Gr.70) and stainless steel (SA240 SUS type304 and SUS type304L) at the high temperature range were obtained by material testing and presented as our study result. For the present research, pressure vessel rupture studies were performed for carbon steel and stainless steel using FEM analysis and calculation methods in published design guidelines for various conditions (e.g. heating area and shell thickness, etc.). In conclusion, a procedure for pressure vessel rupture study is proposed.

Supplemental Stress and Fracture Mechanics Analyses of Pressurized Water Reactor Pressure Vessel Nozzles

2012 ◽  
Author(s):  
Matthew Walter ◽  
Shengjun Yin ◽  
Gary L. Stevens ◽  
Daniel Sommerville ◽  
Nathan Palm ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Pressure Vessel ◽  
Pressure Vessels ◽  
Reactor Pressure Vessel ◽  
Additional Stress ◽  
Corner Crack ◽  
Pressurized Water ◽  
The Core ◽  
Water Reactors ◽  
Reactor Pressure

In past years, the authors have undertaken various studies of nozzles in both boiling water reactors (BWRs) and pressurized water reactors (PWRs) located in the reactor pressure vessel (RPV) adjacent to the core beltline region. Those studies described stress and fracture mechanics analyses performed to assess various RPV nozzle geometries, which were selected based on their proximity to the core beltline region, i.e., those nozzle configurations that are located close enough to the core region such that they may receive sufficient fluence prior to end-of-life (EOL) to require evaluation of embrittlement as part of the RPV analyses associated with pressure-temperature (P-T) limits. In this paper, additional stress and fracture analyses are summarized that were performed for additional PWR nozzles with the following objectives: • To expand the population of PWR nozzle configurations evaluated, which was limited in the previous work to just two nozzles (one inlet and one outlet nozzle). • To model and understand differences in stress results obtained for an internal pressure load case using a two-dimensional (2-D) axi-symmetric finite element model (FEM) vs. a three-dimensional (3-D) FEM for these PWR nozzles. In particular, the ovalization (stress concentration) effect of two intersecting cylinders, which is typical of RPV nozzle configurations, was investigated. • To investigate the applicability of previously recommended linear elastic fracture mechanics (LEFM) hand solutions for calculating the Mode I stress intensity factor for a postulated nozzle corner crack for pressure loading for these PWR nozzles. These analyses were performed to further expand earlier work completed to support potential revision and refinement of Title 10 to the U.S. Code of Federal Regulations (CFR), Part 50, Appendix G, “Fracture Toughness Requirements,” and are intended to supplement similar evaluation of nozzles presented at the 2008, 2009, and 2011 Pressure Vessels and Piping (PVP) Conferences. This work is also relevant to the ongoing efforts of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code, Section XI, Working Group on Operating Plant Criteria (WGOPC) efforts to incorporate nozzle fracture mechanics solutions into a revision to ASME B&PV Code, Section XI, Nonmandatory Appendix G.

Sign in / Sign up

Export Citation Format

Share Document