Technical Basis for Flaw Acceptance Criteria for Cast Austenitic Stainless Steel Piping

2017 ◽  
Author(s):  
D. J. Shim ◽  
N. G. Cofie ◽  
D. Dedhia ◽  
D. O. Harris ◽  
T. J. Griesbach ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Ferrite Content ◽  
Evaluation Procedure ◽  
Acceptance Criteria ◽  
Regulatory Guidance ◽  
The Us ◽  
Asme Code ◽  
Tensile Data ◽  
Technical Basis

According to the current ASME Code Section XI, IWB-3640 and Appendix C flaw evaluation procedure, cast austenitic stainless steel (CASS) piping with ferrite content less than 20% is treated as wrought stainless steel. For CASS piping with ferrite content equal or greater than 20%, there is currently no flaw evaluation procedure in the ASME Code. In this paper, the technical basis for a proposed flaw acceptance criteria for CASS piping is presented. The procedure utilizes the current rules in ASME Code Section XI, IWB 3640/Appendix C and the existing elastic-plastic correction factors (i.e., Z-factors) for other materials in the Code. The appropriate Z-factor to use for the CASS piping is determined based on the ferrite content (using Hull’s equivalent factor). Experimentally measured fully saturated fracture toughness and tensile data of the three most common grades of CASS material in the US (CF3, CF8 and CF8M) were used to determine the flaw acceptance criteria in the proposed method. The proposed method is conservative since it utilizes the fully saturated condition of CASS materials. In addition, it is simple and consistent with current regulatory guidance on aging management of CASS piping.

Technical Basis for Flaw Acceptance Criteria for Cast Austenitic Stainless Steel Piping

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
Do Jun Shim ◽  
Nathanial Cofie ◽  
Dilipkumar Dedhia ◽  
Tim Griesbach ◽  
Kyle Amberge
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Evaluation Procedure ◽  
Correction Factors ◽  
Acceptance Criteria ◽  
Regulatory Guidance ◽  
Asme Code ◽  
Tensile Data ◽  
Equivalent Factor ◽  
Technical Basis

Abstract According to the current ASME Code Section XI, IWB-3640 and Appendix C flaw evaluation procedure, cast austenitic stainless steel (CASS) piping with ferrite content (FC) less than 20% is treated as wrought stainless steel. For CASS piping with FC equal or greater than 20%, there was no flaw evaluation procedure in the ASME Code prior to the 2019 Edition. In this paper, the technical basis for the recently approved Code change containing flaw acceptance criteria for CASS piping is presented. The procedure utilizes the current rules in ASME Code Section XI, IWB 3640/Appendix C and the existing elastic-plastic correction factors (i.e., Z-factors) for other materials in the Code. The appropriate Z-factor to use for the CASS piping is determined based on the FC (using Hull's equivalent factor). Experimentally measured fully saturated fracture toughness and tensile data of the three most common grades of CASS material in the U.S. (CF3, CF8, and CF8M) were used to determine the flaw acceptance criteria in the Appendix C Code method. As described here, the method is conservative since it utilizes the fully saturated condition of CASS materials. In addition, it is simple and consistent with the current regulatory guidance on aging management of CASS piping.

scholarly journals Microstructure and Mechanical Properties of Heat-Affected Zone of Repeated Welding AISI 304N Austenitic Stainless Steel by Gleeble Simulator

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 773
Author(s):  
Y.H. Guo ◽  
Li Lin ◽  
Donghui Zhang ◽  
Lili Liu ◽  
M.K. Lei
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Impact Energy ◽  
Heat Affected Zone ◽  
Ferrite Content ◽  
Equipment Safety ◽  
Microstructure And Mechanical Properties ◽  
Δ Ferrite ◽  
The Impact

Heat-affected zone (HAZ) of welding joints critical to the equipment safety service are commonly repeatedly welded in industries. Thus, the effects of repeated welding up to six times on the microstructure and mechanical properties of HAZ for AISI 304N austenitic stainless steel specimens were investigated by a Gleeble simulator. The temperature field of HAZ was measured by in situ thermocouples. The as-welded and one to five times repeated welding were assigned as-welded (AW) and repeated welding 1–5 times (RW1–RW5), respectively. The austenitic matrices with the δ-ferrite were observed in all specimens by the metallography. The δ-ferrite content was also determined using magnetic and metallography methods. The δ-ferrite had a lathy structure with a content of 0.69–3.13 vol.%. The austenitic grains were equiaxial with an average size of 41.4–47.3 μm. The ultimate tensile strength (UTS) and yield strength (YS) mainly depended on the δ-ferrite content; otherwise, the impact energy mainly depended on both the austenitic grain size and the δ-ferrite content. The UTS of the RW1–RW3 specimens was above 550 MPa following the American Society of Mechanical Engineers (ASME) standard. The impact energy of all specimens was higher than that in ASME standard at about 56 J. The repeated welding up to three times could still meet the requirements for strength and toughness of welding specifications.

A Tiered Approach to Girth Weld Defect Acceptance Criteria for Stress-Based Design of Pipelines

2006 ◽  
Author(s):  
Yong-Yi Wang ◽  
Ming Liu ◽  
David Horsley ◽  
Gery Bauman
Keyword(s):  
Test Data ◽  
Plastic Collapse ◽  
Department Of Transportation ◽  
Acceptance Criteria ◽  
Weld Defect ◽  
The Us ◽  
Welding Procedure ◽  
Assessment Procedures ◽  
Technical Basis ◽  
New Procedures

Alternative girth weld defect acceptance criteria implemented in major international codes and standards vary significantly. The requirements for welding procedure qualification and the allowable defect size are often very different among the codes and standards. The assessment procedures in some of the codes and standards are more adaptive to modern micro-alloyed TMCP steels, while others are much less so as they are empirical correlations of test data available at the time of the standards creation. A major effort funded jointly by the US Department of Transportation and PRCI has produced a comprehensive update to the girth weld defect acceptance criteria. The newly proposed procedures have two options. Option 1 is given in an easy-to-use graphical format. The determination of allowable flaw size is extremely simple. Option 2 provides more flexibility and generally allows larger flaws than Option 1, at the expense of more complex computations. Option 1 also has higher fracture toughness requirements than Option 2, as it is built on the concept of plastic collapse. In comparison to some existing codes and standards, the new procedures (1) provide more consistent level of conservatism, (2) include both plastic collapse and fracture criteria, and (3) give necessary considerations to the most frequently occurring defects in modern pipeline constructions. This paper provides an overview of the technical basis of the new procedures and validation against experimental test data.

Life Assessment of Full-Scale EDS Vessel Under Impulsive Loadings

2010 ◽  
Author(s):  
Mien Yip ◽  
Brent Haroldsen
Keyword(s):  
Stainless Steel ◽  
Chemical Treatment ◽  
Maximum Load ◽  
Life Assessment ◽  
Us Army ◽  
Product Manager ◽  
The Us ◽  
Asme Code ◽  
Vessel Response ◽  
Main Component

The Explosive Destruction System (EDS) was developed by Sandia National Laboratories for the US Army Product Manager for Non-Stockpile Chemical Materiel (PMNSCM) to destroy recovered, explosively configured, chemical munitions. PMNSCM currently has five EDS units that have processed over 1,400 items. The system uses linear and conical shaped charges to open munitions and attack the burster followed by chemical treatment of the agent. The main component of the EDS is a stainless steel, cylindrical vessel, which contains the explosion and the subsequent chemical treatment. Extensive modeling and testing have been used to design and qualify the vessel for different applications and conditions. The high explosive (HE) pressure histories and subsequent vessel response (strain histories) are modeled using the analysis codes CTH and LS-DYNA, respectively. Using the model results, a load rating for the EDS is determined based on design guidance provided in the ASME Code, Sect. VIII, Div. 3, Code Case No. 2564. One of the goals is to assess and understand the vessel’s capacity in containing a wide variety of detonation sequences at various load levels. Of particular interest are to know the total number of detonation events at the rated load that can be processed inside each vessel, and a maximum load (such as that arising from an upset condition) that can be contained without causing catastrophic failure of the vessel. This paper will discuss application of Code Case 2564 to the stainless steel EDS vessels, including a fatigue analysis using a J-R curve, vessel response to extreme upset loads, and the effects of strain hardening from successive events.

Development of Analytical Evaluation Procedures and Acceptance Criteria for Pipe Wall Thinning in ASME Code Section XI

2004 ◽  
Author(s):  
Kunio Hasegawa ◽  
Gery M. Wilkowski ◽  
Lee F. Goyette ◽  
Douglas A. Scarth
Keyword(s):  
Pipe Wall ◽  
Evaluation Methodology ◽  
Current Status ◽  
Evaluation Procedure ◽  
Analytical Evaluation ◽  
Acceptance Criteria ◽  
New Class ◽  
Wall Thinning ◽  
Class 1 ◽  
Asme Code

As the worldwide fleet of nuclear power plants ages, the need to address wall thinning in pressure boundary materials becomes more acute. The 2001 ASME Code Case N-597-1, “Requirements for Analytical Evaluation of Pipe Wall Thinning,” provides procedures and criteria for the evaluation of wall thinning that are based on Construction Code design concepts. These procedures and criteria have proven useful for Code Class 2 and 3 piping; but, they provide relatively little flexibility for Class 1 applications. Recent full-scale experiments conducted in Japan and Korea on thinned piping have supported the development of a more contemporary failure strength evaluation methodology applicable to Class 1 piping. The ASME B&PV Code Section XI Working Group on Pipe Flaw Evaluation has undertaken the codification of new Class 1 evaluation methodology, together with the existing Code Case N-597-1 rules for Class 2 and 3 piping, as a non-mandatory Appendix to Section XI. This paper describes the current status of the development of the proposed new Class 1 piping acceptance criteria, along with a brief review of the current Code Case N-597-1 evaluation procedure in general.

Technical Basis for Cases N-629 and N-631 as an Alternative for RTNDT Reference Temperature

2007 ◽  
Author(s):  
J. G. Merkle ◽  
K. K. Yoon ◽  
W. A. VanDerSluys ◽  
W. Server
Keyword(s):  
Pressure Vessel ◽  
Nuclear Power ◽  
Power Plants ◽  
Threshold Level ◽  
Nuclear Regulatory Commission ◽  
New Approach ◽  
The Us ◽  
Asme Code ◽  
Regulatory Commission ◽  
Technical Basis

ASME Code Cases N-629/N-631, published in 1999, provided an important new approach to allow material specific, measured fracture toughness curves for ferritic steels in the code applications. This has enabled some of the nuclear power plants whose reactor pressure vessel materials reached a certain threshold level based on overly conservative rules to use an alternative RTNDT to justify continued operation of their plants. These code cases have been approved by the US Nuclear Regulatory Commission and these have been proposed to be codified in Appendix A and Appendix G of the ASME Boiler and Pressure Vessel Code. This paper summarizes the basis of this approach for the record.

Sign in / Sign up

Export Citation Format

Share Document