Evaluation of Alignment Rules Using Stainless Steel Pipes With Non-Aligned Flaws

2009 ◽  
Author(s):  
Kunio Hasegawa ◽  
Katsumasa Miyazaki ◽  
Koichi Saito ◽  
Bostjan Bezensek
Keyword(s):  
Stainless Steel ◽  
Limit Load ◽  
Plastic Collapse ◽  
Paper Briefly ◽  
Limit Loads ◽  
Bending Tests ◽  
Steel Pipes ◽  
Four Point Bending ◽  
Close Proximity ◽  
As Stress

Multiple flaws such as stress corrosion cracks are frequently detected in the same welded lines in pipes. If multiple discrete flaws are in close proximity to one another, alignment rules are used to determine whether the flaws should be treated as non-aligned or as coplanar. Alignment rules are provided in fitness-for-service codes, such as ASME, JSME, API 579, BS 7910, etc. However, the criteria of the alignment rules are different among these codes. This paper briefly introduces these flaw alignment rules, and four-point bending tests performed on stainless steel pipes with two non-aligned flaws. The experimental plastic collapse stresses are determined from the collapse loads and compared with collapse stresses calculated from the limit load criteria. The limit loads are obtained for single non-aligned or aligned coplanar flaws in accordance with the alignment rules. On this basis, the conservatism of the alignment rules in the above codes is assessed.

Experimental Estimation of Fully Plastic Collapse Stresses for Pipes With Three Circumferential Flaws

2009 ◽  
Author(s):  
Fuminori Iwamatsu ◽  
Katsumasa Miyazaki ◽  
Koichi Saito ◽  
Kunio Hasegawa
Keyword(s):  
Stainless Steel ◽  
Limit Load ◽  
Theoretical Method ◽  
Failure Stress ◽  
Experimental Results ◽  
Past Study ◽  
Bending Tests ◽  
Steel Pipes ◽  
Four Point Bending ◽  
As Stress

Fully plastic failure stress for a single circumferential flaw on a pipe is evaluated by the limit load criteria in accordance with Appendix E-8 in the JSME S NA-1-2004 and Appendix C in the ASME Code Section XI. However, multiple flaws such as stress corrosion cracking are frequently detected in the same circumferential cross section in a pipe. Hasegawa had proposed failure stress for pipes with two and three circumferential flaws based on net-stress approach. Authors performed four-point bending tests on stainless steel pipes with two symmetrical circumferential flaws in a past study. It was concluded that the experimental results were in good agreement with the theoretical results. In this study, we performed quasi-static four-point bending tests on stainless steel pipes with three symmetrical circumferential flaws. Each experiment resulted in different fracture behavior. We compared the experimental results with the proposed theoretical method.

Failure Stresses for Pipes With Multiple Circumferential Flaws

2004 ◽  
Author(s):  
Kunio Hasegawa ◽  
Hideo Kobayashi
Keyword(s):  
Stainless Steel ◽  
Limit Load ◽  
Combination Rules ◽  
Steel Pipes ◽  
Ductile Materials ◽  
Asme Code ◽  
As Stress ◽  
Simple Equations ◽  
Service Inspection ◽  
Single Flaw

Flaw evaluation for fully-plastic fracture uses the limit load criterion. As stainless steels are high toughness ductile materials, limit load criterion is applicable to stainless steel pipes. When a single circumferential flaw is detected in a stainless steel pipe during in-service inspection, the single flaw is evaluated in accordance with Article EB-4000 in the JSME Code or Appendix C in the ASME Code, Section XI. However, multiple flaws such as stress corrosion cracking are sometimes detected in the same circumferential cress-section in a pipe. If the distance between adjacent flaws is short, the multiple flaws are considered as a single flaw in compliance with combination rules. Failure stress is easily calculated by the equations given by Article EB-4000 or Appendix C. If the two flaws are separated by a large distance, it is not required to combine the two flaws. Each flaw is treated as independent. However, there are no equations for evaluating collapse stress for a pipe containing multiple independent flaws in Article EB-4000 and Appendix C. The present paper focus on a proposal of simple equations for evaluating collapse stresses for pipes containing multiple circumferential part-through wall flaws.

Estimation of Maximum Load for Pipes With Multiple Circumferential Flaws by Limit Load Analysis

2011 ◽  
Author(s):  
Fuminori Iwamatsu ◽  
Katsumasa Miyazaki ◽  
Koichi Saito ◽  
Tetsuya Hamanaka ◽  
Yoshiaki Takahashi
Keyword(s):  
Limit Load ◽  
Maximum Load ◽  
304 Stainless Steel ◽  
Test Results ◽  
Steel Pipes ◽  
Four Point Bending ◽  
Asme Code ◽  
Load Analysis ◽  
As Stress ◽  
Type 304

Fully plastic failure stress for a single circumferential flaw in a pipe is evaluated by the limit load criteria in accordance with Appendix C in the ASME Code Section XI and Appendix E-8 in the JSME S NA-1-2004. However, multiple flaws such as stress corrosion cracking are frequently detected in the same circumferential cross section in a pipe. Limit load analysis has been validated for pipes with multiple circumferential flaws. Quasi-static four-point bending tests were performed on Type 304 stainless steel pipes with single, double, or triple circumferential flaws. Maximum loads measured in these tests were estimated by limit load analysis for pipes with multiple circumferential flaws. All estimation results using flow stress defined by the JSME S NA-1-2008 are conservative compared to the test results. Estimation results using flow stresses obtained from tests for the pipe with a single flaw quantitatively agree with test results.

Fracture Assessment of Austenitic Stainless Steel Piping With Twin Flaws in TIG Weld

2009 ◽  
Author(s):  
Masao Itatani ◽  
Chihiro Narazaki ◽  
Takahiro Hayashi ◽  
Toshiyuki Saito ◽  
Takuya Ogawa
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Limit Load ◽  
Outer Diameter ◽  
Bending Tests ◽  
Four Point Bending ◽  
Electro Discharge Machining ◽  
Fracture Assessment ◽  
Type 316L Stainless Steel ◽  
Steel Piping

Fracture behavior of austenitic stainless steel piping for boiling water reactor (BWR) internals with circumferential through wall twin flaws at the weld was investigated. A 150A Sch.40 piping of type 316L stainless steel which has an outer diameter of 165.2 mm and a thickness of 7.1 mm was butt welded by tungsten inert gas (TIG) weld and single or twin through wall slits were introduced by an electro discharge machining (EDM) on the weld bead. Four point bending tests were conducted and failure stress was evaluated by currently proposed limit load equation for a piping with multiple flaws. The fracture loads obtained by the test were higher than the limit load based on the recently proposed equation for pipe with multiple flaws using 2.7Sm. It was concluded that the limit load criterion is able to be applied to the fracture assessment of austenitic stainless steel piping with twin flaws in the TIG weld. Through the pipe fracture test, it was found that the crack tends to grow in base metal rather than weld metal.

Prediction of Fully Plastic Collapse Stresses for Pipes With Two Circumferential Flaws

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Kunio Hasegawa ◽  
Koichi Saito ◽  
Fuminori Iwamatsu ◽  
Katsumasa Miyazaki
Keyword(s):  
Evaluation Method ◽  
Limit Load ◽  
304 Stainless Steel ◽  
Plastic Collapse ◽  
Combination Rules ◽  
Steel Pipes ◽  
Asme Code ◽  
As Stress ◽  
Type 304 ◽  
Type 304 Stainless Steel

Fully plastic collapse stress for a single circumferential flaw on a pipe is evaluated by the limit load criteria in accordance with the JSME Code S NA-1-2004 and the ASME Code Section XI. However, multiple flaws such as stress corrosion cracking are frequently detected in the same circumferential cross section in a pipe. If the distance between adjacent flaws is short, the two flaws are combined as a single flaw in compliance with combination rules. If the two flaws separated by a large distance, it is not required to combine two flaws. However, there is no evaluation method for two separated flaws in a pipe in the JSME and ASME Codes. Plastic collapse stresses for pipes with two symmetrical circumferential flaws based on net-stress approach had been proposed by one of the authors. Bending tests were performed on Type 304 stainless steel pipes with two symmetrical circumferential flaws. Consequently, it was shown that the proposed method can predict well the plastic collapse stresses for pipes with two flaws. In addition, it is also shown that this method is appropriate to use in fitness-for-service procedures, and higher plastic collapse stresses are expected, compared with current prediction methods for pipes with two flaws.

Allowable Axial Flaw Sizes for Stainless Steel Pipes Derived From Limit Load Criteria and Failure Assessment Diagram Procedure

2003 ◽  
Author(s):  
Kunio Hasegawa ◽  
Katsumasa Miyazaki ◽  
Gery M. Wilkowski ◽  
Douglas A. Scarth
Keyword(s):  
Stainless Steel ◽  
Limit Load ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Steel Pipes ◽  
Failure Assessment Diagram ◽  
Axial Part ◽  
Wide Range ◽  
Failure Assessment ◽  
Asme Code

Piping containing flaws that exceed the Acceptance Standards of Section XI of the ASME Code is evaluated using analytical procedures described in Section XI to determine plant operability for the evaluated time period. Subarticle IWB-3640 of Section XI provides allowable axial and circumferential part-through-wall flaws determined from limit load criteria. ASME Section XI Code Case N-494-3 also provides evaluation procedures based on use of a failure assessment diagram to determine allowable flaw sizes. To understand the allowable flaw sizes determined by the limit load criteria and the failure assessment diagram procedure, anstenitic stainless steel pipes with axial part-through-wall flaws with a wide range of pipe diameters were analyzed. The allowable flaw depth based on limit load from Code Case N-494-3 was determined to be very close to that determined from IWB-3640 of Section XI, when the predicted failure mode is elastic-plastic fracture. It was found that the allowable flaw depths derived from the failure assessment diagram procedure of Code Case N-494-3, are lower, but are not significantly different, from those determined from the limit load criteria of IWB-3640. This is due to the relatively high fracture toughness that was used for the austenitic stainless steel.

Introduction of CASS Pipe Flaw Evaluation of JSME Rules on Fitness for Service

2019 ◽  
Author(s):  
Kiminobu Hojo
Keyword(s):  
Stainless Steel ◽  
Evaluation Method ◽  
Limit Load ◽  
Evaluation Procedure ◽  
Screening Criteria ◽  
Steel Pipes ◽  
Evaluation Procedures ◽  
Degradation Models ◽  
Fracture Tests ◽  
Cast Stainless Steel

Abstract This paper summarizes the revised flaw evaluation procedures for cast austenitic stainless steel (CASS) pipe of the Japan Society of Mechanical Engineers (JSME) rules on fitness for service (FFS) in 2018 addenda. The revision includes the introduction of thermal aging degradation models for stressstrain curve and fracture resistance (J-R) curve, application of a screening criteria for the fracture evaluation procedure of cast stainless steel pipes, and introduction of a new critical stress parameter for the limit load evaluation method of a shallow flaw with a flaw depth to thickness ratio of less than or equal to 0.5. These revisions are based on a large database of specimen tests and several fracture tests of flat plate and large pipe models using thermally aged material, which have already been published.

Plastic Collapse Stresses for Pipes With Circumferential Twin Flaws Using Combination Rules

2018 ◽  
Author(s):  
Kunio Hasegawa ◽  
Yinsheng Li ◽  
Yun-Jae Kim ◽  
Valery Lacroix ◽  
Bohumir Strnadel
Keyword(s):  
Experimental Data ◽  
Stainless Steel ◽  
Analytical Procedure ◽  
The Other ◽  
Plastic Collapse ◽  
Combination Rules ◽  
Steel Pipes ◽  
Other Hand ◽  
Bending Stresses

When discrete multiple flaws are in the same plane, and they are close to each other, it can be determined whether they are combined or standalone in accordance with combination rules provided by fitness-for-service (FFS) codes, such as ASME, JSME, BS7910, FKM, WES2805, etc. However, specific criteria of the rules are different amongst these FFS codes. On the other hand, plastic collapse bending stresses for stainless steel pipes with circumferential twin flaws were obtained by experiments and the prediction procedure for collapse stresses for pipes with twin flaws were developed analytically. Using the experimental data and the analytical procedure, plastic collapse stresses for pipes with twin flaws are compared with the stresses in compliance with the combination criteria. It is shown that the calculated plastic collapse stresses based on the combination criteria are significantly different from the experimental and analytical stresses.

scholarly journals Development of Braided Carbon/Peek Composite Bone Plates

2001 ◽  
Vol 10 (1) ◽  
pp. 096369350101000 ◽  
Author(s):  
K. Fujihara ◽  
Zheng-Ming Huang ◽  
S. Ramakrishna ◽  
K. Satkunanantham ◽  
H. Hamada
Keyword(s):  
Stainless Steel ◽  
Bending Moment ◽  
Composite Plates ◽  
Bone Plates ◽  
Bending Tests ◽  
Braided Composite ◽  
Four Point Bending ◽  
Peek Composite ◽  
Conventional Stainless Steel ◽  
Composite Bone

In this study, a novel fabrication method using braiding technique was applied to fabricate carbon/PEEK composite bone plates. Four-point bending tests of the composite plates were carried out to compare with the conventional stainless-steel bone plate. The braided composite bone plates with considered braiding angles displayed a maximum bending moment in the range of 38.2 ∼ 44.0 % and bending stiffness in the range of 26.6 ∼ 30.2 % of those of a stainless-steel plate. The bending properties of braided composite plates are comparable with those of the polymer composite bone plates reported in the literature. The potential of braided carbon/PEEK composite material for bone fracture fixation applications is indicated.

Effects of Composite Patch Geometry on Collapse Load of Pressurized Steel Pipes with Internal Longitudinal Flaws

2012 ◽  
Vol 152-154 ◽  
pp. 381-386 ◽  
Author(s):  
Hossein Hosseini-Toudeshky ◽  
Ebrahim Fadaei
Keyword(s):  
Finite Elements ◽  
Limit Load ◽  
Plastic Collapse ◽  
Collapse Load ◽  
Steel Pipes ◽  
Composite Patch ◽  
Offshore Engineering ◽  
Corrosion Defects ◽  
Composite Repairs ◽  
Patch Geometry

Abstract. Internal and/or external corrosions may frequently occur in pressurized pipes in offshore engineering components and many other industries. Corrosion defects reduce the collapse load of pipes, which can be improved by composite repairs. In this article, elastic-plastic finite elements analyses of pressurized repaired pipes with internal longitudinal flaws are performed to obtain the plastic collapse loads of them. The effects of composite patch geometries such as thickness and length on the improved collapse loads of repaired pipes are investigated. It is shown that the limit load of the repaired pipes may reach to the un-defected pipe by increasing the patch thickness (i.e. 25% of flaw depth for the pipe and patch material used in this study).

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