Dynamic Ductile Tearing in High Strength Pipeline Steels

1996 ◽  
Author(s):  
F. Rivalin ◽  
A. Pineau
Keyword(s):  
Crack Propagation ◽  
High Strength Steels ◽  
High Strength ◽  
Pearlitic Steel ◽  
Crack Arrest ◽  
Full Scale ◽  
Ductile Crack ◽  
Safety Level ◽  
Dynamic Conditions ◽  
Pipe Burst

The study of rapid ductile crack propagation and crack arrest is a central point if one wants to reach a higher safety level in pipelines. Correlations between Charpy tests and full scale burst tests proved to be unsuccessful in predicting pipe burst for recent high strength steels. This paper presents an experiment which allows to test large SENT specimens under dynamic loading, and to characterize steel resistance against rapid ductile crack propagation by a classical energetic parameter, called the crack propagation energy, R, proposed by Turner. The R parameter proved to be characteristic of the rapid crack propagation in the material, for a given specimen and loading configuration. Failure of the specimen under dynamic conditions occurs by shearing fracture which is the same as in a full scale burst test. An example is given for an X65 ferritic-pearlitic steel loaded under static and dynamic conditions. A fracture mode transition is shown following the loading rate. From a metallurgical point of view, shearing fracture occurs by nucleation, growth and coalescence of voids, as for classical ductile fracture.

Crack Arrest Toughness of Two High Strength Steels (AISI 4140 and AISI 4340)

1982 ◽  
Vol 13 (4) ◽  
pp. 657-664 ◽  
Author(s):  
E. J. Ripling ◽  
J. H. Mulherin ◽  
P. B. Crosley
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Crack Arrest ◽  
Aisi 4140 ◽  
Arrest Toughness ◽  
Aisi 4340

Short Crack Propagation Model Applied to Shot Peened Aluminium Alloys

2009 ◽  
Vol 65 ◽  
pp. 53-61 ◽  
Author(s):  
J. Solis ◽  
J. Oseguera-Peña ◽  
I. Betancourt
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Crack Propagation ◽  
Aluminium Alloys ◽  
Micromechanical Model ◽  
High Strength ◽  
Crack Arrest ◽  
Propagation Model ◽  
Safe Load ◽  
Compressive Residual Stresses

The Navarro-Rios micromechanical model was used to assess the bounds of two different damage zones: crack arrest region and crack propagation region of controlled shot peening (CSP) of high strength aluminium alloys. Performance of CSP in terms of fatigue resistance was investigated. This comparison indicated that CSP in terms of fatigue depends on the competition between its beneficial and detrimental products, i.e. surface roughness and compressive residual stresses respectively. The gathered information can be used for safe load determinations in design.

Fatigue Crack Propagation Limit Curves for S690QL and S960M High Strength Steels and their Welded Joints

2018 ◽  
Vol 1146 ◽  
pp. 44-56 ◽  
Author(s):  
János Lukács ◽  
Ádám Dobosy ◽  
Marcell Gáspár
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Welded Joints ◽  
High Strength Steels ◽  
High Strength ◽  
Base Materials ◽  
Propagation Limit

The objective of the paper is to present the newest results of our complex research work. In order to determination and comparison of the fatigue resistance, fatigue crack growth tests were performed on different grades of S690QL quenched and tempered, and S960TM thermomechanically rolled high strength steels.15 mmand30 mmthick base materials were used for our investigations. Welded joints were made from these base materials, using gas metal arc welding with matching, overmatching, and undermatching filler metals. In the paper, the performance of the welding experiments will be presented, especially with the difficulties of the filler material selection; along with the results of the fatigue crack growth examinations executed on the base materials and its welded joints. Statistical aspects were applied both for the presenting of the possible locations of the cracks in the base materials and the welded joints and for the processing of the measured data. Furthermore, the results will be compared with each other, and the possibility of derivation of fatigue crack propagation limit curves will be referred.

Reliability of Burst Limit States for Damaged and Corroded High Strength Pipelines

2006 ◽  
Author(s):  
Marc A. Maes ◽  
Mamdouh M. Salama ◽  
Markus Dann
Keyword(s):  
Limit State ◽  
High Strength Steels ◽  
High Strength ◽  
Crack Arrest ◽  
Limit States ◽  
Lower Strain ◽  
Margin Of Safety ◽  
Normal Strength ◽  
The Impact

High strength steels (X100 and X120) that are being considered for high pressure gas pipelines differ from conventional steels by exhibiting lower work hardening capacity, lower strain to failure and softening of their HAZ. These differences impact burst limit state and tensile limit state, in addition to crack arrest. In this paper, the impact of the variations in mechanical properties on the reliability of pipe limit states involving ductile burst of damaged or corroded pipe is examined. The paper presents the results of burst limit state analysis using state-of-the-art plastic burst models of strain hardening pipe and considering all the uncertainties that impact the margin of safety of pipes subject to internal pressure. Intact pipes, corroded pipes and externally damaged pipes are considered. A case study comparing the differences between normal strength (X60) pipeline and high strength (X100) pipeline is also presented.

scholarly journals Full-Scale Fracture Propagation Experiments: A Recent Application and Future Use for the Pipeline Industry

2000 ◽  
Author(s):  
D. Michael Johnson ◽  
Peter S. Cumber ◽  
Norval Horner ◽  
Lorne Carlson ◽  
Robert Eiber
Keyword(s):  
Fracture Propagation ◽  
High Strength Steels ◽  
High Strength ◽  
Test Site ◽  
Full Scale ◽  
Operating Conditions ◽  
Test Facility ◽  
Operating Pressure ◽  
Experimental Facility ◽  
The Usa

A full scale fracture propagation test facility has been developed to validate the design, in terms of the ability of the material to avert a propagating fracture, of a major new pipeline to transport gas 1800 miles from British Columbia in Canada to Chicago in the USA. The pipeline, being built by Alliance Pipeline Ltd, will transport rich natural gas, i.e. gas with a higher than normal proportion of heavier hydrocarbons, at a maximum operating pressure of 12,000 kPa. This gas mixture and pressure combination imposes a more severe requirement on the pipe steel toughness than the traditional operating conditions of North American pipelines. As these conditions were outside the validated range of models, two full-scale experiments were conducted to prove the design. This paper will provide details of the construction of the 367m long experimental facility at the BG Technology Spadeadam test site along with the key data obtained from the experiments. Evaluation of this data showed that the test program had validated Alliance’s fracture control design. The decompression data obtained in the experiments will be compared against predictions from a new decompression model developed by BG Technology. The use of the experimental facility and the model to support future developments in the pipeline industry, particularly in relation to the use of high strength steels, will also be discussed.

Fatigue Crack Propagation Limit Curves for High Strength Steels and their Application for Engineering Critical Assessment Calculations

2014 ◽  
Vol 891-892 ◽  
pp. 563-568 ◽  
Author(s):  
János Lukács ◽  
Marcell Gaspar
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Welded Joints ◽  
Research Work ◽  
High Strength Steels ◽  
High Strength ◽  
Critical Assessment ◽  
Propagation Limit

There are different prescriptions containing fatigue crack propagation limit curves and rules for the prediction of the crack growth. The research work aimed (i) to determine fatigue crack propagation limit curves for high strength steels and their welded joints, based on the Paris-Erdogan law; (ii) to use the determined limit curves for engineering critical assessment (ECA) calculations. Experiments were performed on different high strength steels and their welded joints; and the propagating cracks in the specimens represent the different possible locations of the real cracks in the structural elements. Fatigue crack growth tests were executed byΔK-decreasing and constant load amplitude methods. The evaluation process consists of six steps, and by means of the selected values a statistical method can be proposed for determination of the limit curves. Engineering critical assessment calculations were performed on a welded structural element having crack like defects.

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