Applicability of Existing Models for Predicting Ductile Fracture Arrest in High Pressure Pipelines

2006 ◽  
Author(s):  
John Wolodko ◽  
Mark Stephens
Keyword(s):  
High Pressure ◽  
Ductile Fracture ◽  
High Pressures ◽  
Fracture Propagation ◽  
High Strength Steels ◽  
High Strength ◽  
Full Scale ◽  
Stage Of Development ◽  
Fracture Arrest ◽  
Arrest Toughness

The ductile fracture arrest capability of gas pipelines is seen as one of the most important factors in the future acceptance of new high strength pipeline steels for high pressure applications. It has been acknowledged for some time that the current methods for characterizing and predicting the arrest toughness for ductile fracture propagation in high strength steels are un-conservative. This observation is based on the inability of existing models to predict the required arrest toughness in full-scale ductile fracture propagation tests. While considerable effort is currently being applied to develop more accurate methods for predicting ductile facture arrest, the resulting models are still in a preliminary stage of development and are not immediately amenable for use by the general engineering community. As an interim solution, a number of authors have advocated the empirical adjustment or reformulation of the existing models for use with the newer, high strength pipe grades. While this approach does not address the fundamental issues surrounding the fracture arrest problem, it does provide methods that can be used in the near term for analysis and preliminary design. The desire to use these existing methods, however, is tempered by the uncertainty associated with their applicability in situations involving high pressures and/or high toughness materials. In an attempt to address some of these concerns, a statistical analysis was conducted to assess the accuracy of a number of available fracture arrest models by comparing predictions to actual values determined from full-scale fracture propagation experiments. From the results, correction factors were developed for determining the required toughness levels in high pressure applications that account for the uncertainty in the theoretical prediction methods.

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.

Mechanical and Metallurgical Aspects of the Resistance to Ductile Fracture Propagation in the New Generation of Gas Pipelines

2014 ◽  
Author(s):  
Igor Pyshmintsev ◽  
Alexey Gervasyev ◽  
Victor Carretero Olalla ◽  
Roumen Petrov ◽  
Andrey Arabey
Keyword(s):  
Ductile Fracture ◽  
Mechanical Test ◽  
Fracture Propagation ◽  
Rolling Plane ◽  
Full Scale ◽  
Charpy Test ◽  
Line Pipe ◽  
Surface Separation ◽  
Fracture Arrest ◽  
New Generation

The microstructure and fracture behavior of the base metal of different X80 steel line pipe lots from several pipeline projects were analyzed. The resistance of the pipes to ductile fracture propagation was determined by the full-scale burst tests. The high intensity of fracture surface separation (secondary brittle cracks parallel to the rolling plane of the plate) appeared to be the main factor reducing the specific fracture energy of ductile crack propagation. A method for quantitative analysis of microstructure allowing estimation of the steel’s tendency to form separations is proposed. The procedure is based on the EBSD data processing and results in Cleavage Morphology Clustering (CMC) parameter evaluation which correlates with full-scale and laboratory mechanical test results. Two special laboratory mechanical test types utilizing SENT and Charpy test concepts for prediction of ductile fracture arrest/propagation in a pipe were developed and included into Gazprom specifications.

Qualification Strategy for FAST-Pipe™ for High Pressure Gas Pipelines

2010 ◽  
Author(s):  
Mamdouh M. Salama
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Glass Fibers ◽  
Large Diameter ◽  
High Strength Steels ◽  
High Strength ◽  
Operational Parameters ◽  
Conventional Steel ◽  
Bending Load ◽  
Analysis Strategy

Because major reserves for natural gas are often remotely located from potential market, its transportation requires larger diameter pipes operating at high pressures. In order to reduce cost, high strength steels (≥ X80) have been advanced to reduce the wall thickness of the pipeline and thus lower materials, transportation and construction costs. However, producing large diameter high pressure pipelines of these steels creates significant challenges that can only be met by very few steel suppliers. This paper presents the qualification results of an alternative technology that will reduce cost even more than high strength steels while using conventional steel such as X70. This technology, which is designated as Fiber Augmented Steel Technology Pipe (FAST-Pipe™), involves hoop winding dry glass fibers over conventional steel pipes (e.g. X70) to provide the required high pressure capacity. The steel thickness is selected to mainly satisfy axial and bending load requirements. Following a proof-of-concept of the FAST-Pipe™, a detailed qualification program was developed based on a decision and risk analysis strategy that incorporates key elements of the industry technology qualification guidelines (DNV RP A203 and API 17N). The qualification program involved addressing fifteen design, construction and operational parameters. The paper presents the FAST-Pipe™ concept, discusses its advantages and summarizes the results of its qualification program.

Review of Fracture Control Technology for Gas Transmission Pipelines

2014 ◽  
Author(s):  
Xian-Kui Zhu
Keyword(s):  
Ductile Fracture ◽  
Fracture Propagation ◽  
High Strength ◽  
Fracture Initiation ◽  
Alternative Methods ◽  
Opening Angle ◽  
Pipeline Steels ◽  
Control Plan ◽  
Fracture Control ◽  
Arrest Toughness

A fracture control plan is often required for a gas transmission pipeline in the structural design and safe operation. Fracture control involves technologies to control brittle and ductile fracture initiation, as well as brittle and ductile fracture propagation for gas pipelines, as reviewed in this paper. The approaches developed forty years ago for the fracture initiation controls remain in use today, with limited improvements. In contrast, the approaches developed for the ductile fracture propagation control has not worked for today’s pipeline steels. Extensive efforts have been made to this topic, but new technology still needs to be developed for modern high-strength pipeline steels. Thus, this is the central to be reviewed. In order to control ductile fracture propagation, Battelle in the 1970s developed a two-curve model (BTCM) to determine arrest toughness for gas pipeline steels in terms of Charpy vee-notched (CVN) impact energy. Practice showed that the BTCM is viable for pipeline grades X65 and below, but issues emerged for higher grades. Thus, different corrections to improve the BTCM and alternative methods have been proposed over the years. This includes the CVN energy-based corrections, the drop-weight tear test (DWTT) energy-based correlations, the crack-tip opening angle (CTOA) criteria, and finite element methods. These approaches are reviewed and discussed in this paper, as well as the newest technology developed to determine fracture arrest toughness for high-strength pipeline steels.

Existing Methods in Ductile Fracture Propagation Control for High-Strength Gas Transmission Pipelines

2013 ◽  
Author(s):  
Xian-Kui Zhu
Keyword(s):  
Fracture Toughness ◽  
High Pressure ◽  
Ductile Fracture ◽  
Engineering Design ◽  
Fracture Propagation ◽  
High Strength ◽  
Control Analysis ◽  
Battelle Memorial Institute ◽  
Pipeline Steels ◽  
Transmission Pipelines

Ductile fracture propagation control is one of the most important technologies adopted in engineering design for high-pressure, high-strength gas transmission pipelines. In the early 1970s, Battelle Memorial Institute developed a two-curve model that is now commonly referred to as BTCM for dynamic ductile fracture control analysis. The BTCM has been applied successfully for determining the minimum fracture toughness required to arrest a running ductile fracture in a gas transmission pipeline in terms of Charpy vee-notched (CVN) impact energy. Practice showed that BTCM is accurate only for pipeline grades up to X65, and becomes invalid for high strength pipeline steels like X70, X80 and X100. Since 1990s, different correction methods for improving the BTCM have been proposed. However, a commonly accepted method is not available yet for the high strength pipeline steels in grades X80 and above. This paper reviews and evaluates the primary existing methods in determination of fracture arrest toughness for ductile pipeline steels. These include the CVN energy-based methods, the drop-weight tear test (DWTT) energy-based methods, the crack-tip opening angle (CTOA) method, and finite element numerical analysis methods. The purpose is to identify a method to be used in engineering design or to be investigated further for determining the minimum fracture toughness to arrest a ductile running crack in a modern high-pressure, high-strength gas pipeline.

Modified Two-Curve Model for Predicting Fracture Arrest Toughness and Arrest Distance of Full-Size Burst Tests

2016 ◽  
Author(s):  
Xian-Kui Zhu
Keyword(s):  
Test Data ◽  
Pipeline Steel ◽  
Large Diameter ◽  
High Strength ◽  
Full Scale ◽  
Burst Test ◽  
Pipe Segment ◽  
Single Pipe ◽  
Fracture Arrest ◽  
Arrest Toughness

Running fracture control is a very important technology for gas transmission pipelines with large diameter and high pressure. The Battelle two-curve (BTC) model developed in the early 1970s has been widely used in pipeline industry to determine arrest toughness in terms of the Charpy energy. Because of its semi-empirical nature and calibration with test data only for grades up to X65, the BTC does not work for higher grades. Simple corrections were thus proposed to extend the BTC model to higher grades, but limited to those grades considered. Moreover, the BTC model only predicts the minimum arrest toughness, but not arrest distance. To fill the technical gaps, this paper proposes a modified two-curve (MTC) model and a fracture arrest distance model in reference to the Charpy energy. The MTC model coupling with an arrest distance algorithm can predict fracture arrest toughness and arrest distance in one simulation of numerical integration for a single pipe or a set of multiple pipes with given toughness. Two sets of full-scale burst test data for X70 and X80 are used to validate the proposed model, and the results show good agreements between the predictions and full-scale test data of arrest toughness and arrest distance as well. The MTC model is then applied to optimize a design of pipe segment arrangements for a mockup full-scale burst test on a high-strength pipeline steel. The MTC simulation results confirm the experimental observation that different pipe arrangements determine different arrest toughness and arrest distance for the same grade pipes.

Fracture Propagation and Arrest in High-Pressure Gas Transmission Pipeline by Ultra High Strength Line Pipes

2008 ◽  
Author(s):  
Hiroyuki Makino ◽  
Izumi Takeuchi ◽  
Ryouta Higuchi
Keyword(s):  
High Pressure ◽  
Crack Velocity ◽  
Shear Fracture ◽  
Fracture Propagation ◽  
High Strength ◽  
Initial Crack ◽  
Full Scale ◽  
Velocity Curve ◽  
Gas Pipelines ◽  
Energy Prediction

The fracture arrest of high pressure gas pipelines is one of the keen subjects for application of high strength line pipes. To examine the arrestability of high strength line pipes against crack propagation, several full scale fracture propagation tests have been conducted. The fracture propagation tests of X100 or X120 under high pressure revealed that the existing models of arrest energy prediction failed to predict the arrest energies. By careful investigations of the test results, it is found that the failure in prediction is mainly due to the uncertainty of crack velocity curve prediction. On the other hand, accuracy of predicted gas decompression curve is relatively high even in the case of high pressure condition. Experimentally, the arrest energies have been determined by full-scale fracture propagation tests with increasing toughness arrangement. Different from actual pipeline, extremely low toughness pipe has been employed in crack initiation pipe with intention of getting steady state propagation. However, arrestability of pipe might be underestimated in the increasing toughness arrangement test as the initial crack velocity increases. Together with recalibrated crack velocity curve, Sumitomo model (HLP method with Sumitomo’s crack velocity curve) predicts that even toughness arrangement, which is the case of real pipelines, could arrest the propagating shear fracture in high pressure gas pipelines by X100.

Prediction of Ductile Fracture Propagation of High Strength Steels in Automotive Structures

2019 ◽  
Author(s):  
Kentaro Sato ◽  
Takayuki Futatsuka ◽  
Hideyuki Okada ◽  
Yasuhisa Egawa ◽  
Kenichiro Fukagawa ◽  
...  
Keyword(s):  
Ductile Fracture ◽  
Fracture Propagation ◽  
High Strength Steels ◽  
High Strength ◽  
Automotive Structures

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

scholarly journals Tribological Behavior of Laser Textured Hot Stamping Dies

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Andre Shihomatsu ◽  
Sergio Tonini Button ◽  
Iris Bento da Silva
Keyword(s):  
Surface Topography ◽  
High Pressures ◽  
Hot Stamping ◽  
High Strength Steels ◽  
High Strength ◽  
Experimental Tests ◽  
Textured Surface ◽  
Laser Texturing ◽  
Stamping Dies ◽  
Before And After

Hot stamping of high strength steels has been continuously developed in the automotive industry to improve mechanical properties and surface quality of stamped components. One of the main challenges faced by researchers and technicians is to improve stamping dies lifetime by reducing the wear caused by high pressures and temperatures present during the process. This paper analyzes the laser texturing of hot stamping dies and discusses how different surfaces textures influence the lubrication and wear mechanisms. To this purpose, experimental tests and numerical simulation were carried out to define the die region to be texturized and to characterize the textured surface topography before and after hot stamping tests with a 3D surface profilometer and scanning electron microscopy. Results showed that laser texturing influences the lubrication at the interface die-hot sheet and improves die lifetime. In this work, the best texture presented dimples with the highest diameter, depth, and spacing, with the surface topography and dimples morphology practically preserved after the hot stamping tests.

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