An Updated Fracture Resistance Dataset of Pipeline Ductile Fracture Propagation Based on High Speed DWTT Tests

2014 ◽  
Author(s):  
Da-Ming Duan ◽  
James Ferguson ◽  
Joe Zhou ◽  
Mohammed Uddin ◽  
Do-Jun Shim
Keyword(s):  
Fracture Toughness ◽  
Steady State ◽  
Ductile Fracture ◽  
High Speed ◽  
Fracture Propagation ◽  
Gas Pipeline ◽  
Charpy Specimen ◽  
Low Grade ◽  
Speed Dependence ◽  
Fracture Control

One of the major research topics in the area of gas pipeline fracture control is the suitability of using Charpy energy for ductile fracture control for modern and/or high strength line pipes. A common understanding is that, for pipe body crack self-arresting, the deviation of the actual required Charpy energy from those predicted using the traditional procedure of Battelle Two-Curve Method (TCM) is getting larger with higher strength pipes. DWTT is being paid more attention to because of its larger and full thickness specimen that can better capture the fracture process than a Charpy specimen does. Previous work at TransCanada indicated that various fracture speeds can be achieved in DWTT specimens and it is the steady-state fracture speed that is representative to the actual fracture propagation in a gas pipeline. It has also been found that the steady-state fracture toughness, in terms of either fracture energy or CTOA, is fracture speed dependent with lower fracture toughness for higher fracture speeds. Previous analysis also indicated by considering the speed dependent toughness, better predictions can be obtained for both self-arresting fracture toughness requirement and the fracture propagation speed. Previous DWTT fracture toughness data published by the authors exhibited a strong speed dependence and it was demonstrated that if the actual speed dependence is plugged into the modified TCM, both the fracture toughness and fracture speed would be over predicted. The assumption was that the original TCM was calibrated using pipe fracture data that also had speed dependent fracture toughness but the speed dependence was less strong than those for the modern pipes. This paper presents an updated DWTT fracture dataset that expands the previously published data by adding high speed DWTT test results of modern line pipe steels with a range of grades X70-X100 and three old vintage pipe materials that is representative to the pipes that were used for the original TCM testing and calibration. The toughness data for the low grade pipes also shows speed dependence which purports the previous assumption.

Effect of Fracture Speed on Ductile Fracture Resistance: Part 2—Results and Application

2010 ◽  
Author(s):  
Da-Ming Duan ◽  
Joe Zhou ◽  
Do-Jun Shim ◽  
Gery Wilkowski
Keyword(s):  
Fracture Toughness ◽  
Steady State ◽  
Ductile Fracture ◽  
High Speed ◽  
Material Selection ◽  
Basic Material ◽  
Pipe Material ◽  
High Grade ◽  
Control Plan ◽  
Material Fracture

One of the many aspects of natural gas pipeline design and material selection is the consideration of propagation and arrest of high-speed axial ductile fracture in the line pipes. Understanding the material ductile fracture behavior is essential for establishing an integrated fracture control plan. This is particularly important for pipelines of high design pressures utilizing large-diameter and high-grade line pipes. The procedure of Battelle Two-Curve Method (TCM) has been most commonly used in ductile fracture analysis in the prediction of fracture speed and minimum arrest toughness for axially running cracks. In the past decades, discussions and research have been in that the TCM approach, among with others, could not accurately predict either fracture speed or minimum arrest fracture toughness for high-grade pipes, and with pipe grade increasing the prediction errors are getting larger. Recent research work at TransCanada indicates that for a better prediction of pipeline ductile fracture, understanding the basic material mechanical behavior and its fundamental fracture mechanism is essential. One of the important findings of the work is that pipe material fracture toughness is not a constant as being commonly treated, rather the fracture toughness, in terms of both steady-state CTOA and steady-state DWTT fracture energy is fracture speed dependent, being decreasing with increasing fracture speed. Corresponding modifications have been made to the traditional TCM by introducing speed-dependent fracture toughness. The improved model gives much better predictions in both fracture speed and toughness for high grade pipes. This paper presents recent work at TransCanada, together with its industry partner Engineering Mechanics Corporation of Columbus (EMCC), on high-speed pipe-material fracture testing technique (using the modified back-slot DWTT specimen) and high-grade material testing data. The test data supports the predictions of early published work on speed-dependent fracture toughness. The fracture speeds obtained from the modified back-slot DWTT specimens were very close to actual full-scale pipeline ductile fracture speeds and this in turn enhanced the applicability of the modified TCM model.

Ductile Fracture Control for High Strength Steel Pipelines

2006 ◽  
Author(s):  
Andrea Fonzo ◽  
Andrea Meleddu ◽  
Giuseppe Demofonti ◽  
Michele Tavassi ◽  
Brian Rothwell
Keyword(s):  
Ductile Fracture ◽  
High Strength Steel ◽  
Driving Force ◽  
Empirical Relationship ◽  
Fracture Propagation ◽  
High Strength ◽  
Operating Conditions ◽  
Resistance Force ◽  
Fracture Control ◽  
Material Fracture

The determination of the toughness values required for arresting ductile fracture propagation has been historically based on the use of models whose resulting predictions can be very unreliable when applied to new high strength linepipe materials (≥X100) and/or different operating conditions. In addition, for the modern high strength steels a methodology for determining the material fracture resistance for arresting running shear fracture starting from laboratory data is still lacking. The work here presented (developed within a PRCI sponsored project) deals with the use of CSM’s proprietary PICPRO® Finite Element code to develop methodologies for ductile fracture propagation control in high grade steel pipes. The relationships providing the maximum crack driving force which can be experienced in a pipe operated at known conditions have been determined, for different types of gas. On the other side, an empirical relationship has been found to correlate the critical Crack Tip Opening Angle (CTOA) determined by laboratory testing, to the critical CTOA on pipe (which represents the material fracture propagation resistance) with the aid of devoted simulations of past full-scale burst tests. By comparing Driving Force and Resistance Force, ductile fracture control for high strength steel pipelines can be achieved.

Ductile Fracture Resistance Measurements in High Grade Steels

2006 ◽  
Author(s):  
L. N. Pussegoda ◽  
A. Fredj ◽  
A. Fonzo ◽  
G. Demofonti ◽  
G. Mannucci ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Steady State ◽  
Ductile Fracture ◽  
Fracture Resistance ◽  
Process Zone ◽  
Fracture Propagation ◽  
Crack Tip ◽  
Opening Angle ◽  
Displacement Curve ◽  
High Grade

Recent developments in ductile fracture resistance measures in high grade steels in the pipeline industry include the crack tip opening angle (CTOA) and “steady state” fracture propagation energy, using 3-point bend specimens. The CTOA has been found to be a function of specimen ligament size. With the availability of instrumented hammers, it became possible to resolve propagation energy using the load-displacement curve using a single specimen. This paper focuses on refining the steady state fracture propagation energy, using back-slotted Drop Weight Tear Test (DWTT) specimens. The study included numerical simulation of the dynamic response of back-slotted specimens. The significance of the back-slot in altering the stress/strain field ahead of the propagation crack is discussed. The numerical simulation was also used to determine the strain rate in the “process zone” of the crack tip during steady state fracture propagation.

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.

Ductile Fracture Resistance Modeling Approach in Two High Grade Steels

2006 ◽  
Author(s):  
L. N. Pussegoda ◽  
A. Fredj ◽  
A. Dinovitzer ◽  
D. Horsley ◽  
D. Carlson
Keyword(s):  
Steady State ◽  
Crack Propagation ◽  
Ductile Fracture ◽  
Fracture Resistance ◽  
Fracture Propagation ◽  
Tension Test ◽  
Model Parameters ◽  
High Grade ◽  
Damage Mechanisms ◽  
Point Bend

Recent developments in ductile fracture resistance measures in high grade steels in the pipeline industry include the crack tip opening angle (CTOA) and “steady state” fracture propagation energy, using 3-point bend specimens. The CTOA has been found to be a function of specimen ligament size. Alternatives would be “steady state” fracture propagation energy, critical fracture strain and adoption of damage mechanisms. This paper focuses on modeling approaches for crack propagation using damage mechanisms. The tension test is used to “calibrate” the damage model parameters and applied to the crack propagation in a 3-point bend specimen in candidate high grade steels. The effects of using parameters developed from tension test and extending to a 3-point bend crack propagation scenario is discussed.

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.

COPPER ALLOY No. C94300

Alloy Digest ◽  
1984 ◽  
Vol 33 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Corrosion Resistance ◽  
Copper Alloy ◽  
High Speed ◽  
Heat Treating ◽  
Lead Alloy ◽  
Good Resistance ◽  
Tin Bronze ◽  
Strength Medium

Abstract Copper Alloy No. C94300 is a cast copper-tin-lead alloy (bronze). It is characterized by low hardness and strength, medium ductility, excellent machinability and good resistance to corrosion. Commercial names formerly used (but not recommended) are (1) Ingot No. 322, (2) Soft Bronze, (3) High-Leaded Tin Bronze and (4) 70-5-25. This alloy is recommended highly for high-speed bearings at light loads. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Cu-470. Producer or source: Copper alloy foundries.

CYCLOPS BHT

Alloy Digest ◽  
1965 ◽  
Vol 14 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Elevated Temperature ◽  
High Speed ◽  
High Speed Steel ◽  
High Strength ◽  
Heat Treating ◽  
High Load ◽  
Structural Components ◽  
Temperature Performance

Abstract Cyclops BHT is a low-alloy martensitic high-speed steel of the molybdenum type recommended for high strength, high load structural components designed for elevated temperature service. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-173. Producer or source: Cyclops Corporation.

ELECTRITE COBALT

Alloy Digest ◽  
1960 ◽  
Vol 9 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Physical Properties ◽  
High Speed ◽  
Cutting Tools ◽  
High Speed Steel ◽  
Heat Treating ◽  
Heavy Duty ◽  
Steel Company

Abstract ELECTRITE COBALT is a 5% cobalt type high-speed steel recommended for heavy duty cutting tools. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on forming, heat treating, and machining. Filing Code: TS-89. Producer or source: Latrobe Steel Company.

Sign in / Sign up

Export Citation Format

Share Document