Single Specimen Fracture Toughness Testing of Low Strength Steel Plate Using The Direct Current Electrical Potential Method

1984 ◽  
Vol 12 (5) ◽  
pp. 297 ◽  
Author(s):  
R Horstman ◽  
KA Peters ◽  
S Gebremedhin ◽  
RL Meltzer ◽  
M Bruce Vieth ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Direct Current ◽  
Steel Plate ◽  
Electrical Potential ◽  
Potential Method ◽  
Single Specimen ◽  
Fracture Toughness Testing ◽  
Toughness Testing ◽  
Low Strength

Standardization of SENT (or SE(T)) Fracture Toughness Measurement: Results of a Round Robin on a Draft Test Procedure

2016 ◽  
Author(s):  
Sanjay Tiku ◽  
Nick Pussegoda ◽  
Morvarid Ghovanlou ◽  
W. R. Tyson ◽  
Aaron Dinovitzer
Keyword(s):  
Fracture Toughness ◽  
Test Procedure ◽  
Potential Drop ◽  
Round Robin ◽  
Single Specimen ◽  
Test Program ◽  
Round Robin Test ◽  
Fracture Toughness Testing ◽  
Growth Measurement ◽  
Toughness Testing

Fracture toughness of steels is conventionally measured using bend specimens and provides a conservative estimate of toughness when the actual loading is in tension. There has been widespread interest in characterizing the toughness that occurs with reduced constraint to better reflect constraint conditions typical of a relatively shallow girth weld flaw. There is currently a standardized approach to measure fracture toughness in tension loaded specimens, however, it requires testing of multiple specimens to generate a resistance curve. Recent developments in fracture toughness testing and analysis of tension loaded specimens have led to publications by CANMET and Exxon Mobil Upstream Research Company toward development of a single-specimen procedure. As part of an initiative to enhance the state of the art in strain based design and assessment methods, with the intent of providing support for the standardization of appropriate weld testing methods, BMT under a Pipeline research Council International (PRCI) project has combined the two single-specimen approaches and developed a recommended practice for fracture toughness testing using single-edge-notched tension SENT (or SE(T)) samples with fixed grip loading. The procedure has been assessed by means of a round robin test program involving laboratories from around the world. Girth welds were fabricated and base metal, heat affected zone and weld center line specimens were prepared and sent to round robin participants. For the round robin program all the participants used a double clip gauge arrangement for direct CTOD measurement and electric potential drop measurement or unloading compliance method for crack growth measurement. In this paper, the results of the round robin test program including comparison of J and CTOD resistance curves will be presented and discussed.

Fracture Toughness Testing and its Implications to Engineering Fracture Mechanics Analysis of Energy Pipelines

2018 ◽  
Author(s):  
Sergio Limon ◽  
Peter Martin ◽  
Mike Barnum ◽  
Robert Pilarczyk
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Test Data ◽  
Fracture Mode ◽  
Fracture Process ◽  
Fracture Behavior ◽  
Fracture Initiation ◽  
Fracture Toughness Testing ◽  
Final Fracture ◽  
Toughness Testing

The fracture process of energy pipelines can be described in terms of fracture initiation, stable fracture propagation and final fracture or fracture arrest. Each of these stages, and the final fracture mode (leak or rupture), are directly impacted by the tendency towards brittle or ductile behavior that line pipe steels have the capacity to exhibit. Vintage and modern low carbon steels, such as those used to manufacture energy pipelines, exhibit a temperature-dependent transition from ductile-to-brittle behavior that affects the fracture behavior. There are numerous definitions of fracture toughness in common usage, depending on the stage of the fracture process and the behavior or fracture mode being evaluated. The most commonly used definitions in engineering fracture analysis of pipelines with cracks or long-seam weld defects are related to fracture initiation, stable propagation or final fracture. When choosing fracture toughness test data for use in engineering Fracture Mechanics-based assessments of energy pipelines, it is important to identify the stage of the fracture process and the expected fracture behavior in order to appropriately select test data that represent equivalent conditions. A mismatch between the physical fracture event being modeled and the chosen experimental fracture toughness data can result in unreliable predictions or overly conservative results. This paper presents a description of the physical fracture process, behavior and failure modes that pipelines commonly exhibit as they relate to fracture toughness testing, and their implications when evaluating cracks and cracks-like features in pipelines. Because pipeline operators, and practitioners of engineering Fracture Mechanics analyses, are often faced with the challenge of only having Charpy fracture toughness available, this paper also presents a review of the various correlations of Charpy toughness data to fracture toughness data expressed in terms of KIC or JIC. Considerations with the selection of an appropriate correlation for determining the failure pressure of pipelines in the presence of cracks and long-seam weld anomalies will be discussed.

Equipment for fracture toughness testing of specimen at low temperatures

1988 ◽  
Vol 20 (5) ◽  
pp. 698-702
Author(s):  
I. D. Abushenkov ◽  
A. I. Alekseev ◽  
V. Ya. Il'ichev ◽  
N. I. Mokryi ◽  
A. I. Telegon ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Low Temperatures ◽  
Fracture Toughness Testing ◽  
Toughness Testing
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