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You searched on: Author: christopher mccowan Sorted by: date

Displaying records 1 to 10 of 65 records.
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1. NIST Room Temperature Low-Energy and High Energy Verification Specimens: Feasibility Study
Series: NIST Interagency/Internal Report (NISTIR)
Published: 10/21/2015
Authors: Enrico Lucon, Christopher N McCowan, Raymond L Santoyo
Abstract: The feasibility of certifying Charpy reference specimens (SRMs) for testing at room temperature (RT, 21 °C ± 1 °C) instead of -40 °C was demonstrated at NIST by performing 130 RT tests from nine low-energy and high-energy lots on the three master mac ...

Published: 7/19/2015
Authors: Enrico Lucon, Christopher N McCowan, Raymond L Santoyo
Abstract: NIST in Boulder Colorado investigated the correlations between impact test results obtained from standard, full-size Charpy specimens (CVN) and specimens with reduced thickness (sub-size Charpy specimens, SCVN) or reduced or scaled cross-section dime ...

3. Certified KLST Miniaturized Charpy Specimens for the Indirect Verification of Small-Scale Impact Machines
Published: 4/28/2015
Authors: Enrico Lucon, Christopher N McCowan, Raymond L Santoyo, Jolene D Splett
Abstract: Small specimen test techniques are becoming ever more popular as the need increases to characterize mechanical properties by use of the smallest possible amount of material, due to various restrictions on material availability, irradiation, testing s ...

4. Establishment of an International Scale for Instrumented Charpy Testing: comparison between NIST and LNE
Series: Technical Note (NIST TN)
Report Number: 1875
Published: 4/1/2015
Authors: Enrico Lucon, Christopher N McCowan, Raymond L Santoyo, Stephane Lefrancois
Abstract: As a contribution to the establishment of an international scale for instrumented Charpy testing, aimed at ensuring that impact forces are obtained more accurately, NIST and Laboratoire National de métrologie et d‰Essais (LNE, France) have partic ...

5. Impact Characterization of 4340 and T200 Steels by Means of Standard, Sub Size and Miniaturized Charpy Specimens
Series: Technical Note (NIST TN)
Report Number: 1858
Published: 2/10/2015
Authors: Enrico Lucon, Christopher N McCowan, Raymond L Santoyo
Abstract: In this investigation, we performed instrumented Charpy tests in order to characterize the impact properties of three steels, used by NIST for the production of Charpy reference specimens (4340 quenched and tempered with two energy levels, and T2 ...

6. Impact Characterization of Line Pipe Steels by Means of Standard, Sub-Size and Miniaturized Charpy Specimens
Series: Technical Note (NIST TN)
Report Number: 1865
Published: 2/10/2015
Authors: Enrico Lucon, Christopher N McCowan, Raymond L Santoyo
Abstract: Modern line pipe steels are characterized by a continuously increasing ratio between ductility and mechanical strength, which makes it difficult to interpret the results of conventional Charpy impact tests. For such tests, the extremely high abso ...

7. CTOA Testing of Pipeline Steels Using MDCB Specimens
Published: 9/1/2013
Authors: Robert L Amaro, Jeffrey W Sowards, Elizabeth S Drexler, Joseph David McColskey, Christopher N McCowan
Abstract: Crack tip opening angle (CTOA) is used to rank the relative resistance to crack extension of various pipeline steels. In general, the smaller the CTOA value, the lower the resistance to crack extension. It is unclear, however, whether CTOA is a mater ...

8. Modeling flat to slant fracture transition in CTOA specimens using the computational cell methodology
Published: 2/23/2013
Authors: Christopher N McCowan, Jacques Besson, Elizabeth S Drexler
Abstract: Macroscopicmode I ductile crack propagation in thin metallic sheets often starts in mode I as a flat triangle whose normal corresponds to the loading direction. After some limited extension, the crack becomes slanted and propagates under local mixed ...

9. Interpretation and significance of reverse chevron-shaped markings on fracture surfaces of API X100 pipeline steels
Published: 8/15/2012
Authors: Christopher N McCowan, Elizabeth S Drexler, Jeffrey W Sowards
Abstract: Fracture surfaces of X100 pipeline steels were examined with optical and electron microscopy following fracture testing. The fractures show chevron-like fracture patterns, but are distinctly different from classic chevron fracture. The chevron-li ...

10. Ductile-Fracture Resistance in X100 Pipeline Welds Measured with CTOA
Published: 12/1/2011
Authors: Elizabeth S Drexler, Philippe P. Darcis, Christopher N McCowan, Jeffrey W Sowards, Joseph David McColskey, Thomas A. (Thomas A.) Siewert
Abstract: A test for evaluation of resistance to ductile fracture (crack tip opening angle, CTOA) was found to reveal changes in crack propagation through the strain and strength gradients near weld joints in X100 pipeline steels. This test provides a long lig ...

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  • SP 250-XX: Calibration Services
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