SEDL / STP / STP945-EB / STP23234S

High-Temperature Crack-Arrest Toughness Measurements Using Compact Specimens

Rosenfield, AR
Research leader, master research technician, and senior research scientist, Battelle Memorial Institute, Columbus, OH

Mincer, PN
Research leader, master research technician, and senior research scientist, Battelle Memorial Institute, Columbus, OH

Marschall, CW
Research leader, master research technician, and senior research scientist, Battelle Memorial Institute, Columbus, OH

Pages: 13    Published: Jan 1988

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Abstract

The ASTM Crack-Arrest Test, which is under development, is generally limited to providing data up to 20 to 40°C above the ductile-to-brittle transition temperature (expressed as RT^NDT in the ASME Boiler and Pressure Vessel Code). For this test, the geometry is a wedgeloaded compact specimen containing a brittle weld starting notch, which appears incapable of reliably generating a rapid crack above the stated temperature range.

Two alternatives have been used for obtaining data at higher temperatures: very large specimens combined with soft loading systems and modified compact specimens. This paper describes compact-specimen modifications which have extended the successful temperature range to the onset of the Charpy upper shelf, the highest relative temperature reached being RT^NDT + 100°C.

Specific modifications utilized are: a high-strength steel crack-starter section (duplex specimen), a low-friction loading arrangement (inverted split pins), and contoured side grooves. The high-temperature data generated using these modifications compare favorably with largespecimen results.