SEDL / STP / STP833-EB / STP32565S

Effect of Section Size on Transition Temperature Behavior of Structural Steels

Landes, JD
Manager, Mechanics of Materials Research, and Senior Engineer, Westinghouse R&D Center, Pittsburgh, Pa.

McCabe, DE
Manager, Mechanics of Materials Research, and Senior Engineer, Westinghouse R&D Center, Pittsburgh, Pa.

Pages: 15    Published: Jan 1984

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Abstract

The transition temperature behavior of structural steels was evaluated using fracture mechanics specimens and elastic-plastic evaluation techniques. In the transition temperature region, the ductile tear and JR-curve behavior of structural steels was relatively independent of test temperature and specimen geometry effects. Consistent JR-curve development was interrupted by J^c instability events, however, and it is this property that showed high sensitivity to test temperature and constraint variations. The temperature at which the J^c instability toughness rises rapidly was dominated by specimen thickness but within this behavior was a subtle interaction with constraint variations due to ligament length variations.

Specimens of fixed proportionalities can be used with Weibull analysis and extremal statistics methodology to demonstrate why the transition temperature behavior of steels is specimen size dependent. A distribution of J^c cleavage instabilities on small specimens can be used to predict J^c instability distributions on larger specimens.