Accession Number : AD0707711

Title :   DYNAMIC TEAR TEST INVESTIGATIONS OF THE FRACTURE TOUGHNESS OF THICK-SECTION STEEL.

Descriptive Note : Final summary rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Loss,F. J.

Report Date : 14 MAY 1970

Pagination or Media Count : 55

Abstract : The effect of mechanical constraint imposed by thick sections is examined in the framework of linear elastic fracture mechanics (LEFM) and other temperature-transition indices. Extrapolation of thin-section LEFM data to higher temperatures has raised the concern that thick-section steels, of shelf toughness and strength class similar to A533-B, will not exhibit a brittle-to-ductile transition with increasing temperature. Research programs relating to thick dynamic tear (DT) test studies and those relating to thick LEFM investigations have shown that unirradiated A533-B does exhibit a significant increase in toughness within a relatively narrow temperature region near the nil ductility transition (NDT) temperature. Size effects studies indicate that the effects of mechanical constraint associated with thick sections elevate the fracture transition--elastic (FTE) temperature (the temperature at which very large flaws remain dormant up to yield stress) for 12-in.-thick sections approximately 70F (39C) above the FTE temperature for thin sections, which in turn is 60F (33C) above the NDT temperature. (Author)

Descriptors :   (*STEEL, FRACTURE(MECHANICS)), TOUGHNESS, PRESSURE VESSELS, NUCLEAR REACTORS

Subject Categories : Metallurgy and Metallography
      Fission Reactor Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE