Accession Number : ADA198132

Title :   Analysis of Ductile-Brittle Transition Temperatures for Controlled-Rolled, Microalloyed, C-Mn Based Steels.

Descriptive Note : Rept. for Dec 86-Dec 87,

Corporate Author : DAVID TAYLOR RESEARCH CENTER BETHESDA MD SHIP MATERIALS ENGINEERING DEPT

Personal Author(s) : Armstrong, R W ; Link, L R ; Speich, G R

PDF Url : ADA198132

Report Date : May 1988

Pagination or Media Count : 25

Abstract : Charpy V-notch ductile-brittle transition temperatures reported for a conventional carbon manganese steel and for several controlled-rolled microalloyed steels are compared with transition temperatures computed on a dislocation model basis. The computed transition temperature, Tc, is specified by equating the tensile cleavage fracture stress and the effective yield stress at the Charpy V-notch. Increased friction stress resistances to dislocation movement provided by solutes, precipitates, and other dislocations raise the yield stress and, thereby, increase Tc. A residual dislocation based friction stress resistance occurs within untransformed ferrite grains (that is, the ferrite present at the rolling temperature) when finish rolling is done in the austenite-ferrite region. Grain size refinement normally lowers Tc because the cleavage stress is increased to a greater extent than is the yield stress. Keywords: Ductile-brittle transition temperature, C-Mn steel, Carbide plate effects. (jes)

Descriptors :   *MANGANESE ALLOYS, *STEEL, CARBON STEELS, CLEAVAGE, DISLOCATIONS, DUCTILE BRITTLE TRANSITION, FERRITES, FRACTURE(MECHANICS), FRICTION, GRAIN SIZE, GRAIN STRUCTURES(METALLURGY), MODELS, PRECIPITATES, REFINING, RESISTANCE, ROLL, STRESSES, TEMPERATURE, TENSILE STRESS, TRANSITION TEMPERATURE, YIELD

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE