Accession Number : ADA019261

Title :   EFFECT OF SPECIMEN THICKNESS ON FATIGUE CRACK-GROWTH RATE IN 5NI-CR-MO-V STEEL - COMPARISON OF HEAT-TREATED AND STRESS-RELIEVED SPECIMENS.

Descriptive Note : Final rept. on Phase 1,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s) : SULLIVAN, A. M. ; Crooker, T. W.

Report Date : 09 DEC 1975

Pagination or Media Count : 17

Abstract : Ship structural design now incorporates the weight-saving advantage of high-strength alloys by reducing the thickness requirements of load-bearing members. For fail-safe applications of thin-section material (less than 0.50 in. (12.5mm) thick) in high-performance ship structures, quantitative information concerning the fatigue crack-growth rate (FCGR) in both ambient air and the marine environment is highly important. The paucity and diverse conclusions of presently available information concerning the effect of material thickness on FCGR provides little engineering guidance for the design of thin-section naval structures. This study of FCGR on a 5Ni-Cr-Mo-V steel tested in three thicknesses indicates that internal residual stresses may have a retardation effect on FCGR in this material. When tested after stress relief, although crack growth is accelerated, it is essentially the same for all thicknesses. (Author)

Descriptors :   *STEEL, *CRACK PROPAGATION, *HIGH STRENGTH ALLOYS, SHIP STRUCTURAL COMPONENTS, MARINE ATMOSPHERES, THICKNESS, NICKEL ALLOYS, RESIDUAL STRESS, MECHANICAL PROPERTIES, HEAT TREATMENT, FATIGUE(MECHANICS), REGRESSION ANALYSIS, HIGH STRENGTH ALLOYS, STRESS RELIEVING.

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE