ISSN: 1945-7553
CODEN: JTEVAB
Page Count: 11

Evaluation of Published Data on Ductile Initiation Fracture Toughness of Low-Alloy Structural Steels

Ebrahimi, F
University of Florida, Gainesville, FL

Ali, JA
University of Florida, Gainesville, FL

(Received 22 December 1986; accepted 21 August 1987)

Abstract

Published data on ductile initiation fracture toughness, namely J-integral (J_i) and crack tip opening displacement (δ_i), of high-strength low-alloy steels with 275 MPa (40 ksi) minimum yield strength have been compiled along with material and testing parameters. Yield strength (σ_y) has been chosen as the main parameter for evaluating the compiled data. The compiled J_i and δ_i data showed a large range of variation at a given strength level. In an attempt to identify the testing parameters that contribute to this variation, the compiled data have been classified into four categories: (1) valid-standard, (2) valid-nonstandard, (3) invalid-standard, and (4) invalid-nonstandard. The critical review of sorted data has revealed that (1) microstructure, (2) testing method, and (3) validity contribute to both the scatter and the behavior of J_i values as a function of yield strength. The differences observed in the behavior of various sets of data are discussed considering the physical process of ductile crack initiation at the crack tip. The correlation between J_i and δ_i was investigated using linear regression analysis. The slope of the J_i/σ_y versus δ_i plot was found to be in the range 1.7 to 2.0.

Keywords:
J-integral, crack-opening displacement, high-strength low-alloy steel, fracture toughness, ductile crack initiation, data compilation

Paper ID: JTE11153J
DOI: 10.1520/JTE11153J
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