SEDL / STP / STP1130-EB / STP15522S

Crack-Arrest and Static Fracture Toughness Tests of a Ship Plate Steel

Underwood, JH
Research engineer, Benet Laboratories, Army Armament Research, Development and Engineering Center, Watervliet, NY

Burch, IA
Experimental officer and senior principal research scientist, Materials Research Laboratory, Defence Science and Technology Organisation, Melbourne,

Ritter, JC
Experimental officer and senior principal research scientist, Materials Research Laboratory, Defence Science and Technology Organisation, Melbourne,

Pages: 14    Published: Jan 1992

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Abstract

The recently standardized ASTM Test for Determining the Plane-Strain Crack Arrest Fracture Toughness K^Ia of Ferritic Steels (E 1221) was modified for use with BIS 690 steel, an Australian low-alloy, 700-MPa strength, quenched and tempered steel used for ship plate. Specimens of 50-mm thickness in longitudinal and transverse orientations were tested at -60°C with various depths of side groove. Specimen configurations somewhat outside the range of ASTM Test E 1221 were found to be useful for this steel and were suggested as modifications to the standard method. A different solution and expression for stress intensity factor were used to evaluate the tests and to develop a method for predicting the crack length at which a running crack will arrest. Good agreement was obtained between the observed and predicted crack lengths at arrest.

The wedge-loading arrangement of the crack-arrest test procedure was used for static fracture toughness tests. Procedures for static wedge-loading fracture toughness were proposed, particularly for comparisons with crack-arrest toughness test results obtained under similar test conditions. for the tests here, the static fracture toughness was more than twice the value of crack-arrest toughness.