Application of Indirect Methods to the Evaluation of Ductile Fracture Toughness of a Quenched and Tempered Steel

The ductile fracture toughness of a quenched and tempered steel was measured according to ASTM E813-81 for the determination of J//I//c and ECO (energy for crack equal to 0) proposed by R. Ravez; (b) the equivalent energy method proposed by F. J. Witt; (c) J//5, i. e. , the J integral level applied when the load is equal to the 95% of the maximum load as proposed by J. H. Underwood; and (d) the correlation between K//I//c, yield strength and Charpy V impact energy proposed by J. M. Barsom, S. T. Rolfe and S. R. Novak and by R. H. Sailors and H. T. Corten. The equivalent energy method yields results that are dependent on the specimen geometry. The J//5 method yields better results when W equals 2B. The correlation between fracture toughness parameters, Charpy V impact energy and yield strength does not give a good accordance between calculated and experimental fracture toughness for the experimental steel.