The Fatigue and Toughness Properties of a C-Mn-Cb Plate Steel

Abstract

The fatigue and toughness properties of a C-Mn-Cb plate steel, described both by ASTM A633C and A737B, are presented and compared to the properties of A516-70. Production plate steels made by both conventional steelmaking techniques and low sulfur-calcium treatment are evaluated. The superiority of A633C over A516-70 in transition and upper shelf fracture toughness is demonstrated in both Charpy-V-notch and Dynamic Tear impact testing, as well as J-Integral fracture toughness at both a slow and fast loading rate. There was no substantial difference in fatigue behavior between the A633C and A516-70 steels, except that A633C was found more sensitive to inclusions, thus there was more of a pronounced improvement shown by using calcium treatment. The fatigue behavior was assessed using S-N axial fatigue testing, fatigue crack propagation testing and by determining the threshold for fatigue crack propagation. The residual stresses in A633C in the quenched and tempered condition influenced the fatigue crack propagation and near threshold behavior of this steel.