A Fractographic Analysis of the Relationships Between Fracture Toughness and Surface Topography in Ultrahigh-Strength Steels
Author | : CD. Beachem |
Publisher | : |
Total Pages | : 15 |
Release | : 1968 |
ISBN-10 | : OCLC:1251662636 |
ISBN-13 | : |
Rating | : 4/5 (36 Downloads) |
Book excerpt: Fracture surfaces of fatigue precracked, notched tension test specimens of experimental oil quenched and tempered (800 F)0.45C-Ni-Cr-Mo steels of different residual sulfur contents, and of two 18Ni maraging steels (250 and 300 grades) were investigated, using electron fractography, by a task group composed of various members of Subcommittee II on Fractography of ASTM Committee E-24 on Fracture Testing of Metals. Sulfur levels of 0.008, 0.016, 0.025, and 0.049 weight per cent in the 0.45C-Ni-Cr-Mo steels corresponded to fracture toughness values (K1c) of 65.3, 55.6, 51.0, and 42.8 ksi?in., respectively. The 250- and 300-grade maraging steels exhibited K1c values of 68 and 42 ksi?in., respectively. The investigation was carried out to determine whether the differences in fracture toughness could be related to changes in fracture surface topography.