NOTCH BRITTLENESS AFTER PRESTRAINING.
BROWN UNIV PROVIDENCE R I
Pagination or Media Count:
Notched plates and bars prestrained in compression or extension, before or after notching, at 70F or 550F were tested to fracture in tension at -16F. It was found that a catastrophic reduction of ductility could be caused by small prestrains. Uniform longitudinal or transverse prestraining by as little as 0.05 at 70F reduced the initial ductility of notched bars by a factor of 4 or more. Hot prestraining was even more damaging the greatest drop in the ductility at -16F was caused by prestrains of only 0.025 at 550F. These tests indicate that the brittle behavior of mild steel structures results from some damaging prior history of straining. Accordingly the proper selection of steels should be based on their resistance to embrittlement by suitable straining rather than on their properties in the initial undamaged state. The presented testing methods offer a great control over the steel ductility. They would be useful both in steel assessment and in the investigations of the factors influencing the resistance of steel to fracture. Author
- Metallurgy and Metallography
- Structural Engineering and Building Technology