Titanic Fracture of Steel R. Winston Revie Emeritus Scientist CanmetMATERIALS 555 Booth Street Ottawa

Titanic Timeline March 31, 1909Keel laid May 31, 1911Launched April 2 – 4, 1912Sea trials April 10, 1912Departed Southampton April 14, 1912Struck iceberg Sept. 1, 1985Robert Ballard found Titanic July 24, 1991Samples delivered to CANMET

Titanic Riveted construction – HullSteel – RivetsCast iron Seawater temperature−2°C At bottom of North Atlantic for 79 years

History In North Atlantic during World War II, several ships broke in two, leading to discovery of the transition temperature of steel Fractures at 4°C originated at stress concentrations (sharp corners, defects) and propagated the entire girth of the ship. S. S. Schenectady January 1943 near Portland, Oregon

Toughness ‘Tough’ and ‘brittle’ are opposites Resistance of a material to shock, or impact, loading

Measuring Toughness Toughness of a material is measured by testing in impact, typically the Charpy test, developed by French scientist, Georges Charpy, in 1905.

Temperature Matters

Important Variables Steel Temperature Design – Stress Concentrations Modern high-strength, high- toughness steel

Microstructure of Hull Plate

References R. J. Brigham and Y. A. Lafrenière, “Titanic Specimens,” CANMET Metals Technology Laboratories, Report Number 92-32(TR), 1992 Katherine Felkins, H. P. Leighly, Jr., and A. Jankovic, “The Royal Mail Ship Titanic: Did a Metallurgical Failure Cause a Night to Remember?” Journal of Metals 50(1), (1998)