|Speaker:||Tim Foecke, National Institute of Standards and Technology|
|Topic:||“Forensic Metallurgy of the RMS Titanic”|
President Agger called the 2095th meeting to order at 8:20 p.m. on November 6, 1998. The Recording Secretary read the minutes of the 2094th meeting and they were approved.
The speaker for the 2095th meeting was Tim Foecke of the National Institute of Standards and Technology. The title of his presentation was, “Forensic Metallurgy of the RMS Titanic.”
What sank the Royal Mail Ship (RMS) Titanic? At that time, it was the largest moving man-made object ever built. She was 882 feet long, made up of 3,000 one-inch thick mild steel plates held together by three million one-inch diameter rivets. It took 11,000 laborers to build her in Belfast, Ireland.
Since that fateful night in April 1912, there has been incredibly sustained interest in determining what really happened to the “unsinkable” Titanic. She was found in 1985 under 12,000 feet of water, where the pressure was 6,000 psi. Surprisingly, she was found to be broken into two pieces, 3/4 mile apart and facing in opposite directions. This confirmed the scattered testimony of some passengers that she broke in two at the surface. However, it ran contrary to every account of the disaster given by surviving ship's officers. This new finding fueled even more speculation as to how and why Titanic sank as she did. Evidence currently points away from the theory that the brittle steel hull allowed the ship to shatter on impact with the iceberg. Rather, it appears that a very unlucky set of circumstances involving collision dynamics and riveting may have led to the most famous maritime disaster in history.
With physical access to the ship, it became possible to conduct a systematic and methodical scientific and forensic analysis of the details of the sinking. A panel of experts was assembled to perform the first detailed scientific investigation of the wreck. Mr. Foecke led us through the findings of the panel. He also passed around the audience a number of actual rivets recovered from the Titanic.
The results of laboratory analyses of metallurgical samples of hull plate and rivets recovered from the Titanic showed that although the steel used to construct the hull was of low toughness at ice water temperatures; it was adequate in strength. It is possible that brittle steel contributed to the damage at the bow due to the impact with the iceberg, but is much more likely the brittle steel was a factor in the breakup of the ship at the surface before it plunged into the sea. However, the microstructure of the rivets produced by the assembly process during ship construction may have caused the slag stringers to be adversely oriented perpendicular to the strong tensile axis. This may have been a direct contributor to the type and distribution of the observed damage to the hull.
Ironically, the damaged bow area of the hull that struck the iceberg is buried in 50 feet of mud. However, sub-surface sonar imaging did not show a big hole, rather six separate plate separations spanning six compartments of the ship. Thus, it is likely that Titanic did not flood like an ice-cube tray filling with water spilling from one compartment to another. Rather, she more likely slowly flooded through the hull plate separations in each of the first six compartments. Mr. Foecke concluded that at the time, the design of Titanic was appropriate and no metallurgical mistakes were made in her construction. She sank due to bad luck and bad operation by hitting an iceberg at 22 knots.
This great ship still lies where it came to rest on the bottom of the sea almost 90 years ago. Adding to her already enormous mystique is the fact that the exposed superstructure, of which we have seen so many pictures, will completely collapse within the next twenty years. Further, the entire ship will convert from iron oxide to an unrecognizable pile of iron silicate within the next 70 to 80 years and bring a modicum of finality to her story.
Mr. Foecke closed his presentation and kindly answered questions from the floor. President Agger thereupon thanked Mr. Foecke for the society, announced the next meeting and made the usual parking announcement. She then adjourned the 2095th meeting to the Social Hour at 9:50 p.m.
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