Pickens writes "Metallurgists studying the hulk of the Titanic argue that the liner went down fast after hitting an iceberg because the ship's builder used substandard rivets that popped their heads and let tons of icy seawater rush in. They say that better rivets would have probably kept the Titanic afloat long enough for rescuers to have arrived, saving hundreds of lives. The team collected clues from 48 Titanic rivets and found many riddled with high concentrations of slag, a glassy residue of smelting that can make iron brittle. To test whether this extra slag weakened the rivets, scientists commissioned a blacksmith to make rivets to the same specifications as those used to join steel plates in the hull of the Titanic. When the plates were bent in the laboratory, the rivet heads popped off at loads of about 4,000 kg. With the right slag content they should have held up to about 9,000 kg. Even a few failures because of flawed metal would have been sufficient to unzip entire seams, because as faulty rivets popped, more stress would have been placed on the good ones, causing them to break in turn. The shipbuilder, which is still in existence, denies it all."