The company, Harland and Wolff of Belfast, Northern Ireland, needed to build the ship quickly and at reasonable cost, which may have compromised quality, said co-author Timothy Foecke. That the shipyard was building two other vessels at the same time added to the difficulty of getting the millions of rivets needed, he added.
"Under the pressure to get these ships up, they ramped up the riveters, found materials from additional suppliers, and some was not of quality," said Foecke, a metallurgist at the U.S. government's National Institute of Standards and Technology who has been studying the Titanic for a decade.
The company denies book's conclusions.
More than 1,500 people died when the Titanic, advertised as an "unsinkable" luxury liner, struck an iceberg on its maiden voyage in 1912 and went down in the North Atlantic less than three hours later.
"The company knowingly purchased weaker rivets, but I think they did it not knowing they would be purchasing something substandard enough that when they hit an iceberg their ship would sink," said co-author Jennifer Hooper McCarty, who started researching the Titanic's rivets while working on her Ph.D. at Johns Hopkins University in 1999.
On The Early Show Saturday, Jeff Glor asked McCarty if she felt the company was using sub-par iron.
"Exactly," she responded. "A rivet works by holding two plates together on a ship. And, during the collision, pressure, or load on that plate would have caused the heads of the rivets to pop open. So, the theory really is that the sub-quality iron caused weak rivets, and therefore, the seams were weak, and opened up during the collision.
McCarty says it was "an engineering decision" to use the rivets they did, "and, considering the other safety factors on the ship, they felt it would be OK to do so. I mean, it was a one-in-a-million chance that all of these events would come together and cause this disaster. So, it's difficult to say that they could have known something like this would happen."
The company disputes the idea that inferior rivets were at fault. The theory has been around for years, but McCarty and Foecke's book, "What Really Sank the Titanic: New Forensic Discoveries," published last month, outlines their extensive research into the Harland and Wolff archives and surviving rivets from the Titanic.
"It's difficult for them to be able to counterpoint all of our arguments," McCarty remarked to Glor, "given that there's so much in the (company) archives that we've gone through."
McCarty spent two years in Britain studying the company's archives and works on the training and working conditions of shipyard workers. She and Foecke also studied engineering textbooks from the 1890s and early 1900s to learn more about shipbuilding practices and materials.
"I had the opportunity to study the metallurgy of several rivets," McCarty said. "It was a process of taking thousands of images of the inside of these rivets, finding out what the structure was like, doing chemical testing and computer modeling.
"Seeing the kind of levels we saw in different areas, in different parts of the ship led us to believe they would have ordered from different people," she said, adding this may have led to the weaker rivets.
The two metallurgists tested 48 rivets from the ship and found that slag concentrations were at 9 percent, when they should have been 2 to 3 percent. The slag is a byproduct of the smelting process.