Following the presentation of a case study in the MOOC of EDX Tenaris University, I have learned the problems the designers had had by the Titanic ship, with the choice of materials for the construction of the metal plates that supported the structure of the ship and rivets of poor quality.
Apparently, the cold water of the North Atlantic, about 35 degrees Fahrenheit or 2.7 degrees Celsius even less, transformed the molecular structure of steel plates, instead of ductile became brittle. This meant that the first crash of the ship with the iceberg, the plates did not bend and the rivets were fractured, allowing the entry of water very quickly.
The problem was because of that the steel chosen had a high content of sulfur and phosphorus, besides their relationship with manganese was very high. The crystal structure of steel from the Titanic became very brittle at low temperatures in the North Atlantic. The property which measures the relation between brittle and ductile is toughness.
Today, researchers have learned a lot from this and other failures such as the Liberty series freighters. Steels have been greatly improved and they can withstand the low temperatures like austenitic stainless steel 316 L. One of its many uses is to contain the liquid helium at temperatures of -269 degrees Celsius. Besides, the passage of austenite to martensite is more difficult in these types of steel, reducing and often tempering is needed, especially for watch cases. So it is a good choice to use steel 316 L for diver watch cases.
Perhaps the only problem I see with this type of steel is the nickel content of up to 14%. While Nickel decreases corrosion in steel and allows better machining, the percentage so high in so sensitized population to allergens factors, it can cause sensitization problems like eczema on the skin or even in remote areas only for exceeding the threshold of nickel in blood, as may be the mouth or throat.