- Nov 20, 2007
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There's only 32 years between the two and Titanic is currently falling apart eaten by iron-hungry bacterias...
This depends on how it was sank. If I remember correctly, the Johnston got into one hell of a fight during the Battle of Samar and was later sunk by the sheer amount of shell hits, she had taken. So, most of the ship was flooded when she sank and only very few compartments with air trapped inside had suffered damage during the sinking.Its impressive that it wasn't more damaged by the four mile descent to the ocean floor.
We have a German industry norm that specifies what is steel and what is not, DIN EN 10020. Important for the definition is the 2% limit for carbon. If less than 2%, its steel. If more than 2%, its wrought iron (UNLESS: Its a certain historic type of chrome steel - this is still called steel, despite violating the scientific limit).I'm not sure quite what the metallurgical difference is between "iron" and "steel" in shipbuilding contexts, but in general, the types of alloys that get called "iron" vs "steel" are not very consistent. Cast iron has a very high carbon content, while wrought iron is very low carbon. About the only hard and fast rule that I can figure out is that pure iron is always called iron, other than that the difference between what gets called iron and what gets called steel seems more to have to do with the degree of control over composition afforded by the manufacturing process than with the composition itself.
"Gusseisen" is equivalent to English "cast iron", not "wrought iron", which is "Schmiedeeisen".
The problem with the definition "steel is anything below 2% iron" is that wrought iron falls in that category, but is generally not considered steel, and pure elemental iron has 0% carbon by definition, but is not considered steel (otherwise the element would be called steel, not iron).
The definition specifies, that it has to be an alloy which is mostly made of iron, with less than 2% carbon. Wrought iron is actually a type of steel, even if the historic name contains iron. The forging reduces the amount of slag in the sponge iron.