About old iron

Relic hunters and detectorist in general can learn a lot about the old iron artifacts they find by observing them closely. A good example of this is seen in the railroad spikes I collected from the late "Orange Belt Railway" which went out of business around 1900. Below are two spikes, one made from TRUE wrought Iron and one made from carbon steel. The two started out the same size but rusting of the carbon steel spike has reduced its size and weight by a third. The TRUE wrought iron spike is partially protected from corrosion by impurities in the metal, mainly silica which was from the ore TRUE wrought iron was made from. The corroded surface of the wrought iron spike has a fiberous appearence caused by the silica in strings or layers when the iron is hammered (wrought). The manufacture of wrought iron ceased abruptly in the late 1800s after the introduction of the Bessemer Converter which made it possible to make steel, stronger than the old wrought iron, and much cheaper simply by blowing air through the melted steel to remove impurities. The new steel which was known as carbon steel contained very little silica and therefore rusted rapidly. This became a problem for the railroad industry. Rails rusted away. Spikes lost their heads and came loose and boilers corroded through. For a time silicon was added back to the carbon steel and sold as 'wrought iron'. It was inferior to the true wrought iron in corrosion properties because the silica was in lumps rather than as fibers. Finally, by adding copper and some other trace metals to the steel much of its corrosion resistance was restored. Finding artifacts with this fiberous appearence almost assures they were 19th century or earlier. The corrosion resistance of true wrought iron is demonstrated by a chain suspension bridge in France that has been in use since the middle ages. Also shown is a sampling of the iron artifacts from the Orange Belt railway and the Coast Line which operated the line up until 1945. The artifacts were cleaned by electrolysis.   



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http://www.thunting.com/smf/index.php/topic,35801.msg218230.html#msg218230

Thanks for the information. I learned something today!

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http://www.thunting.com/smf/index.php/topic,35801.msg218276.html#msg218276

Very interesting. Didn't know that. I used to live near a Bessemer converter that was in use into the early 60s. When they blew that baby off you could see red sky from 10 miles away. Tore the last one out and put in a electric scrap melter. That was sort of neat, just knocked the daylights out of the local electric grid with flickering lights when the electrodes hit the cold steel .  I worked in an open hearth, OH#4, and a pour was really cool, well er actually... HOT! Still not as neat as the Bessemer..
Worked on the RR also and will have to go check out my date nails

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http://www.thunting.com/smf/index.php/topic,35801.msg226120.html#msg226120

Date nails are nails with a 2 digit date stamped into the nail-head.  They are used to date railroad ties, wooden trestles, etc so that workers can know when the tie was laid

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BA

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http://www.thunting.com/smf/index.php/topic,35801.msg226221.html#msg226221

As usual, my wife found her first date nail before I managed to find mine.  There fun to find but then most things are. 

BA

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http://www.thunting.com/smf/index.php/topic,35801.msg226458.html#msg226458