Which is better, iron or gold?

To Croesus, King of Lydia, on being shown his golden treasures, Solon said: “If another comes who hath better iron than you, he will take away your gold.”

Croesus on the pyre*

*image shown depicts King Croesus, unlikely to show Solon.

King Croesus introduces gold coinage (adopted by the Persians after they defeated him) although his coins used a gold-silver alloy (electrum) based on the composition of the alluvial deposits. When he asked the Delphic oracle of Amphiarus if he should wage a campaign against Cyrus the Great of Persia or seek an alliance, the Delphic advice was that if Croesus attacked the Persians, he would destroy a great empire.

Sources

Herodotus, The History of Herodotus, Translated by George Rawlinson

http://classics.mit.edu/Herodotus/history.mb.txt

http://www.thelatinlibrary.com/historians/herod/herodotus2.html

http://www.bartleby.com/344/370.html

Making a welded Damascus Knife

John Neeman Tools have posted a beautiful video of manufacturing a welded Damascus patterned knife.

5 layers of 3 different steels were forge-welded, folded, and forged. With each step being repeated 8 times. This produces a patterned with 320 layers. Finally twisting and forging the steel produces a more complex pattern.

Just checking the number of layers, I get their total to be different. My calculation of the number of layers is 5 × 2⁸ = 1280, that is 4 times more than claimed (320 layers should be the result of folding 6 times (6 folds 5 × 2⁶).

With 1280 folds, if we assume the thickness of the knife is 2 mm, that means each layer is 1.6 μm, 320 folds would be 6 μm layers. These are both lower than what can be resolved using the naked eye. It’s very close to the wavelength of visble light — if the metal were folded one more time, or the final thickness of the knife is less than 1 mm you would be there.

Most expensive Iron?

I went to the pharmacy today, the price of Iron there is pretty expensive.

Expensive Iron, 5.2 p per 14 mg.

5.2 pence per 14 mg tablet. That means the price per kg is £371,000 (371 thousand pounds), or 3.7 million pounds per tonne (3.7 M£/tonne).

This is amazing, the usual price of steel is more like 600 pounds per tonne, and around 1.5 trillion tonnes (1,510,222,000 tonnes) (1.5 Gigatonnes) of steel are produced annually. It seems like the steel industry should be selling this steel for 1000 times more. That would be a total of £5.6 &times 10¹⁵ or 5.6 P£ or 5.6 petapounds (I don’t know the financial term £5.6 million billion or 5.6 thousand trillion or 105 times world GDP).

Compared to the human body, the average amount of iron is about 3.5 g per person. That means we need 250 of these tablets to replace the iron in our body, at a cost of 13 pounds.

Future of steel production?

http://web.mit.edu/newsoffice/2013/steel-without-greenhouse-gas-emissions-0508.html

Details of a new process have been revealed, for alloying electrochemical production of iron, either for making iron (and oxygen!) on the moon or making electrolytic iron (and oxygen) on earth. The original process was developed for release of oxygen from moon rocks, using iridium metal electrodes. The new process uses chromium-iron electrodes.

The process has the potential to further reduce the carbon dioxide produced during steelmaking, when combined with electricity production from ‘carbon-dioxide neutral’ source.

Superbainite

Structure of superbainite. Inset is a same-scale image of a carbon nanotube. [1]

According to archaeologists, the Iron Age began in 1300 BC and lasted for around two millennia. Today, steels (alloys of iron and carbon) comprise 95% of global metal consumption and this trend shows no sign of declining.

Glancing at the media, however, one would be forgiven for assuming that steel is now a has-been. We are bombarded with stories of novel materials: carbon nanotubes, metallic glasses, graphene, carbon fibre, nickel superalloys. . . all of which are “stronger than steel”.

“Now we can construct space elevators!” claim the articles. “Let’s build a climbing frame to the moon! We’ll use this stuff to make everything!”

The observant among us, however, will note that most cars, trains and buildings still don’t feature superalloys, metallic glass or magic nanotubes. Neither are they invisible; nor do they fly; nor do they do any of the other things that journalists tend to ‘predict’.

Instead, steels somehow remain the best — and cheapest — materials for the job. Also, they are stronger than steel. This is because ‘steel’ is a vague construct used by sensationalists, with an unspecified strength guaranteed to be less than that of a novel material. Metallurgists rarely refer to ‘steel’, just as the Inuit have fifty words for snow, not one of which is ‘snow’.