Wednesday, December 13, 2006

Steel and Knowing it All




Someone wrote:
>German vs. Japanese steel?...give us a break with this nationality stuff.......<
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Okay. Here's your break :-)

About 1868 a Prussian military officer witnessed a Japanese samurai use his sword to cut through the barrel of a musket without damaging the sword. He was not able to buy a copy of the sword but he was allowed to view a sword-maker at work and to purchase several tons of the ore he used. Back in Germany the ore was reduced to iron and the iron converted to steel. It proved to have remarkable properties of strength, toughness and hardenability, which was eventually attributed to traces of molybdenum in the original ore.

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We now have the ability to identify the composition of almost anything down to a fineness of so many parts per million. At that level of precision you'd think nature would have no secrets left. But there are some compounds that are lethal to humans in concentrations as low as parts per billion... and a virus is even smaller than that, when compared to the mass of the human body. When we insist we know everything there is to know about steel, engineering or whatever, we're actually defining the existing limits of what we know. Which is another way of saying we've still got a lot to learn.

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Do you weld? It's a useful skill, easy to learn. But it will teach you at first hand that no matter what it says on the spec sheet, not all steels are the same. That's because most utility-grade steels -- 'angle-iron.' ERW tubing and so forth -- tests only for the basic composition of iron & carbon. In recycling an oil tanker or old aircraft carrier most of the steel will return to the marketplace as basic SAE 1020 mild steel, which most of it is. But a lot of it isn't. I have made excellent leaf-type springs for flintlock rifles from rebar that came from the re-cycled hull of a Russian ice-breaker. The same is true for those 'national' steels someone mentioned. More than three quarters of all the steel ever made in America used ore from the Mesabi and Vermilion ranges in Minnesota. Old railroad men say they can tell the difference between a Mesabi rail and a Birmingham rail by its ring. I can't but maybe they can. And for a reason. Trace amounts of certain elements often result in steel having advantageous properties even though the tests show it is just plain old fashioned garden variety mild steel. Strange but true.

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So what's the point?

Mebbe that we should give folks the benefit of the doubt, even when they say something that appears to be nonsense, such as one nation’s steel being superior to that from another country, or knowing someone who can walk on water. (Come to think of it... :-)

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Then Dan wrote:

Interesting story. What would also be interesting is to the know the origins of the ore, since Japan is notorious for its lack of iron ore. They invaded several countries toward the end of the 19th Century and into the beginnings of the last century in search of iron ore deposits for their steel industry. One of those countries produces Hyundais if that is any help. Another is famous for its woks.


Well.... as a matter of fact, in 1868 none of those things had happened as yet. But I can appreciate the question, especially since Japan was making superior steel blades as early as 900 AD. The answer is quite simple. Look up ‘bog iron.’ This form of biologically concentrated iron was common in the marshes and streams on the three southern-most Japanese islands with some deposits large enough to support commercial mining operations (see the Gunma iron mine north of Tokyo) although not on a scale sufficient to support the level of industrialization desired by Emperor Meji.

-Bob Hoover
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