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Author Topic: What is "Stronger than Steel"?  (Read 21080 times)

Offline CliffordK

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What is "Stronger than Steel"?
« on: 10/06/2013 20:42:49 »
Every once in a while one hears of a new super-material.  Stronger & lighter than steel.

So, what exactly is "stronger than steel?

Steel, of course, comes in a variety of alloys from your typical "mild steel" to exceptionally strong tool steel, to somewhat brittle high speed steel.  And, of course, various stainless steel alloys.

I have some 50 year old pieces of farm equipment.  And, anything that isn't steel has sure taken a beating from weather checking of tires big enough to stick a finger in to huge cracks in the steering wheel. 

Airplanes, of course, have tremendous issues with metal fatigue.  Typically aluminum in the aircraft industry, but steel can also experience fatigue in some situations.

Often in use, while aluminum is lighter than steel, some of it is made up with more bulk  In some situations, bulk can lead to additional rigidity, but the weight savings is not always as high as one might expect.

There is a lot of talk about carbon fiber.  But, it might better be considered a fiber/resin composite.  I presume, however, it can fail under many of the same stresses that cause fiberglass to fail.

So...
What can replace steel?
Or should it be engineered steel?


 

Offline damocles

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Re: What is "Stronger than Steel"?
« Reply #1 on: 10/06/2013 22:14:04 »
Steel piano wire is the strongest material in tension, volume for volume, but nylon filaments are stronger weight for weight. Carbon fibre comes in between on both measures.
 

Offline evan_au

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Re: What is "Stronger than Steel"?
« Reply #2 on: 11/06/2013 12:02:08 »
One of those materials often quoted as "stronger than steel" is spider silk.

Just as there are many steel alloys, so there are many species of spider, and most spiders produce several different kinds of silk for different purposes - some emphasising tensile strength, some toughness, and some because they are sticky.

It is really a question of "Stronger than steel in which application?". For example, some kinds of silk stretch when they get wet - this might be a problem in some applications. You also need to consider failure modes - if you exceed the rated load, does it fail gracefully, or catastrophically? (Composites share the load across many fibers, and so tend to fail more gracefully.)

But the claim usually comes down to the fact that spider silk is less dense than steel, and so the comparison is often qualified by "stronger than the same mass of steel".

I imagine that the same caveat applies to kevlar, carbon nanotubes, diamond and graphene, which are also sometimes the subject of similar claims.

See:  http://en.wikipedia.org/wiki/Spider_silk#Strength
 

Offline Bored chemist

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Re: What is "Stronger than Steel"?
« Reply #3 on: 11/06/2013 14:03:00 »
Dollar for dollar, aluminium and timber may be stronger than steel
 

Offline bizerl

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Re: What is "Stronger than Steel"?
« Reply #4 on: 18/06/2013 02:24:43 »
I've also heard anecdotally that living bone is stronger than steel, but again weight for weight.

It's always a bit of a headline though. I'm not sure I'd want to pit a ball bearing against my tibia, even if they did weigh the same. And I'm sure a jagged piece of wood would do quite a bit of damage to a sheet of foil of the same weight.
« Last Edit: 18/06/2013 02:27:16 by bizerl »
 

Offline syhprum

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Re: What is "Stronger than Steel"?
« Reply #5 on: 18/06/2013 07:43:36 »
Is it not time we adopted a different name for the small steel ball used as projectiles ? they are not bearings but the balls used in bearings should we not call them bearing balls ?
 

Offline CliffordK

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Re: What is "Stronger than Steel"?
« Reply #6 on: 18/06/2013 20:41:20 »
I've also heard anecdotally that living bone is stronger than steel, but again weight for weight.

The body can be quite extraordinary.
While a grinding wheel can do nasty things to flesh, I have used my fingers to guide a file, capable of cutting steel, but not too damaging to flesh (at least with a light touch)

Leather can be surprising resilient to a variety of environments.
 

Offline shagydeep

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Re: What is "Stronger than Steel"?
« Reply #7 on: 02/07/2013 12:06:23 »
Hello,
uuhhh nothing is stronger than steel... O8)
 

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Re: What is "Stronger than Steel"?
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