|
Joined: Jan 2001
Posts: 13,858
Carpal Tunnel
|
OP
Carpal Tunnel
Joined: Jan 2001
Posts: 13,858 |
I think we had posts about this a long time ago. I searched, but never got an answer. But I suspect that few members have ever needed to know what it means. Heat treatments can be crucial to obtaining desirable qualities in quite a few products. For instance, the life expectancy of the crankshaft in your auto engine depends no only on the composition of the steel, but the heat treatment it got after it was forged and machined.
From the armour glossary again: Anneal: The process of softening metal. For ferrous metals, that is those containing iron, the process involves heating the steel up to its critcal temperature and then slowly cooling it. For non-ferrous metals such as brass, bronze, silver, gold, aluminum and the like, the process is exactly opposite. The metal is heated to the critical temperature and then quickly quenched in water, snow, urine, or oil. What annealing actually does on a molecular level is to allow the metal crystals to realign, moving them into their more relaxed state. When the metal is worked, the crystals are moved out of alignment, contributing to both hardness and brittleness. Practically, in the production of arms and armour the metal must be annealed as it is worked, otherwise the metal might stress enough that it will crack.
|
|
|
|
Joined: Jan 2004
Posts: 1,475
veteran
|
veteran
Joined: Jan 2004
Posts: 1,475 |
I learned this word while studying AI (artificial intelligence). There's a technique, written up by its inventor at the U of Rochester, called "simulated annealing". From OE onælan 'to set on fire'.
|
|
|
|
Joined: Jan 2001
Posts: 13,858
Carpal Tunnel
|
OP
Carpal Tunnel
Joined: Jan 2001
Posts: 13,858 |
I learned "anneal" in the bad old days before Pyrex glass became available. For instance, if one tube had to be joined to the end of another, the flame had to be very hot to make glass of each end fuse,obliterating the seam. But then you had to cut off the oxygen, lowering heat of flame very much, and let the molten place slowly drop below melting point, or the joint would be very fragile. The opposite was "Prince Rupert drops" made by melting a rot of glass over a dish of water, and letting the molten drops with a moderate tail fall into the water. When removed breaking even a tiny bit off the tail caused the who glass to shatter. Automobile windshield used to be annealed. But then when they broke, sword shaped pieces with horribly sharp edges hit passengers in the face. So now windshields are tempered so that even a small scratch may cause them to shatter into hundreds of fingernail sized pieces.
|
|
|
Forums16
Topics13,913
Posts229,423
Members9,182
|
Most Online3,341 Dec 9th, 2011
|
|
0 members (),
793
guests, and
3
robots. |
Key:
Admin,
Global Mod,
Mod
|
|
|
|