# How hot is red-hot iron?



## Anabstercorian (Feb 10, 2005)

Similarly, hot hot is white-hot iron?  And does the color glowing vary depending on the metal?

My character is planning to create a portable, magically-powered forge, and I want to know just how hot this thing is getting.  Some of the numbers I'm going to make up (the melting point of Mithril or Adamantine, for example) but I'd like real world references for the rest if possible!


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## Phineas Crow (Feb 10, 2005)

I'm far from an expert, but from what I understand it makes little difference what the object is, the temperature determines what spectrum it glows.

Objects take on a dull red glow around 1100F and objects become white-hot at about 5000F.


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## Torm (Feb 10, 2005)

Iron's "red-hot" temperature is right at 700 degrees Centigrade, "white-hot" temperature is at 1094 degrees Centigrade, it becomes viscous enough to pour into molds at about 1100-1150 degrees Centigrade, and its melting point is 1538 degrees Centigrade. Also worth noting is that at about the same temperature it becomes red-hot, it is no longer magnetically responsive.


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## Andor (Feb 10, 2005)

According to my pocket reference book Iron glowing red visible in daylight is about 1000 deg F.

White hot it 2550 deg F. 

Yes the type of iron (Wrought, cast or steel) affects everything. 

To temper steel you don't really need to get much hotter than 600 deg F depending on what hardness you want.

Checkout www.anvilfire.com for lots of information about blacksmithing.

It occurs to me that an Iron golem or equivilent animated widget would be strong enough to run the bellows for a Bessemer furnace. Which would make steel very very cheap. Of course that's the sort of world changing innovation that happens all the time in real life, but for some reason breaks peoples suspension of disbelief in a fantasy world.

-Andor


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## BryonD (Feb 10, 2005)

Red: 8d6
White: 14d6


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## Mercule (Feb 10, 2005)

Torm said:
			
		

> Also worth noting is that at about the same temperature it becomes red-hot, it is no longer magnetically responsive.




So, does that mean that _Heat Metal_ can be used to counter an _Attraction_ spell?


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## The Grumpy Celt (Feb 10, 2005)

Anabstercorian said:
			
		

> Similarly, hot hot is white-hot iron?  And does the color glowing vary depending on the metal?




Hotter than toast, not as hot as the surface of the sun in the middle of the afternoon.


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## Galethorn (Feb 10, 2005)

To put things simply, you'll need the forge to get the metal into the 1700 degree F range to forge it (the part where it's hot and you hit it with a hammer) [orange glow], the 1500 degree range to harden it (the part where you get it hot then quench it) ['cherry red'], and the 300-600 degree range to temper it (the part where you bake it to make it a lot less brittle, but a little less hard as well) [surface gets a yellow/blue/purple/black oxidation layer (depends on specific temp)].

So, you'll want at least 1700 degrees to work with...2500 would be better.

Oh, and you should keep in mind that the melting points for the hardest-to-melt metals in the real world are in the 2000-3000 F range, so adamantine would likely need to get into the


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## Richards (Feb 10, 2005)

> Hotter than toast, not as hot as the surface of the sun in the middle of the afternoon.



Um, how does the fact that it's the middle of the afternoon have any bearing on the surface temperature of the sun?

Johnathan


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## Crothian (Feb 10, 2005)

Richards said:
			
		

> Um, how does the fact that it's the middle of the afternoon have any bearing on the surface temperature of the sun?
> 
> Johnathan




because the sun is highest in the sky and that is when it warmest here...therefore the sun must be at its hottest point.....


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## Dr. Strangemonkey (Feb 10, 2005)

Richards said:
			
		

> Um, how does the fact that it's the middle of the afternoon have any bearing on the surface temperature of the sun?
> 
> Johnathan




Middle of the Afternoon is a climactic template.  Any environment it is applied to becomes hotter by multiplying the normal range by 125% and giving the local heat source a base hit die one die size larger than normal.


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## Abisashi (Feb 11, 2005)

Dr. Strangemonkey said:
			
		

> Middle of the Afternoon is a climactic template.  Any environment it is applied to becomes hotter by multiplying the normal range by 125% and *giving the local heat source a base hit die one die size larger than normal.*




So I shouldn't fight fire elementals during the day?




			
				Mercule said:
			
		

> So, does that mean that Heat Metal can be used to counter an Attraction spell?




It will in my campaign from now on   .


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## Anabstercorian (Feb 11, 2005)

*Janeko's Fiery Crucible*: This device is an adamantine folding forge powered by magic.  When folded, it fills approximately half a cubic foot, and when unfolded, opens in to a two-foot cube with one open side, and shutters that can be drawn to decrease the size of the aperture on the open side to as small as three inches squared.  A prepared spell with the [Fire] descriptor can be cast 'into' the crucible, such that it is used to power the forge instead of having the normal effect.  The forge, when thus charged is magically held at a high temperature for one minute per caster level, and then cools normally – thus, it is most efficiently used when kept well insulated, so that the burning heat within can be contained longer than otherwise.  The heat reached inside the box varies by the level of the spell cast in to it, like so:
Cantrip: 300 to 400 degrees Fahrenheit – a normal kitchen oven.
1st level: 400 to 800 degrees Fahrenheit – hot enough to temper steel.
2nd: 800 to 1200 degrees Fahrenheit – Metal glows red-hot. 
3rd: 1200 to 1800 degrees Fahrenheit – Metal glows orange. You can forge and harden iron.
4th: 1800 to 2600 degrees Fahrenheit – Metal glows white-hot. You can forge and harden steel.
5th: 2600 to 3200 degrees Fahrenheit – Iron melts. You can temper mithril.
6th: 3200 to 4000 degrees Fahrenheit – You can forge and harden mithril.
7th: 4000 to 4800 degrees Fahrenheit – Mithril melts. You can temper adamantine.
8th: 4800 to 5600 degrees Fahrenheit – You can forge and harden adamantine.
9th: 5600 to 6400 degrees Fahrenheit – Melt adamantine (destroying the crucible in the process) (5600 to 6400 Fahrenheit.)


(Note: For Adamantine, I used the melting point of Tungsten.)
(Clearly unfinished – I'll get back to this shortly.)


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## Tommi (Feb 11, 2005)

Just a note about heat treating steel. You have to be above phase transition temperature before quenching (steel is not ferromagnetic above that temperature - will not stick to magnet). Quenching means that you 'freeze' the metal in unnatural cyrstal structure. Tempering is basically lessening hardness and relieving stress. Yuor magical forges most important feaure should be the maximum reachable temperature for forging and quenching (also the evenness of the temp) - tempering is easy. 
If you want realism in your fantasy???? Your forge should also include freezing option. Some steels need to be frozen after quenching to complete the phase transformartion - you get stress free and 100% martensic steel while roomtemp may only give 80%... Also oxygen free enviroment could be nice. I might go on for a long time...

BTW As you seem to want realism you should drop hardening iron option as you can't harden iron. Steel is hardenable because of cardon. Iron alloy (conventional not particle metallurgy steel) with 0,15% to 2% C is considered to be steel.


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