how to recognize a "black heat".

H

hilldweller

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Jan 7, 2014
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complete newbie here, my question is in regards to the color range of steel as it is heated and cools. what do I look for if I wanted to take a piece of metal up to a black heat? black heat is just before dull red, correct? and, it would be around 900 degrees, correct? I would be working outdoors in full daylight, possibly with a little shade. I will likely win most stupid question of day award for this one, but thanks! Hilldweller
 
"IF" you are wanting to look at color, then you really need to be in shade.... dark shade - perhaps late in day, like twilight time frame to better see the colors.
 
thanks for the replies, I am not so concerned with actually seeing this color, just wanting to see if I had a grasp on what black heat is. as far as seeing the various colors, it definitely makes good sense to wait for twilight and that is what I am going to do. so, up to a uniform dull red then back off until the color just fades should be about at a black heat. nothing precise here I reckon, just getting started and sorta got hung up on this term, thanks for the help!!
 
Maybe we could better help you if you will explain what do you want to do.
If you are cycling the steel and want to cool it to black you'll just have to wait until the magnet would stick again.
If you want to heat just to "black heat" you better not overshoot and reach dull red...if you heat in the light you'll definitely reach red without realizing
 
When a piece of steel is cooling down from red heat it slowly gets a duller glow, then stops glowing and looks sort of greyish. Fairly suddenly it takes on a black look. That is black heat. It is the range between 700-900°F.

Try it with a bar of steel and you will quickly see what it looks like.


Warning:
Black heat will fool you. It does not look hot! Be ware - it will still be quite hot, and will ignite a piece of paper placed on it, or burn the crap out of your hand if you pick it up off the anvil.
 
yes, this was in regards to cycling a work piece, in this case getting an old file ready to start stock removal on (prior to the entire heat treat sequence). but, I reviewed some stickys here and found what I was looking for, I sure appreciate the wealth of knowledge that is shared here! hilldweller
 
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