Problems (see photo)

D

deloid

Joined
Dec 19, 2007
Messages
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This is a forged knife I was trying to make. It had been heated red hot and hammered probably too many times without normalizing the metal.

This last time I put it in the forge, sparks flew as I hammered and it developed an edge crack. I seem to remember reading that sparks in this manner comes from burn off of the carbon -from overheating or from stressing it partially hardened?

Anyway, You can see the pits and the crack.

I thought about folding it to start over (weld) but I don't think it can be welded now with the pits...true?

200804060462copypk0.jpg
 
It looks like you burned the steel. If that is the case then it is worth nothing but the lesson. A couple of questions what is the steel? and what is your heat source? It may have been easier to tell if you had not ground it down. Either way welding would not work with those pits and the cracks would not be worth trying to fix. If there is enough steel there cut off the burned portion and use the rest if not put it in the hard lessons box.
 
That's well above "red" hot !! I think it is burned too. At the point where you burn the steel oxygen has penetrated deep into the grain boundaries and the steel cannot be salvaged !
 
mete said:
That's well above "red" hot !! I think it is burned too. At the point where you burn the steel oxygen has penetrated deep into the grain boundaries and the steel cannot be salvaged !
Click to expand...

So, when your forging, how do you know when the steel is too hot? (Time for a "duh") How do you "normalize?"


Jim L.
 
Most steel should be forged between 1800-2000F unless you are doing Damascus then it goes up to 2500-2450F. higher alloy steel should be in the lower end of the 1800-2000. The biggest problem with burning steel is the atmosphere in the forge. A reducing atmosphere is generally the best for basic forging. Start forging at the light red orange heats. If it goes above yellow it can burn easily. If you have an oxidizing fire it will also burn easily. If you are using a coal forge then make sure you have a good bed of coke under the steel. If you are using propane feathers of flame coming out the front 4-6 inches. Normalizing is heat to nonmagnetic and let air cool (simplified version). Do not need to do it during the forging process just when finished and would not hurt again after grinding. 2-3 times should be sufficient. Oh we do not know what steel you are using??? If you are using 52100 or O1 or the like heating it to the yellow heats will turn it into "oatmeal". DO NOT FORGE THESE STEELS TOO HOT. They crumble. You normally do this a couple of times but for some of us 5-6-7-8 times and we still don't learn.
 
Are you using coal or propane? Watching the color of the steel is very important. Be sure it is at least red to orange before hitting it. Is you forge inside or outside? Its hard to tell what color steel is if you are in the bright daylight.

To normalize you will need to get control of the heat. Bring the shaped blade to just above non-magnetic and let it cool to black at least 3 times. Do not overheat or you will have trouble later with warping and weak steel from stress and/or grain growth.
 
I was using an Ellis forge (propane) and the metal is from an ancient file that I was told by a 90 year old smith was 1050 but I thought was W2. To be safe I only forge at red and at most red orange.
THE biggest difference today on this steel that was looking like a nice 10" dagger was that I was using my new didymium glasses so the color I saw may have been wrong AND my wife may be stronger than I thought as she beat the flatter with a sledge.
 
If you burned 1050 or W2 in a propane forge then your atmosphere is way too oxidizing. If you were outside in a sunny local this can also through you way off. Put the forge in a subdued light area. Use your Didymiums but make sure for general forging you have a reducing flame. Then keep an eye on it. Better yet get an inexpensive pyrometer and keep a check on the temps.
 
Another thing on the lesson aspect. Break it where its is burned. You should be able to see the grains, they will look huge. Then break a new non forged file and look at the diferance. Big grains are bad:)
 
William,

Am I correct in assuming that I should harden (quench) both before breaking?

I do want to see the difference.

Thanks-
 
Being new at this I guess i'm allowed to be confused.
What is a reducing flame (atmosphere) as compared to a reducing flame?

I thought it was just the heat of forging but I'm pretty sure I'm missing some important info-
 
Reducing atmospheres basically have an excess of fuel (propane) within the forge, and the escaping fuel will burn as it exits the mouth of the forge. You want orange flames coming out of the front of the forge 4+ inches. It uses more fuel, but has less oxygen in the forge to burn up your steel. Also, if my understanding is correct, it won't run quite as hot.

Oxidizing atmosphere is where all the fuel is consumed within the forge. More oxygen inside the forge, higher temperature spikes, and more chance of burning up your steel or getting deep pits.

--nathan
 
Which is better at producing a reducing atmosphere-
-venturi burner?
-Forced air burner?
 
Hi Dean,

Being new, my guess is you are probably running the forge too hot. You got both the venturi burner (1") as well as the Forced air burner with your forge. With the Venturi, it naturally runs slightly reducing, so it's not an oxidizing flame that is creating your problem, but that 1" Venturi burner will get your forge very hot...as you know. If you've got your blower hooked up to your Forced-Air burner, it may be either case. You want flames coming out of the front of the forge for a reducing condition. My suggestion would be to use your pyrometer for a bit until you get accustomed to what the colors look like when running at different temperatures, and once you do, you'll only need it when heat treating to dial it in exactly. Give me a call if you want and we can discuss in further detail.

:)

-Darren
 
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