Need some help, cracking when forging? and nice to be back!

S

stefanj

Joined
Aug 5, 2007
Messages
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I'll start with my questions first,
I am having problems with cracks forming while forging out my blades or attempting to form a knife. Could this be the result of,
1. Not enough heat (I get a good orange (generally bright glow)?
2. Too much heat, am I screwing up the structure of the steel as a result of toooo much heat (I started to really experience this problem after I built my forced air system which is now regulated and I ran it last at about 3-4 psi for the propane.

The metal at the cracking areas reminds me of the old cast magnesium alloy toy cars I played with when I was a kid. I'm just trying to figure out where I am going wrong!
Thanks for the help!

I haven't been around much since I was working again down at Fort Hood which ment no forging until I returned!:( I did get my next deployment dates and orders for a good school SERE C (I'm excited about the school, hopefully there aren't any problems because I want to go to this course!).
 
Try a little more soak time before bringing it up to forging heat?

If I get in a hurry, I need to back track and hot rasp or grind surface inclusion away before I continue.
 
What type of steel are you forging? Were is it cracking, along the edge, all over? It could be either of the problems depending on what type of steel it is. O-1 will turn to mush if you ever-heat it 10XX will fracture if worked too cold.

By the way congratulations on your SERE school. Never got to go to that one.
 
yes, what kind ofsteel? what color does it look when you are working it, when does the cracking occur and are there any metals other than steel in your fire?

-Page
 
It is some cable from Bruce that I have been working with (great stuff), I did the same thing to some W2 and then a section of cable I had forge welded earlier.
So some soak time should help?
The cracks are near the edges one to couple of inches in from the tip.
I also did it to some old file which was either W1 or W2 (I believe it was W1).
 
Can only be two things with these steels;

Your getting the steel Too Hot and or forging it Too Cold.

Your forge area needs to be on the dark side. You're not forging outside in bright light, are you?
 
What temp are you running your forge at??? If you haven't already done so, You may want to invest in a pyrometer....
 
I guess it is cold shot. I had a couple cracked at the same spot (strangely if it cracks, always cracks from an inch or two far from the tip). I overcome this problem by slow heating and soaking. It seems your blade core was not hot enough as its surface, the color is misguiding as the color is the color of the surface not the core. I guess you forge from tip to tang when drawing. If it is so the tip is always gets hot quickly and when you move to back you suppose it is at the forging temperature as the tip, but it takes much more time to heat the body. To forge from the ricasso to the tip helps a lot with a good soak time...
May be I'm wrong at this but thats what happened to me before....
Emre
 
Yes my forging area is outdoors.
Gala is as I believe probably correct as well as you Don! The outside turns a bright orange even when outside vs a dull red in a quick amount of time. So I am probably not "soaking" the blade like I should, getting the surface intially toooo hot and not getting the core hot enough?
I only started suffering this issue since I made my forced air burner which puts out a tremendous amount of heat vs the weed burner I used before (with better results except for forge welding).

a pyrometer sounds like a good investment, Sears sell any for a decent price?
 
Pyrometer absolutely. Also you need to get the forge under control It actually sounds like your atmosphere may be a bit oxidizing. You need to be able to adjust this so you are not consuming all the fuel in the forge. A few wisps of flame should be coming out the front. If you are running lean and too hot it will decarb the steel and actually burn it. The steel is not spitting sparks is it??
 
Why in the world do you want to go to SERE??? Have fun, hope you're not the war baby.

Not much else to add...
 
I believe there were some sparks.
So run the fire rich (more fuel less air). I was running it last to optimize fuel consumption.
Is there anyways to reverse the decarb process or is resmelting the only way?



Will, because for some crazy reason I like pain.
 
stefanj said:
I believe there were some sparks.
So run the fire rich (more fuel less air). I was running it last to optimize fuel consumption.
Is there anyways to reverse the decarb process or is resmelting the only way?



Will, because for some crazy reason I like pain.
Click to expand...

Oh, so it was real hot ... Not only run rich but also heat slower. Take your time to heat and inspect the heat, try not to overheat. If you cannot be sure what is the temp try to invest a simple thermocouple and a simple display. It is not so expensive investment also...
When you check steel with magnet and it stops sticking note the color of the steel. You need to go up a little bit to some brighter color, if you see it orange or bright red etc. you need to go up to yellowish orange but no further... Try to keep the heat there as the forging goes on, at the later stages it is best to work somewhat lower temp. but dont drop to the noted magnetic point range, it is cold to forge...
I dont think there is a practical way to save that steel. If it is too valuable you can try to harden it, and grind away the unhardened decarb parts. May be it is not too deep....
Emre
 
Grind it clean is the only possible way to save burned material. Even then it may be damaged deeper than you can see. New material is the best. Rich is what you want as far as fire is concerned. Using up a little extra propane is less expensive in the long run than having to redo the knife out of new steel.
 
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