Cracked damascus.....please help!

happycat

happycat

Joined
Jun 21, 1999
Messages
752
:( Some days it just don't pay to get out of bed. First it was my cat getting run over, then this.....Sometimes, I wish life had an edit function.
This is some O-1/1095 damascus we made at the blade school last summer. I foged it last week and heat treated it today. I file tested and heated and quenched again cause it wasn't very hard. When I started cleaning it up I noticed the cracks. I've outlined them with a sharpie.
I forged it bright orange hot and was careful not to hit it cold. Normalized x3. Ground it. Normalized x3. Then heated to non magnetic and quenched in heated olive oil (very quickly..1-2 seconds from forge to oil). I let it stay in the oil for about 5-10 min then wiped it off and washed it in warm water....
Any ideas on what went wrong and how to avoid doing this in the future?
Also, I am contemplating trying to salvage a smaller blade out of this mess. Is that advisable? I'd re anneal and then grind it down. Any input would be appreciated.
Thanks,
Ed
 

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Cut it in half stick a chunk of 1095 in the middle and call it san-mai :D

Was it edge quenched Or a full quench?

You might have taken too long getting it into temper. I only leave mine in the oil until they are cool enough to hold like a hot potato. Then a quick wipe down as I'm walking towards the preheated oven.
 
It all sounds OK but, for the hot water thing. I don't know if that's a good or bad thing, I've just never done it. I wouldn't have expected those kinds of cracks though, wow. Well, you can try to get a necker out of it and cut the unusable piece up for frontier damascus, or yoou can chop the whole thing up and we'll throw it in a can when you come up.
 
I don't know what caused it but: ramp slowly to pre-heat and allow to pre-heat a very few minutes before going to non-magnetic. The steel expands at pre-heat and contracts at non-magnetic. Rapidly going to austenitizing before the steel cross section has a chance to equalize at pre-heat can cause the inner parts of the steel to both expand and contract simultaniously. This usually, from what I believe, causes warp but may also lend itself to cracking - but I do not know for sure about the cracking.

RL
 
I certainly don't know what caused the cracks, but I have been told that anytime cracks are running lengthwise with the blade, you were to hot going into the quench.
 
I didn't anneal, just normalized 3 times. I did do a full quench rather than an edge quench. The oil was hot to the touch, but not scalding. I know I should get some accurate thermometers for the oil and afor the forge, just haven't got round to it.
I did straighten a tiny bit of warp during my heat for the second quench. then I heated it up again and did the second quench.
Who knows.....maybe my grinding was off or something. Could have been any number of things I guess. Chalk it up to the learning curve... I've been pretty lucky so far, first time this sort of thing has happened.
Ed
 
You must know what the quenchant temperature is before quenching and a pre-heat cycle will help eliminate warp. Ramp quickly from pre-heat to austenitizing and inexpensive thermometers for monitoring the quenchant are available at common super or discount stores. I bought a digital for a bit over 20 bucks and have a couple other types for less than 10 bucks per. It is a whole lot less expensive than guessing at the single most important part of knife making - the HT.

RL
 
I use a candy themometer from Wal-mart. I think it was about $5.00. I'm gonna show my ignorance here Roger...what does the term "ramp" mean? I understand everything but, that term. I know I've seen it in print before too.
 
All of the above is great advice and information, and one other thing that may have contributed towards the cracking is that 0-1 is a deep hardening steel, while 1095 is shallow hardening and both have different heat treat procedures when done seperately. Mixing the two may have made them expand/contract differently during the heating and quenching, resulting in the cracking. I've seen other blades with this mix of steel, so I obviously it doesn't always work out this way, but it sure couldn't have helped! Keep it in mind when you make up more damascus in the future.

Clint

www.chisanknives.com
 
I think Clint is close on this one. Sounds like 2 completely different tool steels, with completely different quench speeds. Doesnt sound like an ideal mix to me. O1 being an oil quench steel with a slow quench speed, and 1095 which actually needs a super fast quench. My guess is, the quench was too fast for the O1.
 
I've been watching this thread thinking the same thing as Clint. When I make Damascus, even though I joke about Junk Box Damascus, I know what is going in. I try to use steels that are very close in heat treat properties. The filler is always mild steel.

I have had this happen too many times using vastly different steels. Everything from delamentation to cracks and I had one blade that just shattered.

That would be my best guess but it is only a guess. Sometimes the steel plain doesn't like you!
 
I can't say for sure from the picture but is the bottom fracture continuous all the way though the blade, it looks like a bad weld to me and the quench shock opened it up, as for the upper fractures I can't see anything on my pc except the sharpie marks, . Several things could cause the problems, but I don't think it was anything during your heat treatment, unless you terribly over heated before the quench. Was the damascus a twist,random, etc pattern or what? The cleaning up a bar of welded pattern steel before forging to shape can prevent a lot of problems. When a twist or highly manlipulated pattern is forged to shape with out clean up before hand you have a tendency to close any exterior shuts and inclusions with the hammer, then these problems magnify and grow bigger problems when heat treating. I'm not saying this is what happened just that it might be something for you to think about when trying to figure out the problems at hand.

Good luck,

Bill
 
HI Happycat,
I tried your e-mail as listed on forum and no joy.
Here is the e-mail I tried to send:
That looks a lot like the piece that you made with Foster at the Moran School. I watched the heat as it went together and it is the same as I do it. Chances are it was stress in the quench that got you.

The san-mai idea is not a bad one. I don’t know its current thickness. I would be inclined to draw it out thinner, cut, grind smooth, and put a piece of 1095 or 1084 between the pieces and draw it out in a press or rolling mill. Or lots of hammering. Clean surfaces, flux, and a reducing flame are a good thing. If you like, send it my way, I’ll try not to make it any worse, and then I can send it back. I still have 1095 and 5160 scraps from Moran School, our class, so you can still call it made from class materials.

Sorry to hear about your cat. We used to have them. One gets into my shop every now and then. I have a hard time getting mad at it.

Enjoy, Ken



Member ABANA, ABS, NCCKG

Democracy is two wolves and a sheep voting on the menu. Liberty is a well-armed sheep.

PS: PLease send me an updated e-mail address
 
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