Anyone else find 1084 prone to warp?

[ricky_arthur]

I have 5 smaller knives in the works and 2 of them I promised to have ready for Valentines day. So I got all 5 ready for heat treat. Did 3 normalization cycles. Quenched the first one, no problems. Quenched the second (the only one that was Hollow ground) And it warped all to heck. I threw it back in the forge to anneal it and got the 3rd ready. It was the largest of the 5. It warped too. Since both were promised by tomorrow, I couldn't risk breaking them by straightening them after quench. So I annealed both, straightened, and re quenched. The larger one came out good, the hollow ground one warped again only not quite as bad. I decided to temper them all and see if I could straighten it after tempering.

So after temper I took them all to the shed to clean them up. I noticed one of the others had a very slight curve right in the center between the blade and handle. I walked over to the anvil and tap, tap, tap. Nothing, tap, tap tap...Nothing

TAP!

Danggit!

I know everyone loves 1084, but I never had a 1095 blade warp on me, I'm about to switch back. At least 1 out of 3 with the 1084 will warp. Even small ones.

anyway, I decided it was a good opportunity to check grain size and so I cut it in half, and was pleasantly surprised. A pic is hard to see because the light makes it look funny but in person the grain is small enough that it is hard to see grain with the naked eye.



I was wondering how The grain would look using my heat treat method and now I know. I guess it was worth throwing about 3 hours of work in the garbage.

 

[One]

What did you quench them in? My guess is that it may be too fast for that 1084 and geometry.

 

[Brad Lilly]

I have had good luck with 1084. When it warps on me it is my fault, like tipping it to one side during the quench. Just a suggestion but if I warp the handle or tang on one of my knifes I draw the temper way back with a torch then straighten it. Of course that will not work on the blade.

 

[ricky_arthur]

I used texaco 70 for quench. Shouldn't be too fast.

 

[One]

That sounds like a good choice, but you never really know until you try it. Warping and cracking can be an indication that the quench speed is too fast for a particular steel and/or geometry. You could either try a slower quench, or changing the steel type and/or modifying the geometry to accommodate the fast quenching medium.

As far as some steel types or alloys being more prone to warping and cracking, it is usually a matter of quenching mediums, (air, oil, water), and quenching speeds. Slower quenching alloys tend to be less prone to warping and cracking.

Was the taping on the anvil striking it with a hammer to try and straighten it, or just tapping the blade itself on the anvil? Hammering on a blade to straighten it, isn’t a good idea.

 

[Darrin Sanders]

I harden a lot of blades made from many different types of steel made by many different people. I don't find that 1084 warps more or less than any other steel. I harden 1084 at 1500 and quench in Parks #50. I quench for about 10 seconds, check for warpage, correct it if there is any, and then back in the oil until it reaches the same temp. as the oil. I find that warpage is much easier to correct at this stage than after it has fully hardened.
Tai is correct in saying that hammering a blade to straighten after H/T is not a good idea. If you have to straighten after H/T it is best to use slow, even pressure in a vise or some other type of straightening jig.

 

[Kentucky]

when we have to straighten a blade after full hardening I use a flat piece of metal a wedge of some kind and a small C clamp..Use the wedge to keep the blade off the bar and then apply presser with the C clamp opposite the warpage..Close the clamp until the blade is just slightly pass straight(opposite the warp then temper. They are usually dead straight after the fist temper cycle..

 

[LRB]

I think your blades are not full hard, or you are very lucky doing that before any tempering.

 

[Kentucky]

I think your blades are not full hard, or you are very lucky doing that before any tempering.

They are full hard.Temp controlled heat treat quenched in parks 50...I learned this method of straightning from Rick Marchand(sp?) Its not a dramatic bend, only slightly..

 

[LRB]

I still think you have been lucky. I believe Rick uses his method after the first temper is completed to lessen the chance of cracking the blade.

 

[Kentucky]

Probably the best idea but Ive never had a dramatic warp to correct..If they were ever bad enough to fear breaking I usally normalized a few times and started over but those have been far and few between.

 

[McClellan Made Blades]

I don't think anyone has mentioned this other than saying edge geometry, but I would look at the, "as quenched thickness of the blade", leaving a little extra meat on the blade at quench, is a good insurance policy against warping, plus you can quench in faster oil to get full hardness, removing .01 to .03 of steel after quench isn't that hard to do. With as much hand sanding as I do, it has become my standard way of doing all of my blades.

Plus I would also mention that during the quench if you do any agitation , and if not you should be, make sure that your moving the bade straight forward and straight back, never side to side, I had my first warped blade a couple of weeks ago, because I put a piece of steel in the kiln with the blade to heat up the oil, I sat the hot piece of steel in the quench oil carefully so not to splash it, in doing so I accidently and unknowingly got a little oil on my tongs, when I went back to the kiln to get the blade out, a little drop of quench oil dripped into the kiln at 1500 degrees, upon pulling the blade out that little drop of oil flamed up, while I had my knife in the oil, so I'm trying to get close enough to blow the fire out before any damage is done, as I would move the blade forward I would blow and then moving it back I'd catch another breath, I just wasn't close enough to the kiln to get a good wind on it, so I moved side ways and BAM! Warped like CRAZY, it's like I felt it. I knew it the second I made that move, that is the first knife I have ever had to warp, so surely I didn't quite know how to fix it and sure enough trying to straighten it, it broke! Looked like it was going to have a sweet hamon on it as well...Oh well, I guess I'll make another one!

Hope this is something that wasn't thought about or covered already.
Rex
BTW, Where did your steel come from, I've only used Aldo's 1084, my opinion, is that it is the best! Could be the difference as to why I've not experienced the same problems that you have...maybe.