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Normalizing/Anealling

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I'm thinking my alan wrench blades may be A6 or similar air hardening steel, it forges easy though unless i get it to thin.

Can't wait to get a bigger blower so I can do some welding :)

Edited by dracozny

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Tai, don't get too carried away with the generic applicability of the word "normal" as used in "normalizing". After all, there are terms "marquench" and "austemper" that are not so readily explained by their root words. They had to call it something and for reasons lost in antiquity, they called it normalizing. I think "Pearlitizing" would be more appropriate. In fact, we could call annealing "Ferritizing".....except when you do it to a non-ferrous metal...then the whole scheme goes to H*ll.....never mind. :blink:

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(...disregard this entire thread!)... :D

Edited by Tai

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Chuck, I went back and re-read what I wrote. What I wrote is correct. Normalizing will re-distribute the carbon and achieve more uniform hardness. This will reduce the tendency to crack. Multiple normalizing CAN reduce grain size IF you have been forging very hot and had a lot of grain growth. I have slightly altered by opinion of this practice due to the widespread mis-understanding and mis-application of normalizing and annealing. I am in agreement with Tai that unless you understand the subtleties of the processes, you are probably better off keeping it simple. For example, forging at a dull red may not be the best practice for high carbon steel. You will have to forge hot. It the steel is a simple carbon-manganese steel, there will be nothing to prevent grain growth. If it is a high alloy tool steel,like D2 or an A2, you will not see the grain growth because the alloy carbides at the grain boundaries keep the grains from expanding into one another. A simple receipe for heat treating is difficult to come up with because there are so many different steels, different forging practices, and cooling rates between heats. That article was not intended to give you receipes, it was a basic lesson on how to cook.

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I think 10 series steels are the most responsive to thermal treatment. That's why I like them. You can grow the grain to the point that it looks like 50 grit sandpaper, and completely reverse it in just one thermal cycle.

 

If your fractured surface looks like the "dull luster" on a piece of fractured flint, for all practical purposes, it's as refined as it will get. :)

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"Multiple normalizing CAN reduce grain size IF you have been forging very hot and had a lot of grain growth." RKNichols

 

I firmly agree. It only helps "if" there is a problem or abnormality present in the blade. :)

 

I don't have a problem with "ritually thermal cycling" after forging. However, that's all it is,... "RITUAL"! It may or may not be doing a darn thing.

 

Ritual or ritually means: The prescribed order of a religious ceremony.

Example: I ritually thermal cycle my blades 3 times after forging.

 

If it makes you feel better,... fine!

Edited by Tai

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As Tai said, if the fracture glitters, you have very coarse grain. Dull, sooty fracture surface is indicative of ductile shear fracture across very small grains. That's the good stuff and you really want it through out the blade. :P

 

 

Rituals: Tai, what effect does a full moon have on the quality of the blade? Or does it just make it easier to find your beer while you take another heat? :D

Edited by RKNichols

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ROBERT N.> I have ordered some TEMPRIL STICKS. I will see if I can more readily establish a color (temp) pattern, that I can recognize on the 1095,5160 and 52100 steels. I am currently staying with the first two steels. Later I will re-start my attempts with 52100. I will continue to try to draw the grain size down. The controlled normalizing and annealing, with triple quench of the lower third of the blade and etching to see where my heat is going. I do not intend to harden the spine or top of the blade, except from residual heat from the bottom third of the blade. I have been quenching the bottom until the spine loses its color then quenching the whole blade. I will temper the entire blade, two or three times. Do some more testing and see where I am headed.

Right now I am working on a railing and some stock removal blades. I will continue my testing after I finish this other stuff.BOG

 

Chuck

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As Tai said, if the fracture glitters, you have very coarse grain.  Dull, sooty fracture surface is indicative of ductile shear fracture across very small grains.  That's the good stuff and you really want it through out the blade.  :P

Rituals:  Tai, what effect does a full moon have on the quality of the blade?  Or does it just make it easier to find your beer while you take another heat?  :D

22682[/snapback]

 

 

The full moon light makes the blade much better. This is because you CAN "see" it better at night when the moon is full and there is more light. :)

 

I've learned so much!

Edited by Tai

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I think I have a much better handle on it now guys....

 

If someone were to say to me, "Tai, I ritually thermal cycle my blades 3 times after forging to drive the Gremlins out,... just in case there are any present after forging."

 

I'd have to say, "Hey, far out dude! You got to get them boogers out!" :D

Edited by Tai

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There's Gremlins in the steel!

 

There's Gremlins in the steel!

 

Oh lordy what can we do?

 

Don,... Jimmy,... Oh lordy! What can we do ???...

 

LOL :lol:;):unsure:

Edited by Tai

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Chuck, sounds to me like you got it by the horns.

 

Tai, never seen gremlins in the steel. Did find some holes in a casting that I was told were made by steel beetles, though.

 

I need to get the old forge fired up soon. My elbow seems to be on the mend after two months. I have to finish some goodies for my Dutch oven. Then I am going to make a Mole Gig. I got moles in my yard bigtime. Tried eveything Lowes sells to eradicate them. I figured a two or three pronged fork with straight tines about 16" long made of 3/8" rod would make for an interesting time for some unsuspecting mole. :o then maybe I can finish the 5 blades I have left unfinished for the past 3 months.

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I tend to think that 'thermo cycling' starts from the moment I put the steel in the forge , thru the forging process, up to and including hardening and tempering cycles.........I do not 'anneal' the steels I use (non air hardening) as I see no purpose (I can file and grind with no problem).

 

My 'normalising' process is part of my theromcycling which prepares me for quenching......Although I think that my steel is 'normal' by the time my last few hits of my hammer strike the blade (constant reducing temperatures)...I then also 'ritualy' normalise what is for all intents and purposes a normal blade three times..........its a habit I cannot kick...so I guess I need some help .....:unsure:

Edited by coutel

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COUTEL> Have you ever done any testing to see how fine a grain you have on your steel? I have done a little checking. The grain is more refined compared to one noramlizing and one annealling. Some times I don't have to anneal at all and some times I do. If I have any hardnest in a blade after normalizing, I will anneal. How often do you have to straighten a blade?? The annealing seems to work on the warpage.

 

Chuck

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COUTEL>  Have you ever done any testing to see how fine a grain you have on your steel?  I have done a little checking. The grain is more refined compared to one noramlizing and one annealling. Some times I don't have to anneal at all and some times I do. If I have any hardnest in a blade after normalizing, I will anneal. How often do you have to straighten a blade??  The annealing seems to work on the warpage.

 

Chuck

22707[/snapback]

 

 

Chuck....I test and snap plenty.....I now use a broken 'tap' as a good base line (picked that tip up here) for checking my grain, so thats what I aim for.....and I seem to be close, if not there.

 

Warpage is something that I very rarely see.....(touch wood!)...

 

I have done tests on overheating stock steel (not forging to a blade)..then snap 3 test peices and normalise 1,2, and 3 times.....The change in grain from zero to 3 is huge...like sugar to silk ......and there is noticable difference between 1 and 2 to 3......(a fourth doesnt seem to make a noticable difference to me).........BUT thats about as scientific as I have gotten...and its unrealistic compared to careful forging...as Tai suggests......by the end of the forging, the blade should be 'normal' anyway.......... I have also snapped blades without the additional 'ritual' 'normalisation ' cycles and can see no difference........

 

IF I were to make a billet of damascus and not forge to a blade, but make a blade just by stock reduction ...then I would go through a triple thermal cycle to de stress the steel.....I still wouldnt see any reason to 'anneal' as the thermal cycling to bring the steel back to what I consider a 'normal' state leaves the steels that I use in a soft enough state to work anyway.

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I think with most normal steels, 3 "heats" either at the end of the hammer finishing, straightening, in the normalizing and annealing, (or one time in each=4 thermal cycles from just above critical,) will get the grain pretty near as fine as it will get,... ultra/normal. :)

 

... a few extra, ( like 12 to 20), probably won't hurt.

 

It might take some smiths 12 heats after forging to get the blade normalized. It might take others only 1. It just depends how good you are!

 

Isn't it true that you can also get some grain refinement just by doing a good job in the hardening cycle? Isn't it true you can also get grain growth by doing a poor job hardening?

 

I think we are all pretty much in agreement. We each use some of the words a bit different and look at things from different angles, but in the essence of the process it all boils down about the same things. :)

 

I don't think we can explain or justify what we do completely by metallurgy. There is a ritual aspect to all of it. We each have to get rid of our own gremlins...

Edited by Tai

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COUTEL> Thanks. I tried to reply to the other message and pics. Messed it up some how. Grin. I have not had quite so nice a refinement. I am closer now and will keep after it. This will help me. I anneal when I can not scribe a center line. Thanks: Chuck

Edited by CBENNETT

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I just found this new can of worms and I thought I would go ahead an open it. <_<

1. Every time you heat the steel into the austenitic range you will form new austenite grains. The hotter you heat it, the bigger the grains will be. The grains do not get smaller as it cools down.

2. Heating it many times (thermal cycling) to about the same high (forging) temperature will not make the grains smaller. They may actually grow a bit more. It should help to dissolve more carbides, though.

3. To make the grains smaller, you need to heat it to lower temperatures but still hot enough to form austenite. You cannot really do this while forging because high carbon steels can crack if you forge them too cold.

4. Multiple normalizing will do the following: a) dissolve carbides into the austenite and make the carbon distribution more even. B) Relieve stresses formed in forging and cooling. c ) Make the austenitic grain size smaller and smaller if you normalize at successivley lower temperatures. There is a practical limit to this and 2-3 is probably it. How much better it is than doing it just once cannot be readily determined.

5. Very small grains are tougher than big ones but the steel loses some ability to deep harden with small grains. A blade will cool fast enough that you would probably never see this effect, however.

6. If you quench the blade instead of normalizing, you will see much the same benefits. However, you do run the risk of distortion and cracking by multiple quenching. Martensite will transform to austenite faster than will pearlite but this is not a big benefit.

 

The $64 question: Has anyone tried to form martensite on the edge and BAINITE on the sides and the spine? If so, how did you do it and how did the blade perform? :huh:

Edited by RKNichols

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The $64 question: Has anyone tried to form martensite on the edge and BAINITE on the sides and the spine? If so, how did you do it and how did the blade perform?

 

I've tried before, but didn't get the results I was after. I thought it would be cool to get some lower bainite in the spine and martensite on the edge. What I thought would work would be to marquench the blade, interrupt it when it got to 900, edge quench in ice brine to get it just under 400 with the spine still above ms, the stick it back in the 450f oil and let it sit 'till bainite formed on the spine. I tried it with some 5160 and I had to cut it short 'cause it started to rain :( had to abort since I didn't have a roof over my head back then :rolleyes: Haven't tried it since.

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R K > AL PENDRAY, ED FOWLER, WAYNE GODDARD, RICK DUNKERSLY(SP), REX WALTERS, not neccessarily in this order, have done a lot of research and testing along the these lines. Any one of these men could answer some of your questions. I don't know which, could answer the most questions. I would like to be a silent observer in a conversation of this sort. ED is VERY helpfull in any way that he can be. He probably would not relish a debate. I have talked to him a couple of times, but did not know enough to ask the right questions.GRIN I plan to at some later date, after learning enough to ask the right stuff, to travel to ED'S place. A few days in his shop would move me several years up the road on heat-treat.grin.

These guys are all ABS MASTERS- The phone numbers can be found in the ABS member-lists.

 

Chuck

Edited by CBENNETT

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don't forget Howard Clark.... and his L6

 

anyhow.... just a quick quench in a fast medium to get the edge into MS and keep the thick spine out of MS....... then into the hot oil and hold till spine makes bainite.....

this is what I thought might work... and posted it on SFI awhile back

 

Greg

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RK. That's all good stuff, but I would add on #3. That depending on the type of steel, the skill and experience of the smith, some straightening and light forging may be accomplished from lower temperatures.

 

The $64 question is great and all, but I still don't think any special heat treating is necessary to get the type of blade Chuck was talking about. What he brought up was normal. Let me go back to that once more.

 

" I would really like to make some good blades. that will cut and cut, with the ability to flex to thirty or so degrees and come completely back. When they need to be resharpened, my clients can do this in the woods or where ever. Make sense???" CBENNETT

 

Nothing special needed to do this.

 

So, why might blades come up abnormally brittle?

 

One thing might be fatigue from over working and or too many heats. Isn't there a limit to how many heats you can take on a given blade before it starts to fatigue the steel? Won't bending the steel back and forth hot also eventually fatigue the steel?

 

Here's another "can 'O worms".

 

"If" there is nothing wrong with the steel itself (and that's a big "if"), a good job was done in the forging, no over heating or fracturing occurred, the thermal processing was all "normal" and nothing abnormal was done during these steps,... there still might be a few reasons for brittle blades. What I'm getting at is, "steel contamination" from the fuel, forge lining, or forge/furnace atmosphere itself.

Edited by Tai

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