Annealing and Hardening.....

M

Michael_Schaap

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Aug 23, 2000
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I have finally started to work out ideas to get myself forging:) I have made a few knives that were pre made (put handles and stuff on). So I'm setting up the forge (one brick forge) and I am a bit confused..... learning a bit from a blacksmith I noticed that he dumped his forged iteams in water after working with it. I have not seen any mention of this method of cooling in knifemaking. Guess I'm confused as to when do you anneal (what does annealing do for that matter) and when do you use something like "The Goop" (what does this do too.... I know it tempers the blade.... but why would I want to use the goop as apposed to other methods of tempering... like the tempering gizmo that is typically used in the one brick forge for example....).


Michael
 
Michael-

I won't claim to be any sort of expert on this, but I think I can answer your question.

First off, normalizing is believed to be necessary to refine the grain in the steel after you've forged it and ease up on any stresses in the steel. To do that you take the blade up to just past non-magnetic and then let it air cool.

After normalizing you can anneal the blade. You take it up to non-magnetic (slowly and evenly). Then you stuff the blade in a container of vermiculite or wood ashes where it will cool slowly. After that it should be soft and "stress-free."

After the blade is rough ground and cleaned up, you can harden it... take it up a little past non-magnetic and quench it (either edge quench or quench the whole thing tip down). Any oil is supposed to work. I know Wayne Goddard came up with his "Goddard's Goop" by putting wax in with lard and later hydraulic oil. It will get hard when it's cold and is easy to keep from making a big mess with when you're not using it.

With an oil quench you want to pre-heat the oil to somewhere around 130 degrees, some say a little cooler, some say hotter, but this seems to be a happy medium.

Most knifemaking steels can be quenched in oil. Using water as a quenchant is kind of extreme. I know it's very easy to crack the heck out of a blade by water quenching it. Water quench's seem to give the most pronounced temper line, but that's just from what I've seen personally.

The tempering is done in an oven after the blade has been quenched. Most seem to triple temper their blades by putting them in an oven somewhere between 360-460 degrees for about two hours per shot. You draw some of the hardness back out of the blade this way and make it less brittle.

Again, I am not claiming this to be any sort of be-all/end-all info on this...it's just what I've learned so far.

Good luck,
Nick
 
learning a bit from a blacksmith I noticed that he dumped his forged iteams in water after working with it.
Click to expand...

If this was a BLACKSMITH, then that is just normal because the mild steel they usually work with doesn't harden barely at all when you quench it, nor does it stress all that badly. If this was a BLADESMITH, and he was just dropping blades in the water after pounding them out he is what we in the bladesmith community lovingly refer to as an IDIOT.

As for normalizing, I thought that was done not at just above critical, but more like at around 1900 degrees. That's where I do my normalizing anyway. It's really similar to annealing but more comprehensive. Once you reach those sorts of heat levels, the steel begins to function a bit more like glass than like steel....
 
Very well said Nick,

The only thing I can add is when normalizing the steel You should do this about 3 times to make sure the grain is refined.
 
Ok... so here is the senerio... you are forging a blade..... you obviously need it to cool to handle at some point. Since it has been said that we simply dont dump our work in water.... what do you dump it in..... would oil be used here (or the goop.. whatever the case may be...)


Michael
 
Michael, just let it cool to room temp if you want to handle it. If you cool high carbon steel in anything, it may harden depending how hot it is. Nick gave some very good general instructions, be sure to follow them. After a few blades things start to make more sense. Also, there are alot of variations depending on equipment and tools. Everyone settles on a method that works for him. The best thing to do is jump in and make some blades and test them. You will have your own reject box too soon.
 
Hy all,

I'd just like to add some thoughts (from a novice point of view):
* each steel type has it's appropriate quenching medium. Air hardening steels harden in air (ie D2), waterhardening in water, oilhardening in oil (ie 5160),... The difference between these different products is the speed in which they conduct heath (and thus cool your blade, air cools slowly, oil intermediate, water fast). For example: quenching 5160 in water would cool the blade way too fast: your blade will warp and/or crack easily. It's the speed of cooling that's important (imagine you quenching a blade in vermiculite: it would cool very slowly. Because of this, your blade won't harden but will be soft (annealed)).
This all is why it's so important to know what steel you're using (because the heattreat procedure (critical temp and cooling rates) will be different).

*when cooling a bar of steel (in order to handle it while forging) in water, your blade needs to be at critical temp in order to 'harden' (and crack). When holding a steel bar at critical temperature, you'll know the importance of tongs :) . So if you occasionaly cool a bar (at ie 200°c) in water, you won't harm the steel dramatically, but it won't do it any good neither.

Hope this helps,

tim
 
Bruce/Nick,
Should the blade be normalized and/or heat cycled after annealing and grinding or before? I understand that annealing actually promotes grain growth. Thoughts???

Yeah, the three subjects to stay away from are religion, politics and heat treat.
 
Michael: your heart is in the right place, but the questions you ask would take more space to answer than blade fourms has space for. Spend some cash on books, read, fisit a knife maker or two and read some more, then start your own experiments.
Welcome to the frontiers of the forged blade.
 
Michael -- just as I clicked on the reply button, I saw that the previous post was by Ed Fowler. No matter, except that Ed was too modest to say you should buy his book. At least for sure you should if you plan to forge 5160 or 52100, and in general it'll teach you more than most.

My 3+ weeks away has made my brain fuzzier than usual, but I believe steel manufacturers offer some information on quenching for their steel. Nick had it right on the normalizing and annealing, and triple quenching.

You also might check Bruce Evans website -- beknives.com. Bruce has some tutorials you'd probably find helpful, as do many other experienced bladesmiths.

I'd advise you to go into a heavy-duty learning mode before firing up your forge. Thanks to all the information available, there's no need to go thru a lot of the stuff others have learning things the hard way.
 
Originally posted by NickWheeler
Michael-

I won't claim to be any sort of expert on this, but I think I can answer your question.

First off, normalizing is believed to be necessary to refine the grain in the steel after you've forged it and ease up on any stresses in the steel. To do that you take the blade up to just past non-magnetic and then let it air cool.

After normalizing you can anneal the blade. You take it up to non-magnetic (slowly and evenly). Then you stuff the blade in a container of vermiculite or wood ashes where it will cool slowly. After that it should be soft and "stress-free."

After the blade is rough ground and cleaned up, you can harden it... take it up a little past non-magnetic and quench it (either edge quench or quench the whole thing tip down). Any oil is supposed to work. I know Wayne Goddard came up with his "Goddard's Goop" by putting wax in with lard and later hydraulic oil. It will get hard when it's cold and is easy to keep from making a big mess with when you're not using it.

With an oil quench you want to pre-heat the oil to somewhere around 130 degrees, some say a little cooler, some say hotter, but this seems to be a happy medium.

Most knifemaking steels can be quenched in oil. Using water as a quenchant is kind of extreme. I know it's very easy to crack the heck out of a blade by water quenching it. Water quench's seem to give the most pronounced temper line, but that's just from what I've seen personally.

The tempering is done in an oven after the blade has been quenched. Most seem to triple temper their blades by putting them in an oven somewhere between 360-460 degrees for about two hours per shot. You draw some of the hardness back out of the blade this way and make it less brittle.

Again, I am not claiming this to be any sort of be-all/end-all info on this...it's just what I've learned so far.

Good luck,
Nick
Click to expand...

This is a great post. I wanted to double check on a few things. is the order you do this heat treat with fire/oil, then normalize it and then anneal it?

I live in a suburb area and I can't make a pit to heat up a blade, what would you or anyone else suggest I could use instead, I would have to do it in a garage or driveway. Could an evenly placed blow torch be used? Thanks.
 
I live in an apartment and have been playing around with the One Brick Forge. This might be someone that you would be interested in (there is a thread of this close by actually).

Michael
 
<< I live in an apartment and have been playing around with the One Brick Forge. >>

Forging in an apartment? I'll bet the landlord loves that!!!
 
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