Anneal didn't work.

D

DustinHall

Joined
Dec 31, 2008
Messages
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I had a large blade made of O1 that was hardened and tempered but got broke so yesterday I ground out a smaller knife from it then stuck it in the forge to anneal it so I could drill holes. Anyway, got it up to non-magnetic and buried it in kitty litter and waited for it to cool. A few hours later I took it out and tried to drill my holes but, the bits wouldn't even phase the steel. It's still hard! How can this be? :confused:
 
What was the air temp that day? It might have cooled too quickly to fully anneal. Was there a layer of decarb?
 
Our standard practice for annealing O-1 is to heat it to 1400/1450F and furnace cool it at no more than 25F per hour. Cooling in kitty litter or even a small pan of vermiculite will probably make it harder.
 
O-1 will air harden.
To soften it for reworking, it's best to spherodize it. Bring it up
1250-1300 and hold for an hour, and then slow cool.
If you don't have tamp control to hold at 1250-1300, heat in the
forge to dull red (still magnetic) and air cool to room temp...repeat
as necessary
 
Something that has worked for me is to sandwich the blade steel between two large pieces of mild steel. Heat like you did before and put in the kitty litter. this will slow the rate of cooling, and anneal the blade.
 
I should have mentioned I only have a coal forge to do my heating so holding at 1300 for an hour is not really possible nor is cooling at a specific rate of 25f per hour. I did not know O1 could air harden at all, I thought that even with my set up and process, the steel would/could get soft enough to work by just bringing it to non-magnetic and letting it cool. I've done it before like this but, this is the first time this has happened. It was kind of chilly last night.. 50s but, still, it should have gotten soft enough even if not fully annealed. I appreciate the replies. I will try doing what you suggested Russ and hopefully it works. I was also thinking of heating it up to non-magnetic, air cooling, then bringing it up to just below non-magnetic and then shutting the forge down and just leaving it in there until it cools which takes several hours. If that doesn't work, I don't know what else I can do. Thanks again guys.

Interesting, Tom. Might have to try that. How do you keep it sandwiched together though?
 
Perlite or vermiculite from your lawn and garden center will hold the heat better, in my opinion. I also agree that you should heat some scrap steel along with the O1, although I've just put them into the perlite with the steel, not sandwiched. Leave the steel in over night and don't bother thinking about it.
 
If all you have is a forge, you really shouldn't work with 01 at all. I hope that doesn't sound harsh, but 01 is just not forge friendly for any HT operations, including annealing.
 
Thanks for all the input. I understand I most likely can not achieve maximum potential from O1 with my simple forge and would be better off with something like 1084 but, it is what I have on hand atm and I get satisfactory results with my methods even though I know they could be better. I also understand that vermiculite or perlite would be a better choice than kitty litter but, again, it's what I have on hand. I'll be upgrading soon.
Right now it's in the forge cooling slowly so we'll see if it worked this time around.
 
I think it cost me less than $10 for two decent sized bags of it at Wal-Mart. The time and fuel used probably already paid for it. That's just how I see things, always more than one way to skin a cat. Good luck with the knife.
 
Oh yeah, getting the right stuff is always worth it. I'm wondering now, how much vermiculite will I want? ...how much should be surrounding the blade to keep it well insulated I guess is what I'm asking? And is one better than the other, perlite or vermiculite? Thanks Acrid.
 
people, O1 is a hypereutectoid steel with serious alloying to keep it from forming pearlite, a lamellar anneal (i.e. heating above non-magnetic and slow cooling) just will not work so well. So going from wood ash or kitty litter, to vermiculite or any other pile of insulation is NOT going to work! Even if you manage to force this steel to make pearlite the proeutectoid carbide will sheet out and still laugh at every saw blade, drill bit or file you have!

It is not how about how you cool it it is about how hot you get it and what temp you allow it to cool from. If you engage the divorced eutectoid reaction or keep proper solution from occurring you could quench the darned stuff and still get it soft.

Normalize with the first heats being well above non magnetic and follow this up with several cycles that are dull red but never nonmagnetic and forget about the vermiculite, wood ash or kitty litter and the steel will be soft. If you want large spheroidal carbide in a dead soft ferritic matrix you can use a controlled oven and make the steel into butter. But if you just want to be able to work it a forge will do all right so long as you keep it below non-magnetic.

There is no such thing a a one size fits all heat treatment, and as long as blade makers approach things like there is there will be these kinds of frustrations. If it has over .8% carbon spheroidize it and leave the slow cool from critical to the eutectoid and below.
 
Kevin, I appreciate you taking the time to stop in and share your knowledge with me/us on this topic. I did almost what you said needs to be done (normalized twice then heated below non-magnetic then let cool) without really knowing what I'm doing but, thanks to you, I can understand a little more about the science behind why my first attempt to anneal did not work. :thumbup:
 
Read those stickies guys; thats why they are on here.

Kevin, you posses an ungainly amount of patience.


Fred
 
Alright.. I tried what you said kevin... normalized several times then brought it to dull red several times and it's still un-drillable. I'm lost. :mad:
 
I'm thinking you're right Arthur. I just don't get why I can't get the steel soft even after trying what Kevin said would work. I'da figured even bringing to nonmagnetic and air cooling would soften it enough to dril but, nope, it's still just as hard as when I ht'd it.
 
Whenever you seem to be dealing with any steel that work hardens or air hardens, always try a sub critical anneal ( as Kevin said).

Your drill bits may be burned up by trying to drill hard steel. Sharp new ones should help.
Carbide bits take a little skill to drill with, so read up on using carbide drills ( they are not unbreakable super drills). Drilling the wrong way with a carbide bit will break a $10 drill bit in seconds.

The next thing to consider is the possibility that you have a piece of steel that is not O-1. Steel gets mixed up by accident in your shop as well as by the supplier. A good practice is to label all steel with a metal marker on both sides of both ends when it arrives. Re-label it every time you cut some off.

Stacy
 
bladsmth said:
Whenever you seem to be dealing with any steel that work hardens or air hardens, always try a sub critical anneal ( as Kevin said).

Your drill bits may be burned up by trying to drill hard steel. Sharp new ones should help.
Carbide bits take a little skill to drill with, so read up on using carbide drills ( they are not unbreakable super drills). Drilling the wrong way with a carbide bit will break a $10 drill bit in seconds.

The next thing to consider is the possibility that you have a piece of steel that is not O-1. Steel gets mixed up by accident in your shop as well as by the supplier. A good practice is to label all steel with a metal marker on both sides of both ends when it arrives. Re-label it every time you cut some off.

Stacy
Click to expand...

It is a possibility my drill bits suck. Actually, they do suck so maybe I need to get some new ones. I'll read up on the carbides.
I know for sure the steel is O1. Thanks Stacy.
 
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