Annealing steel

[SPletcher]

OK, working on a flint cock and heated the top section to red then peened flat and reshaped.  Now no matter what I try I can't get it annealed.  I have tried the following

- heated to cherry red and let cool
- heated to cherry red and then directly put into oven preheated to 500° F, and then turned off and let cool

None of these methods worked, any other ideas?

Thanks,

Steve

[Bennypapa]

There are 2 things you need to fully anneal almost any type of steel.
Get it to the right temp then cool it at the right rate.
Depending on the steel, those 2 factors vary.

The biggest problem in small parts such as yours is that their lack of mass allows them to cool rapidly.

I suspect that you have not heated the part hot enough and not cooled it slowly enough. I don't know what equipment you have available to you but good results can be had with charcoal.
You may need to supply air to the fire to get it hot enough. Once you reach temp, if your fire is built in a pit in the ground, bury the part in the coals then bury the fire. This will seal in heat and allow for a slow cooling.

If you are using a torch consider putting the part into a heavier, thicker container like some 1/2 thick square steel tube and pack the container with steel shavings. This container will be harder to heat to temp but will retain heat better than the part alone.

Good luck.

[keweenaw]

Most currently cast lock parts, like plates and cocks, are either 8620 or 4140.  Unless someone specifically hardened the cock for some reason it shouldn't have been very hard to begin with but 4140 is pretty tough and won't cold form all that easily.  Heat that sucker up to a nice bright cherry and immediately stick it in a bucket of wood ashes and cover to the depth of a couple inches.  The wood ashes will insulate it and it will cool very slowly.  Either 8620 or 4140 can be annealed this way.  One can also use stuff like vermiculite as an insulator but I always have some wood ashes around. 

Tom

[Blacksmoke]

Synder has it correct!  I've done that way many times without failure.  You will want to use hot ashes if you can and let the whole thing cool for a number of hours.   Hugh Toenjes

[Stophel]

Do you have scale on the surface?  Maybe that is what is hard.

[D. Taylor Sapergia]

A few years ago, I had a new tumbler that needed to be drilled and tapped 6 x 40 for the hammer screw.  It was hard - even a centre drill wouldn't touch it.  I asked for and got advice from both Cody Tetachuck and Tom Curran who told me the same thing.  So I made a little fire in my yard from birch and got a nice bed of coals.  I took my portable oxy/acetylene  torch outside and heated the tumbler nice and bright, then dropped it into the coals where I covered it and left it until it was cold.  The tumbler now was dead soft.  Prior to this successful annealing, I tried both sand, and ashes, but to no avail.  The slow cool was what worked.

[Dphariss]

There is really no way of knowing the exact alloy. Maybe some old Buick bumper chrome got into the mix.
I would heat it just past cherry red coming to orange and then put in ashes or hot ashes/coals.
If I get desperate in winter I use the wood stove.
Some stuff will air harden and require a real slow cool down as Taylor did.

Dan

[J.D.]

I have to ask the question, why anneal a cock? Cast parts aren't all that hard to begin with, so there really isn't a point to  annealing relatively soft parts; and how do you know it isn't annealed?

That said, since others have suggested their pet ways of annealing small parts, I'll share mine. Make a bed of charcoal briquettes, lay your part on top, cover with a layer of briquettes, then light 'er up. 

For smaller parts like springs, only a few briquettes are necessary. For small springs, just one briquette will often work.

God bless

[Dphariss]

I have to ask the question, why anneal a cock? Cast parts aren't all that hard to begin with, so there really isn't a point to  annealing relatively soft parts; and how do you know it isn't annealed?

That said, since others have suggested their pet ways of annealing small parts, I'll share mine. Make a bed of charcoal briquettes, lay your part on top, cover with a layer of briquettes, then light 'er up. 

For smaller parts like springs, only a few briquettes are necessary. For small springs, just one briquette will often work.

God bless

He heated it to do some gunsmithing and it was then hard.

Cocks are subject to a lot of shock and might snap off in normal use.

Its very difficult to file/polish hard parts.

Soft parts are much easier to engrave.

There are many reasons to anneal parts.

Dan

[SPletcher]

Thanks guys, I will try the ash method then if that fails I will try Taylor's method of throwing into a fire.

[J.D.]

I have to ask the question, why anneal a cock? Cast parts aren't all that hard to begin with, so there really isn't a point to  annealing relatively soft parts; and how do you know it isn't annealed?

That said, since others have suggested their pet ways of annealing small parts, I'll share mine. Make a bed of charcoal briquettes, lay your part on top, cover with a layer of briquettes, then light 'er up. 

For smaller parts like springs, only a few briquettes are necessary. For small springs, just one briquette will often work.

God bless

He heated it to do some gunsmithing and it was then hard.

Cocks are subject to a lot of shock and might snap off in normal use.

Its very difficult to file/polish hard parts.

Soft parts are much easier to engrave.

There are many reasons to anneal parts.

Dan

Yes, I understand all of that, however, I have never encountered a cock that hardened when heated to bend it, though I haven't bent all that many cocks.

Most cast lock parts are something approaching 8260, which shouldn't air harden. Even 4140 parts shouldn't air harden, so I'm wondering how that cock hardened, unless it's made of some mystery,air hardening  alloy.

Either way, slow heat to critical temp and slow, slow, slow cool down is the key to annealing these parts.

God bless

[JCKelly]

One can occasionally run across some very interesting alloys in an investment casting. It depends upon what alloy the foundry melted for the job before the 4140. If it was a tool steel, or maybe stainless. some of the alloying elements tend to remain in the furnace refractory & really juice up that 4140.

I recall a mining tool company once that ordered cast widgits, into which were to be brazed carbide bits, the widgits intended to be some tool steel. But the foundry had cast stainless just before & did not use a "wash heat" before this job. Mining Company ended up with some nice high alloy, low carbon steel widgits. I worked up a carburizing schedule for them, which some not-to-be named manager at Nameless Company presented as his idea. The mining company loved the results, their case-hardened non-standard steel far outlasted what they'd used before. Company communications being what they were/are, I doubt they ever learned to adopt something like this new alloy.

Anyway, if the guys says its hard, its very likely hard, regardless of what 4140 Is Supposed to Do. Get it red hot & cool over a long time in hot ashes, coals, vermiculite even, as these assorted replies say.