Annealing cold rolled

[longcruise]

So I have some hardware store flat stock cold rolled steel that I plan to use for barrel keys.  Google searches leave me a little uncertain.  It is suggested that 550 to 700 degrees will anneal it.  Is this correct?  I can probably hammer and file these out as is but would be nice to make it a bit easier.

[longcruise]

Ok, a more attentive reading shows that the temperatures are centigrade.

[Bob Roller]

So I have some hardware store flat stock cold rolled steel that I plan to use for barrel keys.  Google searches leave me a little uncertain.  It is suggested that 550 to 700 degrees will anneal it.  Is this correct?  I can probably hammer and file these out as is but would be nice to make it a bit easier.

Only God knows what that steel might be. If it must be annealed it has to be hardened.
Bob Roller

[D. Taylor Sapergia]

Hardware store flat stock is generally mild steel.  It cannot be hardened so does not need annealing.  To be sure, take a small piece, heat it bright red, drop it into water, and check it with a file.  It will still be dead soft.  If it were high carbon steel, it would be glass hard.  THAT will require annealing.

[rich pierce]

Your mileage may vary. I rarely find cold rolled sheet steel to be dead soft. It feels like the rolling process work hardens it. I don’t find the same with hardware store flat stock 1/8” or thicker.

[longcruise]

I put the needed pieces on top of a full fill of a charcoal starting tower.  Should be cool in a couple hours.  I'll compare it to the stock it was cut from to see if there is a noticeable difference.

[Ross Dillion]

I’ll agree with Mr Roller on this one. Usually I refrain from commenting on this topic because it always seems to hurt someone’s feelings. When I read of people “hardening” mild steel all I can do is shake my head. Cold-rolled is a different process but it is mild steel. The stuff I buy at the hardware store is hot roll or HRPO. If in doubt look at the price.  High carbon tool steel is expensive.

[44-henry]

Because it is cold rolled it has s lot of internal stress and does benefit from a normalizing operation, but for small parts it probably won't make much difference, larger pieces however will likely warp after machining/shaping.

[Ross Dillion]

For making barrel keys I’d find whatever hot roll comes closest to the finished dimensions. There’s really no benefit that I can see to using cold rolled since your gonna file it to shape anyway. 

[Mauser06]

Can't really help but I made my first trigger a couple months ago. 


Used sheet steel from the hardware store.  I think 1/16"? 


Anyways....to pound out the trigger itself (I think shoe is the right terminology...the part your finger touches..) I found it formed much better once I put the torch to it.   It was thin and I was able to use a regular old propane torch. 


I figured the same...it's not hardenable steel....but was worked hard when it was formed to sheet steel.


Think I found a tutorial here on making a trigger....I never would have imagined I could pound it out of thin sheet steel.  But it worked...and was rather easy to do. 

[Rolf]

When pounding out trigger shoes from mild steel , I allways aneel at 600 celsius 2-3 times. If I don't cracks develop around the edges of the shoe.

best regards
Rolf

[flehto]

I was fortunate in that I found a large sheet of steel  press stock while waking across a street. It was .100 thick and has been made into wedges, keys, triggers,  trigger plates and front sight blades. It's quite soft  and has never work hardened when cold peening triggers and wedges. Tried to harden w/ a bright  red color and water quench and it stayed soft.

Seeing this was press stock to make parts in a stamping die, the quality must be better than run of the mill cold rolled steel. As was  said, cold rolled steel has a lot of stresses due to the cold rolled process and requires normalizing. Also if only some of the surfaces are machined on a large piece of flat stock, a lot of warpage  will result. Low carbon hot rolled steel is much more stable but requires surface grinding  if jigs and fixtures are made from it.....Fred

[Ross Dillion]

Lucky find! Must be what we referred to as draw quality steel or something like that. It’s been awhile since I was employed in metal fab. We didn’t use this material very often. Evidently it was expensive. 

[Bill Raby]

Mild steel won't get any harder from heat, but it will get work hardened. Any metal does.

[JCKelly]

Most small piece of steel one buys (local hardware, Home Depot, Lowes, &c) have been cold rolled to shape. Should have a white/metallic color and smooth surface. You can use it as-is. If you want it softer, to work more easily, heat it with a torch to a nice red and set it on the floor to cool.
If you have a furnace that would be about 1350-1400F (700 - 760C). Do not quench it (probably doesn't matter anyhow if it is mild steel from the hardware), no need to pack it in anything for a really slow cool.

Steel is usually HOT rolled to plate, bar or strip. HOT because it is softer, easier to roll. When it comes off the mill it has a black (oxide) finish & the surface is not perfectly smooth. For most small stuff this hot rolled steel is then rolled "cold" to its final shape. Better finish & better tolerances than hot rolled.

"Hot" means the steel mill heated it to a glowing red before they started to roll it.
"Cold" means they didn't heat it, though just the heat it works up from all that "cold" work will be enuff to burn your fingers. 

Your P.I.T.A. Metallurgist, Jim Kelly

[longcruise]

Everything I read about it suggested that cold rolled was a bit harder than hot rolled. 

So this morning I did a quick file test to compare the pieces that were subjected to the charcoal chimney with the original piece.   A few cuts with the file didn't indicate any noticeable difference.  I went Ahead and made a set of keys with the pieces that got the heat treatment.  Results were very satisfying.  These were for a GPR that was missing the keys.  Track sells them but this made for a fun project.

Tomorrow I'll make a few more from the unheated stuff and see if there is any difference in workability.

[Goo]

I think you should consider "metals Depot dot com" or speedy metals dot com prices aren't bad and they tell you what they are selling you . 

[Dphariss]

So I have some hardware store flat stock cold rolled steel that I plan to use for barrel keys.  Google searches leave me a little uncertain.  It is suggested that 550 to 700 degrees will anneal it.  Is this correct?  I can probably hammer and file these out as is but would be nice to make it a bit easier.

Why bother? A meaningful anneal will need a much higher temp but it would be a waste. It will likely file better as is. If you need to form heads then heat the end you intend to hammer.
Dan