For the purpose of this thread the subject matter is not whether we heat treat anything but to be specific about the terms and what they mean

1. Heat treating: any process (in this case dealing with steels but in reality with anything at all) that changes the grain size, structure, or molecular content of a steel is heat treating
A. Therefore carburizing is heat treating
B. annealing is heat treating
C. hardening is heat treating
E. Tempering/Drawing is heat treating

2. Carburizing: The adding of carbon to the surface of steels. Usually by osmosis using a hi carbon salt bath or natural gas environment. Can also be accomplished with leather and ground bones. Typically 1550 deg F is used to do this

Since the presence of carbon is necessary to the "hardening" process we need to carburize low carbon steels to allow any hardening. Since the exposure to high carbon atmospheres will allow carbon to penetrate steels at about the rate of .010 the first hour and about .005 the ensuing hours. This actually alows case hardening as only the outer case of steel has enough carbon to produce "martinsite" (hardened steel)

3. Annealing: The process of allowing (nearly) all the grains of metal to return to austinite (very large and soft grains of steel. Typically accomplished by taking the metal to 1550 deg and slowly cooling over the course of many hours.....possibly even a day.

4. Hardening: The process of turning (nearly) all the grain structure (with enough carbon to allow the transformation) to Martinsite. This is a dense and small grain size that resists penetration (the definition of hardness). Once the martinsite is formed the steel is quenched in oil or water or brine. This allows the metal to return to room temperature but so quickly that the martinsite cannot change back to austinite as it takes a little time for this change to happen.

4. Drawing (Tempering): The reheating of a hardened steel to a lower temperature than the temp required to produce martinsite and holding for a time to allow the grain structure to soften a little. The time and temp of the draw controlls the final hardness of the product.


I see we fumble with the heat treat issue a little and in some manner it's due to terminology....I hope this helps correct it a bit.

All I want to know is...is the test going to be multiple choice...do you grade on a curve...and do we get extra credit for creative answers even if they’re wrong?

great post

so, let's say that all those terms are aspects of the "generic" heat treating functions..

but "heat treating" an action is actually the series of steps


jeffe

quote:

but "heat treating" an action is actually the series of steps

Heat treating a Mauser action that has low carbon steel typically is the process of full annealing, carburizing, hardening, and drawing.

It's actually many steps and is scientific as hell and complicated.....but it's simply case hardening (not to be confused with color case) and drawing to prevent brittleness.

Metals do not have molecules .They have atoms , crystals, grains....Annealing first transforms steel to austenite then on cooling to pearlite or spherodized structure....Hardening -austenite on quenching transforms to martensite....Carburizing puts carbon into the steel by diffusion not osmisis....I'm a metallurgist , "scientific as hell".

1) Heat treating is, as others point out, a sequence of procedures. It may include several of the steps or procedures discussed in the post.

2) Yes, diffusion is the mechanism by which carbon migrates into or out of steel at temperature.

3) The physical chemists would describe the alloys we deal with as "solid solutions." There are well understood (but complicated) phase diagrams describing the behaviour of specific alloys and the composition of the crystal matrix that result from elevation to specific temperatures and quenching. These can often be found fo0r the alloys of interest in the "Heat Treater's Guide."

This is a fascinating area of complex science. Some consistency of terminology is desirable. It was necessary to develop common nomenclature as it assists the communication of knowledgeable folks.

It is helpful if the nomenclature we use is aligned with the standard practice of the field of technology being discussed.

LMAO!!!!!!! Ok Vapodog. I can live with that but you left out perlite steels. By the way what would you do if you ran into a great sluth of Ursus Americanus while strolling through the Acer Rubrum. By the way did I mention that I’m a poo head?: Rod Henrickson

Vapodog,
Heat treating is a different process than carburizing if you are taking to the folks who do it for a living. If you are talking about any process that changes the structure and uses heat then rust bluing is heat treating.

I should have done that internet search before I posted. The first one I found included color case hardening which is in effect carburizing. I stand corrected. Actually, rather standing, slumped and looking sheepishly, corrected would be a better term.

I don’t never really talk like this but I got poo poed for vulgar poo pooing so read betwixed the lines! Rod Henrickson

Ah Mete I just read your post! Metallic atoms as we know can not be formed into molecules as I was taught in high school. But that is only as we know. Right now there is an exception. The atomic race proved that a Beryllium atom can be bonded to another Beryllium atom. We just are not sure if Beryllium is a metal at all. We know that it is highly unstable and can produce a great deal of energy but hydrogen can produce a lot of energy and we used to think it was a metal too. It is still classed as a metal in current periodic tables but it isn’t a metal at all! If you don’t believe me look at your latest periodic table. There is lots of poo in the world and I try to spread my fair share.

Rod Henrickson :I have never been wrong I’ve merely found 10,000 ways that don’t pooing work!

If I recall my high school metal shop teacher‘s words correctly heat treating metal is any process where the metal is brought to a certain TEMPERATURE...for a certain TIME...and the heat is removed in a controlled manner which results in some TRANSFORMATION of the metal. He called it the “Three T’s.â€

Customsox,

Pardon my vulgar use of the term.

This goes back a couple of years so spare me if I am a little fuzzy on the details. I don't have immediate access to my notes on what transpired on my 1909, but working from memory we hardened the surface to a depth, I want to say 30-40 thousnads, and it was done to a RC scale of 38 (?). I did a bunch of homework on it before I had it done, but like I said its been 5 years or so and I am a working engineer and have a FIFO method of keeping numbers in my head, I have an excellent memory but you wouldn't beleive all the numbers I have to remember and process in a week, so don't take those numbers to the bank.

I had a ton of work tied up in the 09 action when I had the issue, and was real concerned about warpage as it had the potential to have more money tied up in it, and end up as scrap metal.

In my vulgar use of the term, its still heat treating, no not like on a tool steel, but the still a process to harden steel.

You are correct though on 09's just treating the low carbon steel like I would on a higher carbon steel would be a net gain of zip, carbon needs to be added. as I recall there is a limitation on how deep this can be done, and I certainly remember that being too hard on the RC scale makes it brittle, which is actually worse than soft, as it becomes a safety issue.

Once I had it sorted out what needed to be done I shipped it off to someone who actually knew what he was doing. The only positive note was I had a couple of pre war actions done at the same time, when done in multiples the cost comes way down on piece price.

Ok for you guys with more knowlege than me regarding carburizing. This is what was happening and the LONG way I finally figured it out.

We are making springs from 1018 steel. Have been for most of a decade now. By carburizing the metal and drawing it back you can create a spring. RC 42 to 45 harndess.

What we ran into from time to time was enbrittlement at a latter date, 18 to 24 months.

So talked to two heat treaters, these guys have been doing all types of steel for a long time. All they could come up with was increase the draw temp and duration. So that helped but still geting some breakage but not as much as before.

So went to a old friend over in Richland WA. area, sent some samples and really made him think about it.

What he come up with , since we are carburizing in a some what controled furnace. A steel retort with wood charcoal in it surrounding the parts. Our soak temp is 1625 Degrees F.

WE do not have total control over the amount of the carbon that is introduced into the part. Since steel is highly fluid at these temps. The part was soaking far more carbon than needed. Thus changing the grain structure from the smaller steel, to a larger CAST IRON structure.
Also we are inroducing Hrydogen into the part thus getting the long term breakage of the part.

So to get away of this, we have reduced the amount of soak and increased the draw temps. also added another second draw.

Problem solved.

But this is something that you will not find in most books, and most heat treaters will not think about it because of the types of furnaces they are using they do not have this problem.

Jim Wisner
Custom Metalsmith

Jim,

On a total hijack question are you doing floorplates for FN mausers?

schromf,
Your "vulgar" use of the term" was accurate, mine was not. In my post above yours, the first paragraph was posted. I then did some reasearch and posted the next. Aplogies to you for my reaction.

BTW, we are in the same boat as far as processing numbers. Engineer here also, civil consulting type. Well not so civil on my response to you.

Customsox,

Yeah it became immediatly apparent we were argueing the over the same thing.

Whatever its called its still a good idea to get it done on old mausers, especailly when Mike plans to chamber it in a 376 Steyr. Bore diameter is his favor but that short fat case looks like a high pressure round to me, something like a 338 Win Mag around 64000 cup.
He has a few techical details to sort out on this project I think, pressure and feeding issues come immediatly to mind.

When I send a knife blade to Paul Bos for heat treating, and tell him what kind of steel it is, and that I want it drawn to Rc 59, he sure knows what to do with the blade, and all of the steps to do that heat treatment.
I would expect to be able to tell the folks at a place that heat treats rifle actions to "do your thing", and they'd know exactly what to do.
Maybe I came in in the middle of the movie...???
What's the point in all of this?
Don

All,

I'm very interested in understanding this, and I appreciate all the posts here and on the other heat-treating threads.

What I still don't understand is why re-heat treating doesn't work? Why can't the early number Springfields be completely annealed and then completely rehardened?

And, if you're going to send off your old Mauser to be re-heat treated, then do you still need to worry about annealing the bridge of the action before drilling and tapping it? (I know, nobody else breaks their drill bits while trying to drill and tap, but I've managed to).

Or do you really need to slather heat control paste on the bolt and put in the heat sink while welding on a new bolt handle? I imagine it's a good idea to avoid warpage if nothing else, but why doesn't the annealing and re-heating take care of all this?

Thanks,

Steve

quote:

Originally posted by DMB:
When I send a knife blade to Paul Bos for heat treating, and tell him what kind of steel it is, and that I want it drawn to Rc 59, he sure knows what to do with the blade, and all of the steps to do that heat treatment.
I would expect to be able to tell the folks at a place that heat treats rifle actions to "do your thing", and they'd know exactly what to do.
Maybe I came in in the middle of the movie...???
What's the point in all of this?
Don

If you went to any company that does case hardening and told them that you action was 1020 steel and you wanted it carburized .03 deep and hardened and drawn to 36-40 Rc it's likely that they could do that. However to keep it from warping in the process is another matter.

quote:

Originally posted by skl1:
All,

What I still don't understand is why re-heat treating doesn't work? Why can't the early number Springfields be completely annealed and then completely rehardened?

Steve

IMO they should be capable of being full annealed and rehardened assuming the metals in the action have not been damaged by historic attempts to do so. From what I've read the hardening process of the 1903 era was less than scientific.....folks looking at it and saying...."looks good to me"

From my own personal experience, the attempt to repeatedly heattreat a piece of steel leads to deterioration of geometry and general integrity of the steel.....you might wind up with a lot of money thrown in the scrap can.

From what I've read about the history of the early Springfields, the pronlem was to a small number of units and the attempts to correct it was of questionable science.

Personally, if I really wanted to use an early numbered Springfield, I'd use it as-is or trade it for something I can use. The economics of the repair makes the question purely academic IMO

JWisner,

What you were seeing is grain growth ... doesn't necessarily mean that the carbon content dropped. Typically reducing the soak time or grain refinement will handle this. Grain refinement involves taking the material to above the critical temperature and quenching. Then taking the material to just below the critical temperature and quenching (twice). This will yield fine grain material.

The extra draw cycles (and the use of the term "draw" here has been replaced by "tempering" in the now common use ... don't like it, but that's what other folks use now) will lower the hardness progressively.

Trick is to get a material with the correct hardness, center gummy-ness, and small grain size.

Takes some experimentation as you have noted. Sounds like you found a path that yields a good product.

(This is neat stuff. We use computer controlled molten salt pots to HT blades. Provides very precise control of temperature. Kinda exciting at times )

Vapodog thats a pooing good question! When i went to school at CST in denver they told us that the steel in those actions had been taken to high in heat treatment and that the steel had been burned. Now I have never understood that. Mind you up untill now I've never asked color me pooing stupid! They were suposed to be double heat treated steel and i know what that means and how its done. But how the poo do you burn pooing steel? Rod Henrickson I think its me?

If steel is taken well beyong the critical temperature and held too long, carbon can migrate out of the metal ... and grain growth can occur. Really big grained material breaks more easily than small grained material.

Remember that the early range of Springfields were HT'd by eyeball. Notoriously inaccurate way to estimate temperature.

So it's carbon deprivation from repeated or improperly done heat treatment, right?

So I still need to be a little worried about annealing my action with a torch so I can drill and tap it.

Steve

When I attended CST they wouldn't let me in the heat treating class ! If the steel has been overheated to a high enough temperature things happen in the grain boundaries [things tend to collect there] that are irreversible .Thus they can't be reHTed .So it's not the carbon which always could be replaced. Annealing with a torch is not going to remove any carbon.

Thanks.

Steve

mstarling,
Interesting set up you have for heat treating blades!!!
One of the things that's important for me is to get the blades back straight, so I don't have to fool with the torch. Saves me a lot of time.
It would be neat to see your heat treating operation sometime, except I hibernated about 10 years ago, and now am glued to Grayling...
Take care,
Don

Go back it's a trap!

DMB,

We use two pots ... one with 50% NaCl and 50% CaCl2 ... the other with nitrate/nitrite blueing salts. Both pots have PID controllers running Ron Reill's venturi burners to maintain temperature to +-2 degrees.

High temperature molten salt is really scary ... it is self incandescing and has a viscosity lower than water. My first thought was a Cobra ready to strike ... and I hate snakes!

For very thin stainless blades, we take them out of the low pot and clamp them between two thick steel flats. Has worked remarkably well. We seldom make thin carbon steel blades.

There are pictures and diagrams of the HT setup on the web site. http://www.mstarling.com

So what's with Grayling? If it's at all like the Charleston area ... it's a nice place to live. Rural with good hunting.

Mike,

Thanks for the information.. Much appreciated.
I like that idea of clamping the blades between two pieces of steel to keep them straight.
I retired from my regular job 10 years ago down in Detroit, and moved up here to Grayling right after that. I'm 71 now and kind of stuck in Grayling.. Inertia.. That's what I meant about being glued here. Just getting old, ornery and lazy. Otherwise, I'd drive down and visit you, just to chat.
Grayling is 200 miles north of Detroit and has all of the hunting and fishing anyone could want in this part of the country. The town is only 2000 strong.. Small, which I like.
I only make a few knives anymore. Nothing to sell, just to keep tuned up. I decided back in the early 1980's that I wasn't going to get into heat treating blades as I had a full time job, and wanted to grind blades and do the finishing, which I like a lot. But, not spend time with heat treating. I had a place in Detroit do the blades for a long time, but too many blades came back bent. Just got tired of straightening them, so I found Paul Bos at the time, and have sent them to him ever since. He's a class act. Every blade comes back clean and straight, no matter whether it's a stainless blade like ATS-34, D-2, or O-1 which is a carbon steel with no chrome in it. No black scale or anything like that. So, it saves me time in putting them together.
Take care,

Don Buckbee

I too think Paul is about as good as it gets for SS HT. Bob Grind used Paul for all his stuff. I could not make enough blades to get a reasonable price from Paul directly when Bob passed away. So ... we figured out how to do it ourselves.

De Holder in Arizona also does singles and small volume work at a reasonable price ... but I think he may go just a little too hard. He uses an electric furnace as does Paul and the blades come back with that purple color ;>

We really like ATS, S30V, and 440V at RC 59 with a cryogenic soak ... impressive to see a blade hold that kind of an edge and yet be flexible rather than be brittle. We also like L6 and L6/1084 damascus done to bainite. Amazing to see a blade bent to 90 degrees without the edge chipping! Salt pots deliver almost as nice a surface after HT as an inert atmosphere electric furnace ... not quite, but close.

Enjoy the hobby and take very good care.

quote:

Originally posted by Rusty:
Go back it's a trap!

it's a trick.. get an axe...

Mike,
Thanks for the info..
Hang in there...
Don