doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Color Case Hardening - 2

Yikes. Didn't really intend for this thread to become quite so heated! (forgive the pun).

Actually all interesting stuff. It's fair to say what I am doing is surface colouring. However, due to the fact that my annealing is for 1hr also I think that's why I'm not so phased with warpage...I'm not going deep at all.

T

I think you are correct Tony.
The conditions you have suggested you are working at wouldn't seem to promote deep carbon migration.

Why don't you case a piece of 1020 an inch thick or so, and then cut it in half with a grinder? Bandsaw would toast the blade.
Then you could see with a loop how far in the carbon specks have migrated. Just for fun.

Nice idea I've actually got a square piece I put as a water displacer ahead of the parts..actually...hmm its still at the bottom of the tank...cheers

Wow, leave for a little while and come back to the set of the family feud

Thought we were having a decent discussion about Case hardening…so what happened?

Bottom line is that Case Hardening is really not voodoo, hasn’t been for a bunch of years.

Back when I first started CCH, those who knew how to do it…wouldn’t talk about it; and those who thought they knew…would tell you a bunch of crap.

That’s about when I started building my “Library”. I bought every period (1890-1920) book on case hardening/heat treatment of steel that I could find. I’ve got over a dozen books on the subject. Back then case hardening was a well understood process. Lots of research/data into depth of case correlation with carburizing temp /time /materials.

When carbon rich materials (in our case Wood/Bone charcoal) are heated, they begin to off gas carbon in the form of carbon monoxide and carbon dioxide. When steel is heated, it will absorb this carbon. Steel will begin to absorb carbon well below its critical temps, and can be hardened when quenched below its critical temp.

To me, the true “mystery/voodoo” is in the colors, Winchester v. Colt, Marlin, L.C.Smith, Parker, etc

V/r

Mike

Mike...

There are just so many people in this hobby that just don't understand this, of course all of them have never actually hardened a piece of steel........they probably never will and love to argue numbers and inject negatives....with a firm belief that we are somehow structurally weakening old gun receivers......and making them brittle, the most common phrase you hear from the uninformed.....

I don't think I have ever heard of an action that failed from bone/charcoal "re-casing"--(not counting the 'El Torcho method')--, there may be some out there done poorly and over heated that failed, I am just not aware of any in my travels......as long as the temperatures are kept within the envelope, the risk is held to a minimum IMO....

So, from a safty standpoint......there are many, many more shotgun barrel failures that are the result of grinding out the chambers and forcing cones and bores by the "barrel butchers" who actually remove lots of metal in different places.........IMO........

CZ...

"Well, what about the action that was repeatedly heat treated"...?....."It would take hours and hours to add a slight increase in depth from the prior state"..........

Very correct......at the temperatures we operate I think it would take quite a few re-casings before the molecular anatomy of an old gun receiver was destroyed.....and as you previously mentioned...most guns receive 'maybe one' re-case in their entire lifetime......

Best,

Mike, indeed!

Actually the thing is for me is that I get very excited about learning something new. My friends often think I'm a bit mad...I'm the guy that pulls out the 1911 20 bore at a clay shooting competition and shoots 20 out of 50 and people snigger...I don't care! I thoroughly enjoyed shooting that little gun. I had restored it and I loved doing it...I've got mates that won't pull out a gun because they might get laughed at with their score...how can one possibly learn if you don't try?

Anyway..I've researched and will continue to learn from people here Like doug, Mike, CZ and others...bring it on...I only hope people can see I'm trying to enthuse my passion...even though it might make some cringe..

Regards,
T

Tony:

And VERY WELL SAID....!........The people that don't take risks are the ones that stay "on the ground"........

Best Regards and Keep It Up Mate.......!.....

Cheers Doug. Actually sometimes people have some authority to taking a W.W. Greener and trying it first. That was a mistake...but hey...I've learnt from it and I've literally just turned of the kiln that is annealing the last of the parts. I'm meeting Graham Greener on Friday at the CLA fair here because he's been super helpful with the dating and how things should look...now if he says it's looking good I've GOT to be happy.

Doug thanks for the continued learned statements:)

T

Doug;
I relly don't know why you even thought I was making a personal attack on "Your" work, I did not intend to come across that way. I did indeed read that post & the depth you said you acheived. Now 1.2-1.5 mm depth is indeed good depth. I was in fact hoping you would come in & give us some more detail as to just how you acheived this. Also if perhaps with the connections you had if you had by any chance had an original part tested as to what was there before anything was done.
As you said I have no idea from what temperature you quench to acheive this depth of case. All I have ever seen on the subject is that in order for a low carbon steel to absorb the carbon it has to be above its critical temperature & that to harden any steel has to be quenched from above that temp. As it absorbs the carbon & the case acquires a higher % the critical temp is lowered. Now I have read accounts that "Some" doing color casing drop the temp prior to quenching, which supposedly assists in prevention of warping. Note I did not say you did this, or actually even state it was an improper method. I simply asked the Question "If" this would in fact result in hardening of the entire case or if it would only give hardeness to a very superficial layer of it.
I still want to know the answer to that. As the process adds the carbon from exposure to its surface it makes sense to me that the deeper into the case you go the lower the % of carbon will be.
I am thorughly convinced that re-casing a gun frame is a job that needs to be done "Right" or not done at all. Nota Bene (Note Well) I am not accusing yours of not being Right.
From your posts on this I felt you could likely answer some of my concerns, but rather than attemt it you just chose to make a personal attack on me. I Pounced Back, for this I do appoligize. Perhaps we can still act like men & have a meaningful discussion on this from which All can benefit.

No apology necessary Miller, thank you though sir.....like the Bible passages we all interpret words differently and I am sure I misread your postings.....?.........I took it as a personal attack (which appears all to common on this BBS) connected to Nitro's smart remarks.....probably my error......and my apology is probably more in order than yours.....so you have it.....

If you take a piece of low carbon steel (at or less than .03wt%C) and pack it in a rich solid carbon atmosphere of your choice and heat for a few hours you will easily attain a carbon depth hardness of about 1 mm.......so from there you, Miller, can work out what is necessary for a slight increase in dept.....

I think the original factories ran CCH at higher temperatures than most of us re-case today, key word here is re-case, therefore the original carbon depth already exists at about 1.2 mm or a little more IMO......I personally do not lower my temps prior to quench and find a lowering of temperature would be detremental to the whole process.....also detremental and key is to lower the crucible and drop the parts into the quench at the shortest possible drop height as the 02 rich atmosphere directly impacts carbon and colors........this is also another reason that I do not lower the temperature prior to quench......and have built special crucibles with an emphisis on this step..........the more 02 in the quench water the better.........

If time, temperatures and various mixtures of solid carbon rich additives are all monitered carefully, some very vibrant colors and uniform hardness can be achieved.....since most of us do not have extreme annealing times, most of the original carbon has not been removed IMO....of course, should you anneal for far too long, then most of the carbon would out gas as a result.....

Most of us keep records and know all our times, mixtures, temperatures and various patterns which satisfy the end result.........various experiments are tried to achieve different colors, but remember, each alloy of steel is different from manufacturer to manufacturer , what works for one, may not work for another....(records, records and more records)...and these alloys also can change from year to year even with the same manufacturer, CCH has and always will be like a snowflake....no two are alike............. this is truly the beauty and fasination of CCH for me........

Consistency on the hardness issue must be and is very consistent on re-cased items in my opinion.....some people I know heat small parts and quench these in a carbon rich medium, like various cyanide compounds........I personally do not like that process or the colors it achieves......I firmly believe in bone/charcoal and some secret sauces.....unless originally cased using the cyanide process, like Sterlingworths after 1912 or so, Savage, Sears, later Ithaca's etc....the cyanide process uses a lower temperature and the carbon layer will seldom exceed 1 mm and is not as uniform as the bone/charcoal hardness.........IMO........

I don't publish my times, temps and propriatary information that took me over 20 years to tweak, sorry, but I hope this helps in what you are looking for.....

Best,