Case hardening mild steel

[Rik ShawParticipant @rikshaw]

[Rik ShawParticipant @rikshaw]

I bagged a 32×3 indexable parting blade with tips recently and I'm part way through making a holder for it out of MS. When it is finished I intend case hardening it but I have not case hardened anything since I was at school when dinosaurs roamed the earth.

The holder will be quite a lump and I have not really worked out exactly how to tackle it but I am considering using this stuff as a hardening compound.

**LINK**

Has any one used bone meal before and if so how did you get on?

Rik

[Capstan SpeakingParticipant @capstanspeaking95294]

Are you sure it's carbonaceous? You might be better off with powdered charcoal.

There are modern equivalents of Kasenit too but they're expensive.

[Clive HartlandParticipant @clivehartland94829]

Rik, whatever you do you will have soak heat it in a semi sealed container, the bone meal is not enough on itself and I would as I have often said use leather and mix it in small pieces. Add some powdered charcoal to make it incandesce. For mild steel I would suggest at least a half hour at heat and then dunk the contents into cold water, then test for hardness and if no good do it again. This should give a very hard skin but not of very great depth.

Semi sealed container can be a welded box with just a lid laid on top. Easier to tip out.

Clive

[jason udallParticipant @jasonudall57142]

Case hardening.
Not a process I have recent experience with.

But we used kasamite.. or however spelt.

Mild steel..heat to orange..plunge in tub of powder..reheat and retreat

Four such followed by quench from orange /yellow..just starting to sparkle. .
Proved hard enough for can openers and even on one test glass “cutter”
.
Now since this is a surface treatment I guess no benifit derived from soak.
..does the soak help?…
I guess the idea is to allow a deeper impregnation of the carbon..still don’t know.

[Clive HartlandParticipant @clivehartland94829]

Heat soaking is a recognised way of increasing the depth of case. I am now going to go back to my text books to refresh my knowledge. I have made small gun parts and case hardened quite successfully. Also made parts from spring steel, extractors that take a bit of a bashing. and hardened and tempered them. A gun without an extractor is useless.

Clive

[Capstan SpeakingParticipant @capstanspeaking95294]

Steel won't absorb extra carbon unless it is above roughly 700 degrees. The longer it is kept there, the more it will absorb.

One industrial process is to bake it in a carbon monoxide filled oven.

[Axel BentellParticipant @axelbentell]

If you want to colour case harden them, which is the same thing really except you get them to look pretty as well, I suggest The Machinist's Bedside Reader No2 and No3. Guy Lautard of Canada has in depth explanations how how it is done.

Other than that I know that the old gunsmith trick was (is) to just wrap the part in leather and bake in clay, but I have never done this, since I always used Kasenite that can be ordered from Brownell's in the USA. Or perhaps Triebel in Germany who also sells sundries and tools for gunsmiths.

[LambtonParticipant @lambton]

Why do you want to case harden it?.

DIY case hardening will only harden a very thin layer at the surface of the item if at all.. It will not make the mild steel any harder, tougher or provide any other enhancement of physical properties.

If you really want it case hardened take it to a local heat treatment company that will have all the materials and facilities to do a guaranteed job.

[Ian S CParticipant @iansc]

For tool holders I use old car half shaft, it's hard work, but more durable than mild steel.

Ian S C

[BubbleParticipant @bubble]

Hello All

Has anyone on the forum tried case hardening using Granular Activated Charcoal (GAC) pellets?

I have a borehole water system here in Wales which uses filters containing this. I have not had the opportunity yet to try using the material from a "spent" filter. (I also have a big tin of Kasenite so there has not been the necessity to experiment, as this will last me another 50 years and I'm already 70!)

Used filters would probably be available for free from domestic water system engineers (there's lots of borehole systems in Wales) and as far as I know they are not recycled in any organised sense.

Alternatively, GAC can be bought on the web at about £10 per kilo.

Jim

[Roderick JenkinsParticipant @roderickjenkins93242]

Posted by Lambton on 23/06/2015 09:44:11:

Why do you want to case harden it?.

DIY case hardening will only harden a very thin layer at the surface of the item if at all.. It will not make the mild steel any harder, tougher or provide any other enhancement of physical properties.

Case hardening completely changes the finished properties of the hardened layer. The usual reason to case harden is to increase the wear properties of components like cams and slide bars.

I have to agree though that in this case I don't think case hardening will improve the tip holder. If it's anything like my Qcut holder then some spring is needed to retain the tool and case hardening won't help you. I would use gauge plate which can be hardened and tempered as required.

Cheers,

Rod

[Rik ShawParticipant @rikshaw]

Rod – I think you might have the wrong end of the stick. I am not contemplating case hardening the tip holder / blade as that part has already been dealt with by ISCAR:

The part that I am making is the holder that will grip the above blade / tip holder. Something similar to this:

Why do I want to case harden it? Fairly obvious I would have thought.

Rik

[Roderick JenkinsParticipant @roderickjenkins93242]

I certainly have picked up the mucky end

I'm not totally convinced that case hardening will improve the part – I wouldn't have thought that wear will be a major issue. However I have bought some of this from EKP which may give a better result than pure bonemeal or carbon.

Cheers,

Rod

[MuzzerParticipant @muzzer]

I wouldn't (didn't) bother. The number of times it gets adjusted is minimal. I forget what material I used but it wasn't EN1Pb or whatever. I wonder if the Iscar / Korloy / Sandvik holders are hardened in any way?

Murray

[Neil WyattModerator @neilwyatt]

Nice design Rik

I might copy that

Neil

[Rik ShawParticipant @rikshaw]

Neil – Thanks but I take no credit. The block illustrated is my WARCO supplied holder. Sadly it does not have the capacity for the 32mm wide Iscar blade hence my reason for making one. When finished it will have a 14mm square x 70mm long bar to the rear which will be gripped in my rear mounted tool post. I'll post results when completed.

Clive I've noted your advice re: using leather scraps for case hardening and have just found a large carrier bag full of leather scraps on the front door step. Our friend over the road works in a leather factory and these are their chuckouts  but my treasure.

Rik (contemplating some nasty niffs quite soon).

Edited By Rik Shaw on 24/06/2015 13:35:59

[Clive HartlandParticipant @clivehartland94829]

The case hardening technique is as stated in a closed environment, like a tube with one welded end and a plate lid, The item placed in a mix of scrap leather and bone and some charcoal Heat all to about 1300 temp. and discharge rapidly into cold water. It will have the hardest skin but not too deep.

[Neil WyattModerator @neilwyatt]

> Has anyone on the forum tried case hardening using Granular Activated Charcoal (GAC) pellets?

I have looked at Brita/Tesco water cartridges and thought the same thing.

Neil

[Frances IoMParticipant @francesiom58905]

I took one of these generic filters apart(can’t recall brand name) – seems more sand than charcoal in the one I chose though might explain why it clogs up fairly quickly – hard taps with a spoon gets flow working again.

[Michael Cox 1Participant @michaelcox1]

The chemistry of case hardening is quite simple. You seal the component in a container with carbon donor material such as charcoal and heat it to circa 800 degrees or so. The source of carbon is not so important it can be leather, bones, charcoal etc. It is useful to add barium carbonate or sodium carbonate as an activator (circa 10%). The longer you heat it the deeper the case. Like most diffusion processes the depth of the case will depend on the square root of the time. Thus it will take 4 time as long to double the case depth.

Kasenite and similar materials are slightly different in that they contain both carbon and nitrogen both of which are hardening agents for steel.

Mike

[Clive HartlandParticipant @clivehartland94829]

Part of the fill of filters is resin pellets that absorb the chalk and the charcoal absorbs the Chlorine. Im just thinking that if you use filter materiel you will end up with a resin coated component? aquarium filters are small pellets of carbon, not charcoal. It is also quite brittle. I still feel that you should use natural medium to get the carbon.Today i watched a TV programme that shows guns being made and they case hardened a body of a revolver and obtained a result where the surface was flame hardened, beautiful colours on the metal. This being done in a closed cylinder with leather cuttings and charcoal. very high temperature was reached.

Clive

[JohnFParticipant @johnf59703]

Hi Rik,

There are lots of posts relating to this, have a look at the link below or just search the forum for case hardening. To do the tool holder you will need a muffle furnace and a suitable container to be successful. As a general rule carbon penetration is in the order of 0.004" per hour of soaking at the required temperature.

Regards John

**LINK**

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