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Case Hardening - can't even harden a washer !

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C W29/06/2011 00:06:48
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Don't suppose you remember where it came from Andy P ?
AndyP29/06/2011 12:04:55
189 forum posts
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CW
Andy
C W29/06/2011 16:02:05
10 forum posts
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Phoned Blackgates and a very nice lady went and checked the case hardening compound, and she confirmed it is the type that sticks, duly ordered ! 11GBP plus VAT plus P+P for 400g. Thanks AndyP.
 
Meanwhile after buying some of the worse BBQ briquettes I have even seen from Pound Stretchers (you know the saying "There's no smoke without fire" will if it comes from Pound Stretchers there is a very strong chance there will be and lots of it), I am back on track. Got 8 bricks, a little steel mesh and an 80mm computer fan keeping my washer just toasty. Going to try for an hour and see.
 
Cam.

Edited By C W on 29/06/2011 16:10:03

C W29/06/2011 16:15:13
10 forum posts
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In progress
 


C W29/06/2011 18:26:17
10 forum posts
2 photos
Well after an hour and a half, it's harder, but not what I would call hard. You can still file it or scratch it with a scalpel but a stainless steel kitchen knife won't touch it. Am I expecting too much ? Hopefully the Blackgates compound will be a different tail.
 
EDIT. I take the above back, when filing it back to back with a standard washer it is a fair bit harder. Not untouchable by file as I have seen it described on the net, but much harder work to remove any material.

Cam.

Edited By C W on 29/06/2011 18:36:46

Clive Hartland29/06/2011 19:23:29
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2929 forum posts
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I would then suggest that the washer is made from some type of inferior steel sheet, it is after all only a washer!
 
Please try to harden a piece of machined steel that has been made to do something like a bush or a flange. It need not be a big thing so make it about 1" dia with a bushing and a flange.
Drill a hole through it and try again.
 
Clive, PS you might be able to use it later as a guide when drilling something.
C W30/06/2011 15:18:37
10 forum posts
2 photos
Went to a local forge up the road today, got some mild steel bar, but the guy had no clue as to what grade of steel, so no better off really, mind it was free so not all bad.
 
So where would you guys send me to get some steel in small quantities of a known grade such as:
 
080A15
024M10
210M15
214M15
EN32B
EN32M
EN202

Apparently these are all suitable for case hardening.
 
Cam.

Edited By C W on 30/06/2011 15:41:54

Michael Cox 130/06/2011 19:11:01
555 forum posts
27 photos
Hi CW,
I always buy metal from m-machine (www.m-machine-metals.co.uk). Very helpful people and can sometimes get special grades on request.
Steel washer are probanly stamped from a cheap grade of steel like EN3. This should be case hardenable. Steel from the local forge is likely to be cheap EN3 also.
Mike
jomac01/07/2011 11:28:41
113 forum posts

Hi, saw an old recipe for case hardening a few years ago, that contained, charcoal, bone, horn, ground up leather, ( use the wifes grater ) that was mixed with molasses to a thick paste, the sugar in it turns to carbon,?????, have not needed to case harden yet, but might try this method as I think the molasses would stick to the job better.

John H.

Ian S C01/07/2011 12:10:01
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7468 forum posts
230 photos
Went into christchurch today (I don't go often, its a bit of a desert these days, buildings down etc), was in one of our leading engineering retailers, and found a 1 lb tin of kasenit on the shelf for $NZ 74. 45, so it's available in New Zealand at the moment. I did'nt buy any, as I have 3/4 of a tin I bought at the same place 25 years ago. Ian S C
Gordon W01/07/2011 13:41:17
2011 forum posts
I remember reading that would be escapees in German prison camp case hardened some home made tools by packing in sugar and putting in the stove. Sugar has lot of carbon of course.
Steve Withnell01/07/2011 13:42:26
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858 forum posts
215 photos
Posted by C W on 28/06/2011 21:02:39:
Just tried washer No2 in a little container with enough powder to coat it, and blow torched it for 5 minutes or so. Result was no different unfortunately Suspect I didn't get it/keep it hot enough. Off tomorrow to buy some BBQ Charcoal I think, will report back.

Doesn't the blow torch simply blow the Eternite away? I've used this stuff and have had hit and miss results to be honest. I've tended to pack the part into a tin and heat it to "carrot" for a while, then left it to cool. Then re-heated the part directly to "carrot" and immediately quenched. Works but I do not get good consistent results.

C W04/07/2011 22:26:35
10 forum posts
2 photos
Well my hardening compound from Blackgates arrived. Within 5 minutes I had created a washer harder than the eBay obtained Ethernite produced in 1 1/2 hours. Much much better stuff.
 
And I can confirm it's the type that sticks and it contains Potassium Ferrocyanide.
 
Thanks for all the help guys !

Edited By C W on 04/07/2011 22:28:02

Cyril Bonnett05/07/2011 20:49:51
250 forum posts
1 photos
May be useful to know that many gunsmith companies sell these products

http://www.blackleyandson.com/acatalog/Compounds_and_Solutions_for_Metals.html
Steve Withnell05/07/2011 22:20:21
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858 forum posts
215 photos
From Blackleyandson website:
 
"FILL CONTAINER WITH TWO PINTS OF TEPID WATER. ADD ONE TABLE SPOON OF SALT PETRE AND MIX. HEAT PART TO RED AND DIP INTO COMPOUND. REHEAT PART AND ALLOW THE COMPOUND TO MELT AND FLOW OVER SURFACE OF PART, AND PLUNGE INTO WATER. WASH OFF REMAINING COMPOUND".
 
What's the purpose of the Saltpetre in the quench?
 
Regards
 
Steve
 
 
 
John Stevenson05/07/2011 22:50:44
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5068 forum posts
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Posted by Steve Withnell on 05/07/2011 22:20:21:

 
What's the purpose of the Saltpetre in the quench?
 
Regards
 
Steve
 
 
 
It replaces the virgins blood that was used years ago seeing as the last know sighting of a virgin in the Midlands was on the Cadbury works outing in1937.
 
John S.
Chris Trice05/07/2011 23:13:54
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1376 forum posts
10 photos
I don't have an exact answer Steve but I know traditionally there's a history of using salty brine to quench with. It apparently gives better results. Might have to dig out the ol' hardening and tempering metals book.
Chris Trice18/07/2011 21:58:18
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1376 forum posts
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Suitably inspired by this thread, I had a go for the first time using the powder from Blackgates. Easier than I was anticipating. I was heating a freshly turned piece of mild steel about 14mm diameter and about 30mm long. Heated to bright orange/carrot, dipped it in the powder and made sure it had a good coating then returned it to the firebricks and continued to heat it and keep it bright orange for aprox 5 minutes before quenching it in brine. Cleaned all the gunk off with a fine steel brush and tested it with a file. Clearly much harder to the point where I didn't want to push it too far for fear of taking the edge of the file teeth. The salt in the brine BTW apparently delays or helps to stop the formation of steam bubbles on the surface of the metal as it's quenched.
Chris Trice18/07/2011 22:04:09
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1376 forum posts
10 photos
...And coating the hot item in powder reminded me of silver solder flux but black and more granular instead of white and powdery. It melts and bubbles in a similar way before solidifying into a crust around the workpiece.
mgj19/07/2011 10:59:42
1017 forum posts
14 photos
I don't normally come here but......
 
We have got ourselves in a mighty tis was, and it might be worth reading Hardening and Heat Treatment more carefully.
 
Basically there are two separate processes.
 
There is the the slow carburisation process, which involves old bits of bone, leather etc, and more "modernly" various carburising powders. The process involves (normally) sealing in some airtight box, (not always depends on the powder)raising all to the appropriate temperature and then iron being a solid solution, the carbon migrates through the material at a particular rate enriching the surface with carbon before being quenched. It is slow, but depth of case can be more or less as deep as you want, properties are very controllable and there is les risk of distortion. Much used in industry.
 
The other is the Kasenit type process, much more suited to our sort of setup and effective enough for what we want.
 
Nothing inferior about anything, nothing went wrong - just a case of the right powder for the wrong process or vice versa. Full details are in Tubal Cains book in the chapter about case hardening.
 
Brinne is a good idea if you are stopping a tempering/heat treatment process (at say light straw), or if distortion is likely to be a problem - mostly it isn't because the substrate is in our cases mostly non heat treatable mild steel. We don't really toughen or otherwise heat treat solid steels other than Silver steel.
 
It has little effect on case hardening because all one is doing is freezing the crystal structure in the martensitic condition. IOW you are stopping the carbon rich surface from transforming back into pearlite, which it will do if allowed to cool naturally. So as long as you cool it faster than it can transform, and that you will do with water, the system will work perfectly.
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