CCH and 'secret ingredients'

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Markbo

Bearcat
Joined
Aug 15, 2006
Messages
30
Location
Texas
This may be a silly question, but what kind of 'secret ingredients' may be part of the professional CCH process? Is it chemicals, or animal or mineral products? I know nobody will tell us what they are exactly but I am always curious what type of products they are.
 

flatgate

Hawkeye
Joined
Jun 18, 2001
Messages
6,784
Location
Star Valley, WY
Black Magic performed by Witch Doctors!

Here's a quick description I just found...

"Case Hardening" is a form of "carburizing" - a process that applies a thin carbon skin to the surface of low-carbon steel objects in order to make the surface more wear resistant.
This carbon skin is achieved by
* applying carbon bearing materials (usually in the form of powdered charcoal, bone, leather, or a commercial preparation such as "Casenite" or other similar materials) to the surface of the steel object * wrapping the whole thing to keep the powder in direct contact with the steel and to keep air (oxygen) away from the surface
* Heating the entire mass to "red heat" which causes the carbon to be absorbed at the surface of the steel forming a thin skin of "high carbon" steel. * "Quenching" the part by plunging the red-hot mass into cold water to harden the "carburized skin".
This results is a slightly mottled gray colored finish which is "glass hard" and brittle for a few thousandths of an inch in thickness, but leaves the body of the steel object tough, strong, and ductile.

"Color Case Hardening" adds steps to the above process, such as bubbling the water, or packing the part in loose carbon material in an airtight box prior to heating, then dumping the contents of red hot box into the cooling water. This causes almost random contact of air, gases from the heated carbon material, the steel object, and water producing a pleasing mottled blue/purple/ gray, brown/ red colored surface in addition to the hard, wear resistance surface.


Ruger's steels do NOT take to this process very well. It has been a problem that has recently been solved by Turnbull, I do believe.

flatgate
 

WOB

Bearcat
Joined
Feb 18, 2007
Messages
98
Location
Central Texas
There's a lot of myth, magic, and snake oil spread around about the process. The ingredients include a source of carbon which is usually bone, leather, or hardwood charcoal and an activator added to the mix to speed up the movement of carbon into the steel surface. I have read that a common activator is a mixture of barium carbonate and sodium carbonate. Both chemicals are readily available to the public. There may be other components added by particular smiths, but the above is all that's really needed.

Case coloring a through hardening alloy like 4140 is for decorative purposes only as it's proper heat treatment precludes the traditional process.
In that case, ( no pun intended) the charcoal is simply used to prevent atmospheric oxygen from reacting with the surface until the container is broken open at the quench.

WOB
 
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