Gallery, Projects and General > Mod-Ups!
Case Hardening Experiments Mod-Up
awemawson:
I believe that practically any source of carbon will work, and the various additives are to speed up the absorption process. I've heard of all sorts of weird concoctions being used, but with the exception of the Kasenit look-a-likes, the thing in common is heating for a long time in a sealed atmosphere to minimise oxidation.
vtsteam:
These are some of the theories commonly presented. Anybody want to actually try out a paricular method? and check results?
The sugar version I'll try today. Doesn't mean someone else shouldn't do the same material, since it is almost guaranteed that different people will use different procedures, and I'm guessing those can produce different results....
Lew_Merrick_PE:
The method we used in the tool & die shop where I apprenticed was to pack the parts in a (terra-cotta) ceramic "bowl" (more like a fully-bottomed cylinder) using bone mean and molasses as the pack. This was covered with a slightly larger "bowl" (ditto) that was set into a coke forge on "dull-red" heat and left for 10-12 hours of "soak." We then let the container cool before disassembling it and removing the parts. We then fired up the parts to a "medium-red" and quenched them (usually Puget Sound salt-water).
We got consistent .080/.060 inch casing this way. I last did this in the late-1980's.
Manxmodder:
--- Quote from: awemawson on May 09, 2015, 12:20:44 PM ---I believe that practically any source of carbon will work, and the various additives are to speed up the absorption process. I've heard of all sorts of weird concoctions being used, but with the exception of the Kasenit look-a-likes, the thing in common is heating for a long time in a sealed atmosphere to minimise oxidation.
--- End quote ---
Agree with you, Andrew, any source of carbon will permeate into the steel. Once it is in there the steel can be treated in the normal way the carbon steel is hardened.
When I was a little lad the local blacksmith/farrier used to gather up all the horse hoof trimmings whenever he shod a horse.
These and old leather pieces along with the item to be hardened were packed into metal boxes and sealed with fire clay. He then put the boxes in the forge and left them at bright red allowing the steel pieces to absorb a case of carbon. The longer the metal is in contact with the carbon at red heat the greater the depth of case carburising becomes.........OZ.
Edit to add: A mate who does a lot of gun smithing tells me that carburising parts using small leather pieces gives the component a mottled finish often seen on older gun parts.
vtsteam:
Okay back to experiments, which is what this Mod-Up is actually about....
I removed the scale from 5 pieces of 1/2" x 3/32" from a ten foot length of ordinary hot rolled steel. I added a beveled end as a pseudo cuting edge and labelled them C for Control, S for Sugar, A for Air, and 1 and 2 for other trials.
C would not be heated at all.
S would be an attempt to case harden with sugar
A would be another control which was heat treated the same as S, but would not receive sugar.
Here's the setup. A MAPP torch, cup of granulated cane sugar, and a container of water to plunge the pieces into.
Please notice I am going to use controls and the same stock and method throughout. That is important to avoid jumping to conclusions from a trial of any material by itself. I personally think that the failure to do that is responsible for many errors of opinion on the Internet.
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