case hardening ?
read on another site that a fellow had an Encore that was from the Custom Shop that was case hardened. No pictures or other info but now I have the hots for one. Any names or info on were I could get my Encore or Contender done?
got an email back from Turnbull, won't case harden an Encore as TC already CH to a deeper/harder degree and if DT did it again it would be softer than TC's. May have to wait until TC reopens the Custom Shop.
got an email back from Turnbull, won't case harden an Encore as TC already CH to a deeper/harder degree and if DT did it again it would be softer than TC's. May have to wait until TC reopens the Custom Shop.
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Run-N-iron. Do great work. 0 -
Had an Encore from the custom shop. I understand they are done by
Doug Turnbull. Beautiful colors.0 -
Be aware not all steels are created equil. To color case harden any piece of steel & predict the results you first have to have some idea of the carbon content of the piece you wish to color. Mild steel (read low carbon) will work best. The higher the carbon content, the more likely you will end up with brittle rasther than case hardened (surface hard & low carbon tough core).
I'm just say'en 'cuz it's purdy, don't make it right for every application. You gots to do your homework.0 -
you are correct Forge, I want case colored ! THANKS
Ping - heard of Turnbull, haven't seen his work.
Duck - were is Run-N-Iron ?0 -
Blanchard Metal Procesing would be my first call.
http://www.bmproc.com/
SZFranski's would be my second. 608-221-3008
I hope this number is still current.0 -
47studebaker,
Here is an excerpt from a definitive article found in Double Gun Journal about case and color case hardening:
The Double Gun Journal
The Color Case-hardening of Firearms-Part I
by - Oscar L. Gaddy
Case-hardening involves a process called carburizing which produces a thin layer of very high carbon steel on the surface of an iron or mild (low carbon) steel substrate. If the surface carburized steel is then heated to a high temperature (above the so-called critical temperature of approximately 720 degrees Centigrade) and then quenched rapidly by immersion in water, the high carbon steel layer (case) undergoes a phase transformation and becomes very hard and is extremely wear and corrosion resistant. The steel beneath the carburized skin or case is unhardened and remains as tough and resilient as it was before the carburizing and quenching. Both the carburizing and the quenching and hardening constitute the case-hardening process.
Carburizing can take place by a variety of methods. One method, which is also one of the oldest, is a process called pack hardening where the mild (low carbon) steel substrate is packed in a closed, but not air tight, container with the carburizing agents such as a bone and wood charcoal mixture. At elevated temperatures, the carburizing agents chemically produce an atmosphere in the container that is predominately carbon monoxide plus a small amount of carbon dioxide. At these high temperatures, carbon monoxide reacts chemically with the iron near the surface of the mild steel substrate to form the chemical compound iron carbide, which diffuses a short distance into the substrate steel. Pure carbon or wood charcoal alone is not an effective carburizing agent as it produces very little carbon monoxide in a closed container at elevated temperatures. Another substance, usually called the energizer, is added to the wood charcoal to facilitate the production of carbon monoxide in the closed carburizing container. This is the main function of bone charcoal in the carburizing mixture.
The higher the temperature and the longer the substrate is left in the container at this high temperature, the greater the depth of the carburized layer. Strangely enough, the equilibrium chemical kinetics of the carburizing process produces higher surface carbon concentration at lower carburizing temperatures albeit with a correspondingly thinner layer of carburized steel. This phenomenon has great significance in the case-hardening of firearms parts (with colors) as only very thin carburized skins are usually necessary for firearms in most cases, particularly if a good quality low-carbon mild steel forging is used for the parts. Other organic materials can also be used for carburizing and mixtures of organic materials with certain metallic salts as energizers are used in commercial pack carburizing materials today. In most commercial pack-hardening operations, the carburizing and quenching are two separate steps in order to conserve the reusable carburizing material. The carburizing and quenching can also take place in the same step by merely dumping the hot substrate and carburizing material together into the quench bath after carburizing has taken place. This is the usual procedure for small parts and is, probably, how color case-hardening was discovered. When small parts that have been carburized with bone and wood charcoal are quenched in water in this manner, they often, but not always, show interesting decorative colors and color patterns. These colors range from straw color to brown, dark blue, light blue, white and shades of red, and are closely related to, but not identical to, temper colors that one obtains by heating polished steel in air to temperatures of 400 to 600 degrees F. The composition of the thin-colored layers will be discussed below.
http://www.doublegunshop.com/doublegunjournal_v7i4_9.htm
Best.0 -
The process is as nononsence says.
The reason for case hardening is economic; to easily obtain a good final finish with free machining low carbon steel as case hardening predates today's high alloy cutting tools and also to be able to get a very hard surface on the order of Rc60.
Warpage that follows a through hardening of steels .035%C or greater is avoided. Equally important is finish machining of the hardened steel that older tooling couldn't handle is eliminated.
Complicated castings,accurate small parts and forgings like SAA and shotgun frames would have been impossible to machine and finish machine after hardening using higher carbon steel and older tooling.
The decorative coloration of cyaniding and bone pack hardening is a bonus not the object.
Colt used to sell SAAs on order with soft, uncasehardened frames to be engraved. They also sold some with blued soft frames.
Certain modern steels can be case hardened by nitriding resulting in a hard surface with a very strong core but you wont get the colors.
It can be simulated but not duplicated on alloy or hardenable steels.
To use these processes in an attempt to duplicate color case hardening
would be dangerous on steels containing .035% C or greater as through hardening & embrittlement would occur in at least the thin sections.
Note the color case hardened interior parts of S&Ws that don't seem to wear.0
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