Dave Leppo

"cherry red" case hardening compound

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They make several "instant case hardening compounds" casite or something like that is one of them. Be very careful when using them, get the MSDS and read it thoroughly before use. Some of these compounds contain very toxic materials. I have heard that some contain cyanide but I have not documented that myself.

It is a very slick video but instead of the bluegrass music it would have been nice if they would have mentioned what steel they started with. It wouldn't be hard to get a Rockwell 55 our of a piece of W-1 but it would be much more difficult to get the same results with a piece of mild steel.

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The speed at which carbon diffuses into steel depends upon the temperature and the difference between the %carbon in the steel and the %carbon in the compound or atmosphere. At 1750F and a carbon potential of .6% in the carburizing compound, a .20% steel will absorb carbon at the rate of about .007 inches per hour. Don't expect much from an "instant" hardening powder.

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You can case harden with charcoal by enclosing the charcoal and the item to be hardened in an iron box, or a wad of clay , anything that won't burn, and putting the whole works in the fire for several hours. Somewhere I have a table with how long to leave them for a certain depth of case.
Finnr

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So I get the steel, clean it up, put it in a lump of clay surrounded by powdered charcoal. Then I put it in a fire and, effectively, forget about it for a few hours? Is it as simple as that? Then eventually take it out, crack ioff the what is now pottery and clean up the steel again. I will try that next time I am going to have a hot and long lasting fire- possibly next time we roast a whole animal.

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White sugar has lot of carbon in it. Ive been told that pow tunnelers in ww2 used it to case harden their digging tools. These were usually a tin can that had been slash cut and a handle added. As a youth I had limited results trying this,I dont bother now as I prefer to use a more appropriate material such as tool steels or other more high carbon steels.......Kerry

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Pretty crude Philip but I have done it. Wrapping the item in leather and encasing it also has worked for me. Jack Andrews has some formulas in New Edge of the anvil.0ne being:
Hardwood Charcoal 55%
Barium Carbonate 20%
Sodium Carbonate 15 %
Calcium Carbonate, 10 %

I haven't tried all that, just carbon bearing stuff!

Be sure the clay is fully dried. Steam bombs are nasty.
Bring to critical temp.
An example given is Mild steel held at 1600 for seven hours will have about 1 /32 of an inch of penetration.

I tried it on a lark , I figured if a backwoods blacksmith could case harden the frizzen of a flint lock rifle I should be able to as well.

Give it a shot, the most you can lose is your test piece. And you still get a nice roast critter!
Finnr

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Not exactly carburizing, but will work to surface harden mild steel, non toxic, and easily available, this is a very old method to use.


Take a spoonful of wholemeal flour, add two spoonfuls of salt, add a little water and make into a smooth paste.

Heat the end of the item to be hardened until the paste will stick to it, when you have the item coated where you want it, heat the area to a bright red heat and plunge the item into cold clean soft water. The coated area will be appreciably harder.

An ideal way to make a quickie tool more hardwearing.

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John B That sounds more like a type of super quench than case hardening. The use of salt in water will make it quench faster/harder so would attaching the salt directly to the blade with a flower glue make it even faster?

Will have to give it a try next time I need to get some a36 a little harder.

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That may well be, all I know is that it worked for the oldtimers (me included)

I was lead to understand that carburized material is not hard untll you actually complete the process by whatever means, usually a quench.

I have and do use the 'Kasenit' hardening compound which contains highly toxic chemicals, I have had this for a number of years now, it still works although it has eaten its way through the metal can it came in, it now resides in a sealed plastic container.

The practical effect when using both these methods is to all intents and purposes the same, although a metallurgical analysis may reveal differences. However the flour and salt solution is not as offensive on the old nostrils, and a darn site cheaper and easier to source.

It is particularly useful for a wearing surface.

Edited by John B
Added use

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It is particularly useful for a wearing surface.


This is the part I was wondering about most, case hardening is only a few thousands thick but a quench will be much deeper if not throughout the object. Will be an interesting test, as soon as I get time. I wonder how well combining the 2 would do?

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Interesting theory but if each works, why waste energy (especially mine) in duplicating processes?

I have used both methods with equal success for spring swages, forming dies, vice jaws, flypress tooling, sliding parts etc.

Case hardening is NOT suitable if tools are going to be ground or sharpened, there is a very limited depth of hardness which will resist wear.

Use the correct type of steel for the job in hand.

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You must quench the case after you heat it up with whatever chemicals you use. Just putting the powder on is only half the process. The powder add a bit of carbon to the steel right at the surface and when you quench it, you get a very thin skin of martensite. The steel under the case will be softer but may still be hard enough to support the hard shell. A36 would probably work.

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Finnr said........."I tried it on a lark , I figured if a backwoods blacksmith......"
didnt the feathers get in the way?? Didnt it smell funny???
did you eat the bird later????

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They make several "instant case hardening compounds" casite or something like that is one of them. Be very careful when using them, get the MSDS and read it thoroughly before use. Some of these compounds contain very toxic materials. I have heard that some contain cyanide but I have not documented that myself.


Plasma nitriding - Wikipedia, the free encyclopedia

Gas and Liquid Bath Nitriding

Gas Nitriding or diffusion nitriding or ammonia (diffusion) nitriding has been around for nearly a century. It is a simple and inexpensive method for surface hardening of 'nitriding alloys' i.e. alloy steels with nitride forming elements and other metals e.g. aluminium, chromium, molybdenum and titanium to name but a few.

Liquid bath nitriding or salt bath nitriding on the other hand is not a classical nitriding technique but rather a carbo-nitriding technique, since it employs rather toxic salts of sodium cyanide. These salts break up at high processing temperatures, as high as 510 degrees Celsius up to 610 degrees Celsius depending upon various factors. This technique produces only a thin 'chemical compound zone' which is hardly 4 to 10 micrometres thick, with no underlying hardened sub-surface. In developed nations, the use of such toxic salts is banned, whilst the process thrives in the Third World without any restrictions, or circumvention of slack laws and regulations.

ect

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On the surface it seems to me as though this case hardening might offer neat potential for very thin/narrow blades such as used by detail carvers. For some that I know the blades resemble tiny needles more than they do toothpicks. I wonder whether the process could be tuned to allow these blades to survive the process though.

I admit that I have been making blades that tend in that direction lately and they are AMAZINGLY EFFECTIVE! Of course I have been using pretty good junkyard steel to begin with. My blades still look like large roughing blades compared to the most delicate ones I have seen but they are much finer than any being sold through regular suppliers. It is kind of shocking to use such small knives to remove so much wood so fast and with so little effort. The tiny cross-section of the blades seems to reduce the force required to make the cuts to near insignificance... even in very hard woods.

It just seems that for thin small items the depth of case hardening would be relatively insignificant as they could be hardened clear through and they are not suitable for any heavy grinding anyway. Take any significant material off of one of these blades and you'd have nothing left.

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Tried this a few years ago and wrote it up for the UMBA newsletter. I took a 12" chunk of 1018 cr and heated one end and forged to about 3/16" flat and quenched it. Then I forged the other end to 3/16" and fluxed with borax and coated it with cast iron turnings from a brake drum lathe. Heat it just below a welding heat and quench it. One end clamped in a vise bent to a 90 and the end with the castiron turnings fractured when I tried to bend it. Don't know how high the carbon was but it was hard. It's not case hardening but it did get hard.

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instructions from Rose Mill inc for the use of their "Cherry Red Compound"

�� Thoroughly heat the part to cherry red in color. Be sure the part (or section of the part to be hardened) is completely heated for best results.
�� Coat part in Cherry Red compound. Cover all surfaces to be hardened. Compound will blister and harden. Reheat part to cherry red color.
�� Quench in water, oil, or let cool and brush off excess compound. Cherry Red is water soluble and excess can be removed with water and a little brushing. distributor inquiries welcomed Made In USA Rose Mill Co. 122 Park Avenue East Hartford, CT 06108 USA
[860]289-4098 ph [860]289-2098 fx
Rose Mill Co. - chemicals lubricants processing
[email protected]
ONLINE PRICING Other ThermaRose Products:

PBC scalle prreventtiing compound
-prevents scale & pitting from heating
-protects surface finish
-helps eliminate buffing, cleaning, and re-machining

WILCARBO pack hardeniing compound
-provides deep case penetration
-superior hardness results
-effective on most stainless steels
$75.00 5#
$125.00 10#
$240.00 25#

R heat treating compounds ThermaRose Rev. 1/12/05 Supercedes

Edited by mod07
formatting

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what is the advantage of case hardeing? i assume wear resistance but wouldnt ar series plate be better in the long run? just my thoughts but i may be wrong on this.

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F-N; if I bring you a gear can you apply AR plate to it and get it back in spec? Cheaply?

Many things may not need a more expensive alloy but could profit from a little surface hardness. Some things are hard to make in a tougher alloy but could profit from a little surface hardness.

In the commercial word *cost* plays a big part in how things get made.

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The primary advantage of case hardening is that it permits a hard surface to resist wear or deformation while maintaining the strength and flexibility of the parent material. It is also a great saving on material cost. Further more it is available 24/7 which is not true of sophisticted alloys.

Quick hardening compounds like "Cherry Red" are used primarly for wear or temporary and or disposable dies. It also allows a better finish on the surface than is available with alloys like A36. If you were making a leaf veining die and put a good finish on it you might use a quick hardeing on it to keep the finish until you had made the 50 or so leaves needed for you project.

WILCARBO pack hardeniing compound
-provides deep case penetration
-superior hardness results
-effective on most stainless steels
Is used most often for hardening gears, shafting, and production dies.
Pack case hardening takes a while but produces superior results.
Thin edges often get over hardened and become brittle and so you need to think through the geometry of the item you are working with

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Mr. powers i do not have the facilities or skills to plate a gear or sell it no less! i am just posting my thoughts and wanted to know the advatages of case hardening. true it is cheap but the idea of leaving flexibilty intact did no occur to me and the cost of a disposable tool did not either. but i guess if it works it works. but as the case is a few thousandths of an in thick would'nt it abrade away over time in the long term? but i am not saying case hardeing is bad i just would like to know what the advantages are and why people like it. as thomaspowers said (well at least the meaning) cheap beats expensive for short term tools.

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