Newby: Advice needed - Packed Carburizing Questions

techymechy · Oct 22, 2020

I bought a Whitney 91 punch for cheap and found out that the punches and dies are an odd size and basically non existent. I went to Whitney and they want $40 for a punch and die set.

I would like to try my hand at making my own punches and dies. I would like to use 1018 cold rolled steel for the punch and die. I would then like to case harden the part by packed carburize the parts, heat treat, quench, anneal.

I watched many of the videos on you tube and one uses charcoal and an electric oven. I have an electric oven that has a inside volume of roughly a 6 inch cube that I'll be using for the carburizing, heat treatment, annealing, etc.

In the video, they used a steel box and refractory mortar to make an air tight seal when carburizing. Is it critical to have a very good seal? I need a steel box. I have been thinking of three options:

Option 1. Make a box out of 20ga. sheet metal with a slip on lid (reasonably tight fitting). I have some sheet metal and equipment
Option 2. Buy some 3/8" steel plate and bolt together a box. I don't have a welder.
Option 3. Buy a box....I can't find anything that might work except for the Hoffman electrical boxes.

I would prefer to stay away from the refractory mortar but I don't know how good of a seal I need for this process.

Option 1 may be too thin and it will become fully case hardened, and potentially brittle, from use. Also, I don't know how good of a seal I can make.
Option 2 won't be welded, but can be bolted together. It may be difficult to take apart. Also, I don't know how good of a seal I need.
Option 3 may suffer the same issues as option 1, and the Hoffman boxes come painted, etc. and I'm not sure I want to burn the paint off in my oven.

Please let me know your thoughts on how to make/buy a packed carburizing box for my oven and how gas tight I need to make the lid (do I need to use the mortar).

Dave

Illinoyance · Oct 22, 2020

Wouldn't it be easier to use O2 or A2 and eliminate the need to case harden?

techymechy · Oct 22, 2020

Shoot, I typed up an extensive reply to your comment, but it was lost...

I thought that O2 and A2 were through hardening materials. I read that A2 may be a better material for this application. I recently bought a programmable Jelenko dental burn-out oven for heat treatment of steels, etc. My oven does have the ability to program in the temperature profile required by A2.

I have machined about 6 set's of punches and dies out of hot rolled 1018. I read on this forum that 1018 could be used for punches and dies. I think that the material is a bit soft and my edges are rounding off with only a little use. Hence, I was looking for different things I could do to make a punch and die. That is how I came across carburizing case hardening. This seems like the right process for punches and dies.

This is just a hobby and I'm trying to learn new techniques. I thought it would be fun to learn the case hardening via packed carburizing process. The Whitney 91 punch shank is 0.5660" and the die is 0.872" OD. They are weird sizes and I'd have to machine the A2. I made a die shoe that will accept a 1.25"diameter die so this is a candidate for using a preground A2 rod. I thought it would be about the same effort, and a lot cheaper, to use 1018 and case harden it. I also think that a case hardened punch is probably better than a full hard punch (but I have no practical experience).

Makes sense?

Dave

crossthread · Oct 22, 2020

You might want to play with some Kasenite and see how that works for you. Cherry Red is another product but I haven't used that. I've been using Kasenite for many years and it does a good job.

techymechy · Oct 22, 2020

I've looked into Kasenite and Cherry Red. It is not really clear if Kasenite is still for sale. I've heard that both products only create a really thin case. I haven't seen any videos on how to make a thicker case or to use an oven. I don't have a torch so I can dip and heat into the Kasenite/Cherry Red.

This is one YouTube Video that I found very helpful:

Case Hardening - YouTube

Kasenite and Cherry Red are pretty expensive to be dumping a can into a container with my parts. I've seen where others have made a pouch out of sheet steel. My brother said I could add brown paper to the pouch to get rid of the oxygen in the pouch to keep the surface quality better.

The guy on YouTube said he could get a case of 0.063". That seems to be a better case thickness for my application (but like I said, I'm a novice).

Dave

john.k · Oct 24, 2020

For punches ,I think you would be much better off using a high carbon steel ,and hardening it by the "chisel" method.....which in one quench provides a hard edge and tough body.......Possibly the cheapest way to find a high carbon steel without buying a spec d bar ,is to use the one of the sets of cheap workshop punches ,which are generally HC,and easily hardenable.................If you want to case harden ,then the best mix is to use bone char and barium carbonate......this will give the deepest case in a shorter time.....Complete airtightness isnt necessary ,as some oxygen is needed to reduce the char carbon to carbon monoxide,which actually does the hardening......An old method that works is to drill 1/8" holes in the box,and insert wires inside......after a time ,pull a wire and quench it,break it to see the case depth developed.....If OK ,then quench the job.

techymechy · Oct 28, 2020

Hi John,

Thanks for the reply.

Does the punch and die both need to be hardened? I haven't tried to machine a cheap high carbon punch, but I'm afraid that my 9" logan isn't stiff enough - although I don't know if an annealed HC steel is very machinable.

If you look at the YouTube video, those guys use grill charcoal and sealed the chamber that they were using to impregnating the 1018 steel with carbon. After this, they reheated the part, quenched and then stress relived. I've been buying the scrap structural steel (A36?) which is not the easiest to machine. I'm going to experiment if I can get enough carbon in this to case harden. I'm thinking of buying two 4" black steel caps and a zero length coupler to make my chamber. I can drill some 1/8" holes in one cap and try the wire trick. I have a buddy who suggested that during the tempering (1400F) that I should coat the part with a mixture of Castle soap/carbon black to keep the surface from decarborizing during tempering/quench.

I have no idea where one get's bone char nor barium carbonate. I'm wondering if the bone stuff sold for gardening fertilizer is what I need. I still don't know how to get barium carbonate. This might be good to mix into the charcoal. Do you have any idea of the mixture (say mass ratio of carbon/bone char/barium carbonate)? I don't mind letting the oven run at 1700F for 8-10 hours and follow the other direction in the youtube video. This is just a hobby.

How do you check the case depth? I was thinking one would test with a file, grind and repeat until the file removed material.

Thanks for all of your help.

Dave

john.k · Oct 28, 2020

Bone char from the garden centre may be OK ,dont know......chemicals both mild and dangerous seem to be easily available from ebay......8/10 hours is way too much ....consider four better.......I would still forget casehardening,and go for the high carbon steel.......Hardening a chisel for a hard edge and tough body is so simple it used to be a school exercise.......Anyway,whats the machine....some massive effort with 2 ton flywheels ,or a tiddler?.....Carbon steel punches was plenty good enough for the railways big Bennie punch that did 3" holes in 1 " plate with one bang....Yeah ,bought that for $10 too.25ton.

techymechy · Oct 28, 2020

Hi John,

I am making punches for a Whitney 91 press. It is a 10 ton manual press, but I doubt I will ever come close to using it to it's full capacity. I bought two of them for $100 and they came with a couple of Whitney shoes. I made a shoe for 1 1/4" dies but the Whitney is a little smaller than 7/8". I was thinking of setting one punch up for 1/8"-9/16" and one punch for 5/8" - 1". I will probably rarely punch over 1" holes and rarely go thicker than 1/8" mild steel. Most of my work will be on 16 gage sheet metal (or thinner).

I need to look for the punch set's you mentioned earlier. Do you have any suggestions? I am hoping to make a full set of punches and dies from 1/8" to 1" by 32nd's of an inch. How would you make the dies? Do they need to be hard?

Dave

atex57 · Oct 28, 2020

Earlier you said you can buy the die sets for$40 ? BUY THEM!! Unless you are looking to do this for the fun of it you could pay your self $5 an hour and still lose.
Carburized punches made from C1018 will sink or crush if used hard, the underlying material is not strong enough to take a lot of pressure.

Ed.

techymechy · Oct 28, 2020

Hi Ed,

This is just a hobby for me and I'm trying to learn stuff. I totally agree with you that if I were a business and trying to make money, I'd purchase the punches (heck, I wouldn't have bought the presses I purchased). But, I'm still new in this hobby and am basically training myself by reading, watching videos, being a member of this board, turning big pieces of metal into little pieces of metal, etc. I'm really interested in how to take materials and modify their properties to meet one's needs. The punches are just an excuse to get practical experience in carburizing, heat treating, tempering, etc. Plus, there is a bit of satisfaction when one has gained the knowledge to make a usable tool which provides more capability in his shop.

I basically had a crap education in heat-it-and-beat-it metallurgy and machine shop practices. I did some meatball machining in grad school, but am getting close to retirement and am trying to build up my shop. I am not trying to buy my way into this, but am trying to develop my skills so I can make the most of what I have. I'm a firm believer that a skilled worker can do amazing things with what he has as long as he has the knowledge and drive to do so. Consequently, I'm not the guy who'll spend a lot of money to have a lathe that can keep 0.0001" over a foot, etc. I have a equipment that is OK (probably unacceptable to a lot of guys on this board), but the equipment is better than I am. I would like to improve my existing equipment and skills and potentially make some of the accessories/tooling to further my shop capabilities.

I found the 4" black iron caps and closed couplers on line and will be ordering them tomorrow to make my carburizing chamber. I purchased a Jelenko programmable dental burn out oven (about a 6" cube oven) that I will be using for my heat treatment work. This is actually fun. If my punches fail because they are made out of too low strength materials, then I'll make them again with a higher strength material. That is the fun of this hobby. You really don't make mistakes, you just have learning experiences.

Dave

dian · Oct 29, 2020

i got this:

BARIUM CARBONATE 99% 1 Pound lb Lab Ceramic Chemical BaCO3 | eBay

atex57 · Oct 29, 2020

techymechy said:
Hi Ed,

This is just a hobby for me and I'm trying to learn stuff. I totally agree with you that if I were a business and trying to make money, I'd purchase the punches (heck, I wouldn't have bought the presses I purchased). But, I'm still new in this hobby and am basically training myself by reading, watching videos, being a member of this board, turning big pieces of metal into little pieces of metal, etc. I'm really interested in how to take materials and modify their properties to meet one's needs. The punches are just an excuse to get practical experience in carburizing, heat treating, tempering, etc. Plus, there is a bit of satisfaction when one has gained the knowledge to make a usable tool which provides more capability in his shop.

I basically had a crap education in heat-it-and-beat-it metallurgy and machine shop practices. I did some meatball machining in grad school, but am getting close to retirement and am trying to build up my shop. I am not trying to buy my way into this, but am trying to develop my skills so I can make the most of what I have. I'm a firm believer that a skilled worker can do amazing things with what he has as long as he has the knowledge and drive to do so. Consequently, I'm not the guy who'll spend a lot of money to have a lathe that can keep 0.0001" over a foot, etc. I have a equipment that is OK (probably unacceptable to a lot of guys on this board), but the equipment is better than I am. I would like to improve my existing equipment and skills and potentially make some of the accessories/tooling to further my shop capabilities.

I found the 4" black iron caps and closed couplers on line and will be ordering them tomorrow to make my carburizing chamber. I purchased a Jelenko programmable dental burn out oven (about a 6" cube oven) that I will be using for my heat treatment work. This is actually fun. If my punches fail because they are made out of too low strength materials, then I'll make them again with a higher strength material. That is the fun of this hobby. You really don't make mistakes, you just have learning experiences.

Dave

If you are here to learn we will be glad to help. Making the punch and die sets will be good practice, C1018 may not be good but C1045 will have good strength after HT. O1 or A2 would be better. As far as carburizing, you don't need any thing fancy. I just pulled some Mauser 98 actions out of the furnace for a friend of mine. The pot is a stainless tube that has a plate welded to the bottom and simply has a SS plate setting on top while heating. If you have a front load furnace a heavy pot is good to hold heat while pulling it out and getting it all set up. You have to be careful on how you grip the pieces when you pull them out of the pot, if the utensil covers the wrong area you will not get an even quench. I use SS for the pots because I do not like all the scale that comes off carbon steel when heated. Any more questions?

Ed.

techymechy · Nov 16, 2020

I *finally* tried my first packed carburization this last weekend.

I bought this little programmable Jelanko dental burn out oven (roughly a 6" cube oven volume). It works well. I built my packed carburization chamber out of 3" stainless steel threaded pipe fitting; I bought two 3" 316 Stainless steel caps and a closed coupler. I broke up the wood charcoal and added the powder/small chunks to my chamber and then carburized a simple part in the stainless chamber for 8 hours/1750F. I'm following the Youtube example first, then going to experiment with the Barium Carbonate, etc.

My stainless steel chamber developed some scale and sluffed it off in the chamber. Is this normal?

The part is cooling off now, but I will be heating up to 1400F this afternoon for maybe an hour then quench. Hopefully I get a hard part. After the quench I'll stress relieve at 400F.

I notice that my stainless steel has scaled and looks to have rusted a little bit in the threads of the closed coupler. Is this to be expected?

Also, can I reuse the charcoal dust or should I just throw this away between each use?

Dave

techymechy · Nov 17, 2020

I finished my first scrap part and have a second batch in the oven.

My process was as follows:'
1. crush wood charcoal to powder form (with some chunks)
2. place 1" of powder in stainless steel pipe fitting box, place part on top, and fill to top of closed fitting. Note, I tapped the fittings to settle the particles. Gently tighten the top cap pipe fitting on the closed nipple.
3. place in cold oven and heat to 1750F at 50F/min. Let soak at 1750F for 8 hours
4. let parts cool in oven to about 200F, remove and place on bench. Cool to handling temperature
5. place parts in oven and heat to 1400F. Let soak for about 20 min. Look to see part color is uniform.
6. open furnace door and quickly place part in water, swishing part in water with figure 8 pattern
7. dry part and place in oven at 400F for 1 hour and shut off furnace and let air cool to handling temperature.

My first part is pretty hard. I really don't want to put out $150 for a set of hardness files. Does anyone have a method for grossly quantifying the hardness using common place materials?

I've read where one could use 90% wood charcoal and 10% Barium carbonate (as an accelerator). I think that this is by volume (but it could be mass). I read where one should replace roughly 20-25% of the packing carbon/barium carbonate per run. I'll have to buy a couple of pounds of this material and see how it works.

I'm running a second test where I have different diameter nails to get some sort of feeling for the case depth. It is hard to find information on case depth vs. time and temperature for wood charcoal materials. Hopefully, I'll be able to qualitatively determine case depth by evaluating the toughness of these nails.

awander · Nov 17, 2020

Looks like you are well on your way to becoming an expert on this hardening method.

BTW, it is a "close nipple", not a "closed coupler" or "closed nipple"

john.k · Nov 17, 2020

Wasting away of the carburization pot is just a cost of running at white heat....One of the reasons liquid cyanide was so popular back in the day.....As a further development ,you will find that making either the die or punch with an angled surface(called shear) will considerably reduce the force needed,and depending on which of the blank or hole you want flat.....I have no doubt there are plenty of old books on metal stamping in Google Books......................you dont need hardness files.....if a new fine file skids over the surface without drag,then you have a hardness of 60RC +.......If the file will just bite on an edge without stripping the file ,then 55-60RC.

D Nelson · Nov 18, 2020

You are pissing into the wind
A-2 d-2 or s-7 don’t waste your time with 1018 you can’t make chicken salad out of chicken shit
Don

Sent from my iPhone using Tapatalk Pro

dian · Nov 18, 2020

techymechy said:
I finished my first scrap part and have a second batch in the oven.

My process was as follows:'
1. crush wood charcoal to powder form (with some chunks)
2. place 1" of powder in stainless steel pipe fitting box, place part on top, and fill to top of closed fitting. Note, I tapped the fittings to settle the particles. Gently tighten the top cap pipe fitting on the closed nipple.
3. place in cold oven and heat to 1750F at 50F/min. Let soak at 1750F for 8 hours
4. let parts cool in oven to about 200F, remove and place on bench. Cool to handling temperature
5. place parts in oven and heat to 1400F. Let soak for about 20 min. Look to see part color is uniform.
6. open furnace door and quickly place part in water, swishing part in water with figure 8 pattern
7. dry part and place in oven at 400F for 1 hour and shut off furnace and let air cool to handling temperature.

My first part is pretty hard. I really don't want to put out $150 for a set of hardness files. Does anyone have a method for grossly quantifying the hardness using common place materials?

I've read where one could use 90% wood charcoal and 10% Barium carbonate (as an accelerator). I think that this is by volume (but it could be mass). I read where one should replace roughly 20-25% of the packing carbon/barium carbonate per run. I'll have to buy a couple of pounds of this material and see how it works.

I'm running a second test where I have different diameter nails to get some sort of feeling for the case depth. It is hard to find information on case depth vs. time and temperature for wood charcoal materials. Hopefully, I'll be able to qualitatively determine case depth by evaluating the toughness of these nails.

do you know how deep the case is? if you cut and polish a sample you should be able to see it. if not use some acid.

question: does the part really have to be tempered?

john.k · Nov 18, 2020

Cutting edges are normally tempered at 160-200deg C.....this toughens the edge,without reducing hardness......This tempering can be done in a domestic oven .

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