how can a average joe "heat treat" small parts?

[mozeppa]

i have a electric blanket...a gas stove...and a propane torch.

seriously tho,

is there a way a home do-it-yer-selfer can accomplish a decent heat treat?

guess i should clarify ....i want it hard...not brittle.


any help is appreciated.

[alrighty]

Yes,If you are working with an oil hardening steel such as O-1 and the part isn't too large.Post more details about what you are wanting to accomplish and you may have even more options.

[leftiye]

Brownell's sells anti scale powder. Use it in the first stage (hardening) or you will probly ruin the part. Heat steel orange hot (about 1300 degrees), quench. Second stage (tempering - drawing temper) polish item, use color or tempilaq to determine when tempering temperature is reached. Small parts, use a flat piece of steel with a handle locked in vise to hold part while tempering (or on top of fire brick). Different steels are quenched in different media when hardening. w1 - water, O1 - oil, A1 - air, etc.

[jmorris]

Kasenit compound is what I use but I am not sure it is made anymore. There are others out there though.

[smokeywolf]

You need to be more specific. What type of material, O-1, A-2, W-1? How big is it? Mass makes all the difference in the world. Never tried with a propane torch. If it's small enough you might be able to manage it with MAP gas.
If you're heat treating O-1 tool steel, fish oil is sometimes used as a quenching medium, but olive oil will do for a do-it-yourselfer.

[paul h]

A propane torch by itself typically won't get a part hot enough unless it is a very small part. But if you make a propane torch mini forge with either a coffee can and a refractory blanket.

http://cdn.instructables.com/F9K/Q6KU/HX42QYJR/F9KQ6KUHX42QYJR.LARGE.jpg

Or whittle one out of a firebrick

http://photos.imageevent.com/paleoaleo/knivesbladesandbladesmithing/websize/One%20brick%20forge%20fired%20up.jpg

Then you'll find your propane torch will nicely heat up carbon steel to hardening temperature.

[theperfessor]

The fundamentals of heat treating steel are really pretty simple. To harden steel you have to go through four basic steps:

1. Heat to austenitizing temperature, about 1500-1600F for most steels.
2. Hold at that temperature until you get 100% austenite.
3. Quench to form martensite.
4. Temper to relieve stress and toughen the steel.

How do you know when a steel is 100% austenite? It is nonmagnetic, when a magnet won't stick the part is ready to quench.

Most alloy steels require oil as a quench media to cool rapidly enough, some tool steels are air-hardening and harden up in air alone. Plain carbon steels require water or brine to cool rapidly enough to harden.

Steels with less than about .25% carbon won't harden unless extra carbon is added to the steel through solid state diffusion through the surface (case hardening or carburizing).

To anneal or soften steel follow the first two steps above and then:

3. Cool slowly to form ferrite.

The tools and equipment you use can vary from job to job based on the size and material composition of your part. The steps and basic processes are the same.

[JSnover]

is there a way a home do-it-yer-selfer can accomplish a decent heat treat?


any help is appreciated.

Yes! Describe what you're working on.

[mozeppa]

Yes! Describe what you're working on.

2 pieces of common steel 3/4" thick x 1-1/2" wide and 7" long that is all!

[smokeywolf]

2 pieces of common steel 3/4" thick x 1-1/2" wide and 7" long that is all!

"Common steel" might just mean cold rolled steel, which would require pack carborizing. jmorris mentions Kasenit in post #4. That is exactly what Kasenit is for. It imparts carbon to the surface of your part and allows you case harden low carbon steels. You need to know exactly what type and grade of carbon steel your dealing with.

And, that is a lot of mass to heat with a torch. I wouldn't even attempt that with acetylene. You need to make a friend with an oven.

smokeywolf

[DCM]

Why do you need to harden these, what will they be used for?? Would a thin case hardening do the trick for wear resistance?
The more you can tell us the better we can help.
Lots of good folks trying, but if you maximize the info the end result will be far better.

[Plate plinker]

I think this is part of the triple top secret project.

[bangerjim]

2 pieces of common steel 3/4" thick x 1-1/2" wide and 7" long that is all!

"that is all'???? That's ENOUGH! 7" long is getting pretty long for the average joe garage shop weekend guy to correctly heat treat. And common steel will NOT heat treat. You can case harden it, but results are not like true heat-treating OH or WH steels thru and thru.

I do a lot of HT'ing and use a 2500degree full vacuum furnace for stuff like that. You cannot get something that long heated up sufficiently with just a torch, even stuck in a brick or home-brew tin can thingy.

If you really need it, find a local shop that they can throw into a batch they are doing. But not mild steel!

Good luck.

bangerjim

[Frank46]

They have not made Kasenit for a couple years now. I believe the new product is called cherry red.

[Whiterabbit]

That's a big piece of steel. Only way I would try is surface hardening compound (kasenit) with heat from oxy-fuel or I might TRY a turkey fryer. But I doubt the fryer could get enough heat into steel .75" thick. Maybe on full doggone blast. That's just such a large piece to heat treat without a furnace.

[MaryB]

High pressure turkey fryer burner set on edge and attached to a tunnel of firebrick might do it... mine is 170k BTU. Might have to add a layer of insulation over the firebrick to hold in heat and a door with a vent...

[mozeppa]

i believe its hot rolled steel ...my steel supplier is telling me that cold rolled is more $ .....i'm cheap ...thats how i roll.

next, those 2 pieces are to be rails ...sort of...that a moving shuttle will ride between them...i thought with a lot of grease and hardened they wouldn't wear a great deal.

now i'm thinking that a piece of delrin on each side of the shuttle and skip the heat treat.

grind and polish the bearing surfaces and may still some grease just may be
the ticket.

[alrighty]

i believe its hot rolled steel ...my steel supplier is telling me that cold rolled is more $ .....i'm cheap ...thats how i roll.

next, those 2 pieces are to be rails ...sort of...that a moving shuttle will ride between them...i thought with a lot of grease and hardened they wouldn't wear a great deal.

now i'm thinking that a piece of delrin on each side of the shuttle and skip the heat treat.

grind and polish the bearing surfaces and may still some grease just may be
the ticket.
I think you would be better suited going with the derlin or HDPE strips.Hot rolled steel does machine ok but it is difficult to get a bearing finish without the appropriate machines and tooling.One more option is you could check into products that are already machined for your application.They aren't cheap but they are good and already machined.Lamina is just one company that makes cam keeper and guide blocks in a variety of sizes and steels from cast iron , tool steel, and bearing bronze with graphite plugs to lubricate.
http://www.daytonlamina.com/guide-blocks-and-keeper-blocks

[bangerjim]

Another vote for an interposing "slick" surface.

Hot rolled has a very rough, rather scaly surface if it has not been machined. Cold rolled is smooth right out of the mill.

I try to avoid using hot rolled for anything machined or precision! I pay the slight difference and always use CRS......much cleaner and far easier to work with in the mills and lathes.

Stop by a Woodcraft store. They sell rolls of "slick stuff" HDPE that will do the trick. I use it all the time on fixtures and jigs to give a tough yet very slick slide surface.

banger

[cwheel]

Are these are the parts you had on this forum asking if a machinist could make them for you ?? If so, and you want to harden without a furnace or anything special, those parts need to start off being made of W1 or O1 steel. W1 or O1 steel isn't cheap. Steel in that size isn't hard to come by though, try MSC supply, most likely they will have it in stock. Then, after machining, someone with a oxy/acet torch set with a heating tip ( #6 or 8 mfa ) can bring the temp up to a point where the part isn't magnetic anymore and quench. W1 quench in water, O1 quench in oil. Parts that big will need a very even heat as to not warp the parts. After a rapid quench the first time, parts need to be polished to see the color, heat to a straw brown and let air cool. All of this also depends on what these parts intended use is, if this heat treating would be suitable for your application. If you want more than this it's time to send the parts out to a pro and it isn't going to be cheap. If your " hot rolled steel " is 1018 there isn't much you are going to do with it at home.
Chris

[Geppetto]

One other consideration, "hot rolled" is a process, not a material designation. You can buy hot rolled 4140, or you can buy hot rolled 1008. They are wildly different steels in the long run. If you made a propane forge, you could heat treat that steel, but if its a mild steel such as 1020 or A36, you won't get much hardness without carburizing, as stated above.

You could also consider an appropriate piece of brass or bronze for the wear areas or possibly some cast iron of some time if you need something that will last longer than a polymer. Otherwise some teflon (PTFE) might treat you well for a wear situation.

[bangerjim]

Are these are the parts you had on this forum asking if a machinist could make them for you ?? If so, and you want to harden without a furnace or anything special, those parts need to start off being made of W1 or O1 steel. W1 or O1 steel isn't cheap. Steel in that size isn't hard to come by though, try MSC supply, most likely they will have it in stock. Then, after machining, someone with a oxy/acet torch set with a heating tip ( #6 or 8 mfa ) can bring the temp up to a point where the part isn't magnetic anymore and quench. W1 quench in water, O1 quench in oil. Parts that big will need a very even heat as to not warp the parts. After a rapid quench the first time, parts need to be polished to see the color, heat to a straw brown and let air cool. All of this also depends on what these parts intended use is, if this heat treating would be suitable for your application. If you want more than this it's time to send the parts out to a pro and it isn't going to be cheap. If your " hot rolled steel " is 1018 there isn't much you are going to do with it at home.
Chris



I have tried the oxy/acet torch heating approach in the past for large/long stuff that would not fit in my furnace. Things, especially long things, tend to warp severly when heated unevenly with a torch. You just cannot get the heat spread over the entire length well enough AND deep enough to bring the entire item gradually up to "glowing" heat, and the result was a 10" piece of 3/4x2" steel that had a 1/2" cruve in it when quenched in oil.

It really needs to be brought up COMPLETELY to the soak temp recommended for the grade of material being treated. AND then soaked at that temp for XX minutes to insure the internal temp reaches the necessary levels.

Heat treating of teeny weeny little gun parts and the such with a torch or home brew tin can oven is no big deal for the general joe-garage-shop individual, but large things like the OP is discussing are a "horse of a different color".

bangerjim

[hiram]

www.backyardmetalcasting.com

[DougGuy]

You won't do nothing with 1018 but waste your time, you won't even p1ss it off.

Next time you want to manufacture a bit of machinery, buy some machineable heat treatable steel.

[M-Tecs]

Depending on what type of wear surface you need industrial hard chrome plating MAY work.

[smokeywolf]

If the load on these rails is going to be too great for materials like Delrin and requires something with greater hardness, tensile strength or rigidity, you might try Aluminum Bronze. An Aluminum Bronze alloy of at least 8% aluminum will have good strength and hardness while still having a low coefficient of friction.

Aluminum bronze has reasonably good machinability and is widely used for bushings in outdoor and even in salt water environments. We used it extensively for bushings in rotating assemblies on the rides at Universal Studios.

smokeywolf

[oldred]

Another easier option if you want to use steel MIGHT be 4140HT (4140 pre-hard) which is 4140 alloy prehardened to about 28 to 32 Rc, still machinable but has very good wear characteristics due to not only the hardness but also the alloy itself.

Try MSC or SpeedyMetals for a source of 4140 Pre-Hard.

Also while the recommendation for Kasenit for hardening small parts is common unfortunately the Kasenit itself is not, it has been out of production for about 4 years now and unless you can find someone with a supply the stuff is simply not to be found anymore. Cherry red is easily found however and seems to work fairly good but whether or not it's as good as Kasenit doesn't matter much since it's the only thing left. I have heard there is a "new" Kasenit on the market without the cyanide but a quick search didn't find any, I suppose even if there is it's probably no different than the Cherry Red product.

[oldred]

Lot's of unknowns here, how much pressure rides against these things (heavy, light?) what type of material will it be mated to, etc? How about a brief description of what these things are and how they will be used, could it be that maybe you thinking over-kill here? No point in spending the money on hardening or surface hardening if it's really not necessary.

[DCM]

Lot's of unknowns here, how much pressure rides against these things (heavy, light?) what type of material will it be mated to, etc? How about a brief description of what these things are and how they will be used, could it be that maybe you thinking over-kill here? No point in spending the money on hardening or surface hardening if it's really not necessary.

Big +1 on that.
If it must remain under wraps just try it without treatment and see how it works.
If it doesn't work out you may need better materials and heat treatment.
I bet the professor could help and keep a secret.

[country gent]

3/4" X 1 1/2" X 7" your going to see twist and bow heating with a tourch and more so if not quenched properly. Allo of the steel determines heat and procedure to harden completly and fully. Also if its not a stress relieved steel its going to warp and twist more from internal stress also. Some alloies require a longer soak time at temp to harden. Another issue on parts this size is enough quench Oil or water to fully sbmerse and remove the heat with out "boiling" off. If youve never seen hot steel quenched it will scare the bejeebers out of you. Alot of smoke and some flame with oil and stem with water. There has to be enough volumne to the quench to absorb all the heat from the part with out reaching the flash point of the oil. Another is with out atmosheric controls scale and burning are issues. At work the parts in the old furnaces were wrapped and packed before heating to keep oxegon away. Still got some scale. the new oven was controlled atmosphere and those parts came out a silver gray. You might get away with a case hardening type of hardness. Pack part in metal box charcoal bone and leather heat to burn off and quench. Case hardening will give a .010 - .060 thick hard surface, this is what you get from the kassenite or Cherry red. A case hardening may be more doable in the home enviroment for you.

[leebuilder]

Average Joes can do anything with the right gear.
you must have the proper steel to begin with, high carbon steel is a great place to start, drill rod is nice, recycled metal like lawmower blades and cutters are wicked too.
I make two or more pieces, heat treating is hard on metal, be prepared.for failure.
Heat to cherry red, quench in 80W90 or used engine oil.
temper on a hot plate or stove. On medium high heat, heat part to blue gray then turn off element and wait till cool. Test you part and polish to uncover any cracks or flaws that will make you look stupid later.
any questions please ask.




there was agood write up about this.on the Brownells website

[MBTcustom]

The best way to DIY heat treat parts the size that you describe is in a coal forge. You're going to need a pretty big one.
At the end of the day, it's not worth it. It's cheap enough to send the parts out to have a professional do it.
These guys are local to me, but I think everybody should know about them. They charge me about $75 to heat treat custom dies and similar parts as I have need of them. Their ovens are totally atmospherically controlled, and the parts come out straight and true, not warped at all, and they return the parts with a tag stating what the final hardness was.
They do quite a bit of HT for Wilson Combat and other firearms manufacturers but their bread and butter is large runs of industrial parts.
http://www.colemanheattreating.com/

I think if you do the math, you'll find you're money ahead to use a company like this.

[Taylor]

yes---build a forge---132386 add a support,turkey fryer frame works good.Hair dryer for blower.

[ohland]

next, those 2 pieces are to be rails ...sort of...that a moving shuttle will ride between them...i thought with a lot of grease and hardened they wouldn't wear a great deal. grind and polish the bearing surfaces and may still some grease just may be the ticket.

I relish the thought of being ambiguous.

Ever consider linear shafting? You can get stuff in all sorts of diameters, lengths, and hardness.

Check ebuy or other sites. McMaster, Grainger, MSC....

http://www.thomsonlinear.com/website/com/eng/products/linear_guides/shafting.php

[BigEyeBob]

Do asearch on You Tube for "gas bottle forge" theres a couple of good vids showing how to make a gas heated forging oven from a LPG bottle

[firebrick43]

Holy dead cow(said in a Harry Caray voice). Some of you are way over complicating things and some are plain wrong.

If you want to heat treat small mild steel (aka 1018/a36) you need to add carbon. (Hot/cold rolled is a process not a type of steel) The cheap way for a home shop is charcoal pack case hardening. Old guns where typically made with mild steel and packed with charcoal, bone meal, and eye of newt. Place in a stove or furnace and then dumped in water with bubbles coming up. The bone meal, eye of newt and air bubbles are unnessessary if you don't care about the fancy colors/patterns.

Crush hardwood charcoal into a powder. Do not use briquettes for the pack! Small parts can be placed in a small iron(not galvanized pipe capped at both ends with a small hole drilled(as to not make a bomb. Pack the part and powdered charcoal in the pipe and make sure the part is well centered and not touching the side. Kasinite(not sold any more) or Cherry red(kasinite alter ego) can be used in this manner as well.

I then place the pipe( or a steel box for bigger parts) into the wood stove. I keep the pipe on top of the coals and keep it from being buried in ash. The stove should be going a fair clip. In the summer I use a charcoal barbecue grill and place the pipe down in the briquettes. Small thin parts are good for a couple of hours and larger parts may take 6 or more. Tongs are used to remove pipe and water pump pliers remove hot cap(they should have been just hand tightened) and the whole mess is quickly dumped into cold water. The surface is now hard and the core soft and tough(unless you left it in to long). If you want to temper it an electric baking oven can do so. There are time temp charts available, and part is dumped into cold water again to stop tempering process.

[detox]

PTG's instructions for heat treating one of their die bodies:

"Die body is made of the same material as used by RCBS and other manufacturers. Heat treating is generally not necessary as the die body will last a long time after cutting to the correct dimensions, as the body will then only have contact from the brass cartridge cases. However, if heat treating is desired, heat to 1650 - 1700 degrees F and then allow to cool slowly for 3 to 6 hours."

I guess you bury hot part in dry sand letting it cool slowly?

[M-Tecs]

Not sure why PTG is stating a slow cool of 3 to 6 hours. To do that you would just leave it in the HToven and turn the oven off. The lack of a quench indicates they are using some type of Air-hardening tool steel.

[firebrick43]

I looked up the ptg die blanks. They are 4140. 4140 requires a quench in oil and then a tempering process. The description you listed (it is the same description on the website) is wrong or a typo. That process is however almost verbatim for stress relieving 4140 not hardening it. 4140 is not a good home heat treat metal unless you consider owning a good electric heat treat oven within the realm of home shop(some guys do however). Also the description leaves out the most critical step of placing the part in a stainless steel foil pouch with a piece of paper(when it burns it consumes the oxygen)

o1 and w1 a long with case hardening is really the only steels that should be attempted in a home shop with minimal equipment. Even the large tool room where I work sends out 4140 to be hardened (we have the equipment) as it's not cost effective to devote the time/man power to do small batches.

[detox]

Not sure why PTG is stating a slow cool of 3 to 6 hours. To do that you would just leave it in the HToven and turn the oven off. The lack of a quench indicates they are using some type of Air-hardening tool steel.

Midways site lists steel as 4140 chrome moly steel

http://www.midwayusa.com/product/118810/ptg-do-it-yourself-die-blank-30-caliber-pilot-hole-7-8-14-thread




...

[M-Tecs]

Midways site lists steel as 4140 chrome moly steel

http://www.midwayusa.com/product/118810/ptg-do-it-yourself-die-blank-30-caliber-pilot-hole-7-8-14-thread




...
•Die body is made of the same material as used by RCBS and other manufacturers. Heat treating is generally not necessary as the die body will last a long time after cutting to the correct dimensions, as the body will then only have contact from the brass cartridge cases. However, if heat treating is desired, heat to 1650 - 1700 degrees F and then allow to cool slowly for 3 to 6 hours.

If 4140 the 3 to 6 hour slow cool would be an annealing step to make a hard die soft. http://www.simplytoolsteel.com/4140-alloy-steel-data-sheet.html

[Red River Rick]

...... Even the large tool room where I work sends out 4140 to be hardened (we have the equipment) as it's not cost effective to devote the time/man power to do small batches.

Having the equipment, and saying it's not cost effective to do the heat treating in-house, is another way of saying we don't have the people with enough knowledge to do it. Either in small batches or otherwise.

RRR

[firebrick43]

Having the equipment, and saying it's not cost effective to do the heat treating in-house, is another way of saying we don't have the people with enough knowledge to do it. Either in small batches or otherwise.

RRR

No,there is 40 acres under roof with hundreds of machines. They have three guys per shift that stay busy. They do a fine job of heat treating if needed in a hurry for a down machine. If it is needed in two or three days an outside guy does it. They don't have enough to keep a guy busy full time.

[oldred]

PTG's instructions for heat treating one of their die bodies:

"Die body is made of the same material as used by RCBS and other manufacturers. Heat treating is generally not necessary as the die body will last a long time after cutting to the correct dimensions, as the body will then only have contact from the brass cartridge cases. However, if heat treating is desired, heat to 1650 - 1700 degrees F and then allow to cool slowly for 3 to 6 hours."

I guess you bury hot part in dry sand letting it cool slowly?



Not sure what they are trying to do there but that process will stress relieve and SOFTEN the steel, it most certainly will not harden it! Hardening a piece of 4140 of that size is something that can be done with a torch IF you have the experience to be able to determine the proper heat range by heating color but even then it's a crude and "ify" process if maximum strength is required but it probably would be ok for something like a die that does not require high strength. Scaling however must be dealt with and anti-scaling pastes would probably work just fine for the inside of a die but I would expect to see some scaling anyway on the outside if doing this with a torch but in any case those directions are just backwards to the real process.

If an oven is available then heating to the 1650-1700 deg F is about right but the part should be wrapped in stainless foil with the paper as mentioned or coated with anti-scaling paste then it is brought up to temperature and quenched in oil (I use trany fluid), the part then is reheated to about 400-500 deg F and held for about an hour to temper it. The problem here is the bore in the die will undergo some dimensional changes during this process so the bore should be finish honed after the HT process. For what these dies are used for and the fact that they are made of 4140 and will be sizing brass I personally would just leave them as-is considering the difficulty of a proper heat treat for such a small gain.

[Red River Rick]

Stainless steel foils work great for "Air" hardening tool steels, where the quench medium is still air. The foil does not have to be removed in order to obtain the desired hardness.

However using stainless foil on "Oil" hardening tool steels is really a waste of foil. When you quench the parts in oil, you've introduced the part to an oxygen atmoshere and then when submerged in the oil, carbon forms on the exterior surface. So much for your scale free exterior, after so carefully wrapping it in foil.

Also, by the time you unwrap your "oil'" hardening part from the foil, your loosing critical time before it gets quenched. There's a reason tool steels have a "Upper Critical" temperature. And, the time it takes to get from the furnace to the quench medium is also important as well. Dilly Dallying trying to unwrap a little part is really a PITA.

RRR

[Geezer in NH]

I myself would take a community tech college course at the night school and learn what.

[andremajic]

i believe its hot rolled steel ...my steel supplier is telling me that cold rolled is more $ .....i'm cheap ...thats how i roll.

next, those 2 pieces are to be rails ...sort of...that a moving shuttle will ride between them...i thought with a lot of grease and hardened they wouldn't wear a great deal.

now i'm thinking that a piece of delrin on each side of the shuttle and skip the heat treat.

grind and polish the bearing surfaces and may still some grease just may be
the ticket.

Get 2 thin pieces of high carbon steel, like plane blades, cut them to the correct thickness with an abrasive disk, and then silver solder or weld them to your mild steel pieces? Plane blades are thin diameter, wide, long, good steel, and generally about 5 bucks each.

This way you'll have high carbon tough surface that you can grind flat with a granite tile and different grits of sandpaper, and the lower part will be mild steel that you can drill and tap.

I'd have to see a picture of what you're trying to do to be more help.

[257]

the cherry red does not work anywhere near as well as kasinet have used a torch to heat to a bright red then quenched in oil (small parts)