Help with annealing hypoeutectoid steels (5160, 1075 etc) in gas forge and others

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coldsteelburns

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Hey guys, I was reading up on a recent thread just a few days ago on how to properly anneal hypereutectoid steels like 1095 using a gas forge. (It was about Ash annealing Hitachi white steel) Stacy gave some great instructions that I just tested out and they work great, the steel is much easier to work with than when it used to just heat it up then bury it in vermiculite. It was basically heating to about 1250F and letting cool to black then quenching in water and then repeat a few more times.

Well anyway I have been using quite a bit of 5160 steel from leaf springs and have had a helluva time trying to drill holes in it after putting in vermiculite. I also have a legnth of Aldos 1075 that will be seeing a lot of forging so I was wondering if you could help me out with a good process for Normalizing/thermocycling and then annealing, and then the best way to HT or Austinize n temper both of them. Also, since 1080 and 1084 or basically eutectiod steel, would there be a diff process for annealing those? I already know how to HT those steels but I'm looking for help with mainly 5160 and 1075, and if by any chance you could, I would like the same info for 52100, that would be great!!

Thanks for any help in advance and I hope I'm not askin for too much. Just a step by step for each steel would be great such as

-Forge at: X
-Normalize by doing X, X number of times
-Anneal by doin X, etc..
-Harden by Austinizing at X for X minutes
and temper and X, X times (I know this is obviously going to be different for what type of knife your making and it's purpose, but just a general temp for regular EDC type blades would be great.

Thanks a lot!! :)

-Paul
(Some of my knives etc.) www.youtube.com/Lsubslimed
 
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1st post here, so let me preface by saying that I have 0 (zero) practical experience making knives or heat treating so I can't give you a spot on real life recipe for heat treating 5160 or 1075 like you are looking for. I'm sure some of the incredible makers in this forum will be able to do that. I am going to be making knives very soon so I am doing my homework and these are some of the notes I've taken.

Hypoeutectoid and eutectoid steels will have pearlitic and ferritic grain structure when you anneal so you don't have to worry about excess carbon being deposited in the grain boundaries or as lamellar sheets like hypereutectoid steels, which need to be spheroidized. An anneal in ash or vermiculite with give good results.

Grain refining/ normalizing procedures are always a good idea, 2 or 3 reducing heats from 1600, maybe with a quench on the final normalizing heat for serious grain refinement. It is possible to reduce the grain size to the point that you will lose hardenability so don't go crazy. Skip this step at your own risk, but I'm sure you know that already from the sound of it. That's basically a note to myself lol.

Hypoeutectoid steels have less carbon so they need to be austentized a little bit higher, with little or no soak, 1525 depending on alloying elements. Quench in medium fast oil. Canola oil or commercial quenchant (best).

Temper at 375 for an hour, test the edge which should be hard and brittle and dial up from there for intended use. Maybe two more hours at 400 but if still too hard another two hours at 425. This in theory would leave the HRC in the high 50s 57-59.

If any of this is wrong please say so and say why, so I/ we understand correctly. Thanks.

Corey
 
One of the problems here is that eutectoid steels [~ .70 % C ] When HT'd resulting in near 100% pearlite is hard to machine. When steel is sold as "annealed" that may be the structure. You want spheroidized carbides which you could get easiest by a 'sub-critical anneal' ,about 1250F for a couple of hours .Spheroidized will be much easier to machine.
 
For annealing without a programmable oven, the best method for hypoeutectoid steel is to use the same procedures as for 1095. It doesn't need it for the same reasons hypereutectoid steel does, but slow cooling at 10° or 20°/Hr is not possible with a forge. Vermiculite will work with hypoeutectoid steel.

The proper metallurgical annealing procedure for 5160 would be:
Heat to 1525°F and then rapid cool to 1300°F. In this case for the term rapid, air will work fine. Then, cool at 20° per hour to 1200°. At that point the steel can be quenched to room temp and will be pearlitic.
Spheroidizing requires a much slower cooling and lower starting temps. Spheroidize at 1375°F, rapid cool to 1300°F, slow cool at 10°F/Hr for 6 hours. Quench to ambient. Another spheroidizing method would be to hold at 1250°F for ten hours.

The home method of doing 5160, or other hypoeutectoid, with only a forge would be to heat to non-magnetic, and then increase about two or three shades of red hotter ( if the forge has a pyrometer, 1550-1600°F). Pull out and air cool until it becomes magnetic again. Immediately stick it in the vermiculite tub and let it cool for 6 hours. Remove and quench in water. It should be pearlitic and reasonably soft.
You can also do a sub-critical spheroidizing anneal. Heat to 1600°F and air cool to black. Quench in water. Heat to 1350°F and air cool to black. Quench. Heat to 1250°F and air cool to black. Quench in water. Repeat 1250°F step two more times.
 
I highly recommend the use of a tempering muffle if you are tempering in an oven or other device that is not highly accurate.

Here is a thread I posted 4+ years ago in which I measured the temperatures inside a muffle and outside the muffle while tempering some blades.

http://www.bladeforums.com/forums/showthread.php/652704-Oven-Tempering-Muffle

The going straight into the oven without a muffle can see temperature fluctuations of almost 100 degrees F. The most important part of the blade is also the thinnest and will be the first area affected by the higher temperature. I also recommend a single temper of 3 hours when using the muffle.

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Good info 69 but we aren't discussing tempering in this thread. Though, I do think the muffle pipe works well in evening out temperatures in the forge, too.

This is what I do for MOST of my steels, regardless of the carbon content.

I set up the internal structure of the steel through thermal cycling...
- Heat to 1650F, air cool to dull red, oil quench(yes, I'm afraid to quench at the high temp:o)
- Heat to 1500F, oil quench
- Heat to 1450F, oil quench

Then do my humble version of a sub-critcal anneal/spheroidizing program. (Note that I do this from a hardened state.)
- Heat to 1250F-1300F, hold for 2hrs
- drop 100F/hr until 800F, oil quench

or the redneck version
- heat to a very dull red(in a darkened room), air cool to black, oil quench (repeat 3 times)
 
:cool: Wow thanks guys! Great info here :thumbup:

Cory: Thanks for the great info man, I'm glad that you popped your cherry in one of my threads, I'm honored ;) :cool: And thanks for the compliment on my knives! I really need to start finishing up some blades so I can post more vids and even some pics here. I tend to forge somethin out then rough grind it then start forging something else cause it's my favorite part of knifemaking. How long have you been making knives for? and do you have a YT channel or any pics of knives you've made? Welcome to the forums bro :)

Mete: I'm curious as to why you listed .7 carbon as a eutectoid steel? I always thought the 1084 was exactly eutectoid but 1080 and Cable damascus could be treated the exact same way.. Thanks for the info as well man :)

Stacy: Thanks brother, this was exactly what I was lookin for, and I was kinda hinting this thread's questions towards you :thumbup: :cool: lol Of course I always love getting info from all the great makers on this forum. Anway, If you had to only choose one way to anneal 5160 with a forge would you use the vermiculite way or the subcritical spheroid anneal way? And since 1075 is also a hypoeutectoid steel, would it be the same process as 5160 for annealing or does it only work with the spheroid annealing, also would you use a higher temperature for austentizing it just like you do with 5160 because of it being a hypo steel? And what about 1084/1080..? ? lol I really apologize for all the Q's, I just want to make sure I do it the right way because I'm more concerned now about annealing properly since all I ever used to do with all steels was the vermiculite anneal and I would just kill my drill bits and fail at drilling holes in 5160. I really appreciate it bro! :)

69_Knives: Thanks man, I never thought of using a muffle in the oven for tempering, I'll have to do that for now on, that's great info. I ALWAYS appreciate any and all infomation that is helpful. I wonder why more people don't temper in oil, there's no oxygen, and it's submersed in a fluid that is a consitant temp all around as long as you do it properly, I think.. I'll have to start a thread on that lol, thanks man :)

Rick: Thanks alot brother, that really makes me feel better and less anxious knowing that you use the same annealing technique for all of your carbon steels, because I know you know what you're talkin about since you make superior blades. I'm really glad you chimed in! :thumbup: :thumbup:

Thanks again guys! :)

(Also, anybody else reading this post, please feel free to chime in on the questions above as well :D ;)

-Paul
(some of my knives etc.) www.youtube.com/Lsubslimed
 
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coldsteelburns said:
:cool: Wow thanks guys! Great info here :thumbup:

69_Knives: Thanks man, I never thought of using a muffle in the oven for tempering, I'll have to do that for now on, that's great info. I ALWAYS appreciate any and all infomation that is helpful. I wonder why more people don't temper in oil, there's no oxygen, and it's submersed in a fluid that is a consitant temp all around as long as you do it properly, I think.. I'll have to start a thread on that lol, thanks man :)[/url]
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Probably because oil is flammable at the worst, and smokes, at the least.

If you quench in oil and temper in your home oven you'll want to be sure that you clean all of the quenchant off before tempering. I'm not sure if "I O No" will cut it with the wife if the house smells like burning oil when she gets home from bowling Saturday afternoon.
 
Cory: Thanks for the great info man, I'm glad that you popped your cherry in one of my threads, I'm honored And thanks for the compliment on my knives! I really need to start finishing up some blades so I can post more vids and even some pics here. I tend to forge somethin out then rough grind it then start forging something else cause it's my favorite part of knifemaking. How long have you been making knives for? and do you have a YT channel or any pics of knives you've made? Welcome to the forums bro
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Your knives look like sweet little cutters!! And I'm glad someone made the joke about popping my cherry lol. My experience is limited to having re-ground some kitchen knives that my mom was getting rid of on my dad's bench grinder back when I was 14 or 15. I used a cut up and shaped axe handle for the scales, lol! Don't know where they are now though... I have loved all sharp bladed things for as long as I can remember, and I am modern fencing coach so I am also around kids who love swords and bladed things also... Currently I am struggling to justify the start up cost to build a forge and get some minimal tools together. Don't have an extra 300-400$ in the budget right now for a hobby- as much as I hate to admit it. On the bright side I have already built myself a burner so I don't have to worry about that! And I hope I said something that was useful before haha. I have read all the stickies about 10 times each. Thanks for the warm welcome!

Corey
 
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Coldsteelburns - Understand that the eutectic temp given in various books can vary ,in fact there may be more than one in the same book !! It's measured in a laboratory with specific alloy .Think of it only as a guide not an absolute.

Muldoon - I was a fencing coach back in my early days .A great game ,too bad it's been used mostly in movies etc. I was at it for many years of enjoyment.
 
Mete, don't hesitate to get back into it. Lots of great fencing clubs in NY. I know guys in their 60s and 70s still competing at a national level. Its good fun for all ages.
 
In my teens, I acquired a set of nice epee foils, jackets, and masks. I borrowed some fencing books from the library of the local college and studied fencing with my best friend, Rick. Heavily influenced by Errol Flynn and Guy Williams (Zorro), we became fairly good at fencing ...... as far as we were concerned.....though we probably would have been kicked out of any formal competition. We wanted to practice in the high school gym, but the principal said he wasn't sure it would be allowed. So, we formed a fencing club...with two members. That gave us access to the gym for practice, just like the other intermural groups. We would use the basketball court double side lines to fence along most of the times, but when we wanted a bit more fun, we would fence up and down the bleachers. Rick was a very good gymnast, and would occasionally do backflips from the lower bleachers to the gym floor as a disengagement tactic. Before long we always had a good size group of people watching.
I sold the gear a long time ago, but still remember the enjoyment of using a sword in fencing.
Parry - riposte - parry - lunge - touché!
 
For the main concern - drilling holes, I found it is important to use at least good cobalt drill bits, carbide is even better. I always drill holes with a variable speed hand drill at quite a low rpm.

The key to drilling holes successfully in any material is matching rotational speed with pressure applied and not stopping until you are finished the hole. Blade metal will work harden as you drill through it so if you stop half way through the hole and try to restart it, it will be much more difficult to get started again.

As for annealing, If I ever wanted to anneal something, which wasn't often, I would heat to I guess around 1600F in the forge, shut the burner off and cover it with kaowool, leave it there till morning.

My process for 5160, 1095, 1084, 52100, Forge, normalize 3x, for the 5 series, heat to just past decalescence and hold there for 5 minutes, quench. 1084, heat to just past decalescence and quench, 1095, heat to just past decalescence, soak for 5 - 10 minutes, quench.

Learning to watch for and identify decalescence was probably the most important aspect I could have learned in terms of heat treating in a forge.
 
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Thanks Corey, yes you deffinitely said something useful :) and no problem, like I said, it was an honor poppin ur cherry :p :D LOL keep us up ta date on any knives you make one you get ur forge up and runnin. You can easily make a paint can forge that you can forge, forge weld, and HT in with a good burner :) :thumbup:

Thanks a lot guys! I really appreciate all the help, I feel much better about goin about the whole HT process now.

69_knives: I am getting a lot better at noticing decalescence now that I actually have been HT-ing more often in the dark. I was mainly lookin for recalescence during the daytime, which can still be pretty hard ta see, but it is easiler than decalescence in the light.

I also never took into account the work hardening while drilling, especially the 5160 since it can air harden as well, thatnks for that tip. I actually have problems drilling through Aldos spheroidized stock as well, I have a drill doctor which only works for reseting the angle on the drills, but I still have to take 'em to the bench grinder to make the part behind the cutting edges lower than at the actually edge, if that makes sence lol.. anyway, I just seem to suck really bad at drilling, even at slow speeds and good pressure on my HF drill press, that I know a lot of other makers use and are able to drill and greatly skeletonize their tangs using normal bits (I'm pretty darn sure about the normal bits at least). I am broke so I can't throw out bits after just a few uses and buy more let alone cobalts or especially carbides. But I shouldn't need those with the soft stock from Aldo, I even have a hard time drilling through mild steel at times.. but anway that's another thread, sorry man lol.. and thanks for the help! :)

Also, am I the only one here that doesn't fence? :( lol

Take care guys

-Paul
_______________
(Some of my knives etc. www.youtube.com/Lsubslimed)
 
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coldsteelburns said:
I also never took into account the work hardening while drilling, especially the 5160 since it can air harden as well, thatnks for that tip. I actually have problems drilling through Aldos spheroidized stock as well, I have a drill doctor which only works for reseting the angle on the drills, but I still have to take 'em to the bench grinder to make the part behind the cutting edges lower than at the actually edge, if that makes sence lol.. anyway, I just seem to suck really bad at drilling, even at slow speeds and good pressure on my HF drill press, that I know a lot of other makers use and are able to drill and greatly skeletonize their tangs using normal bits (I'm pretty darn sure about the normal bits at least). I am broke so I can't throw out bits after just a few uses and buy more let alone cobalts or especially carbides. But I shouldn't need those with the soft stock from Aldo, I even have a hard time drilling through mild steel at times.. but anway that's another thread, sorry man lol.. and thanks for the help! :)

Take care guys

-Paul
_______________
(Some of my knives etc. www.youtube.com/Lsubslimed)
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Do you have problems drilling through mild steel with a brand new bit?

The reason I ask is it may be your sharpening technique if you don't have any problems with a brand new bit. If you do, then it is something else besides bits and material. drill speed to fast, incorrect feed speed... Just trying to help you narrow down the problem.

I know HSS bits are pretty resilient to heat but a stone grinder can heat up a little piece of metal so very fast that it may be softening your bits.

I have only ever sharpened bits on a belt grinder with a 150 grit belt and they generally cut like a hot knife through butter afterwards.

Some of the guys at our shop are pretty abusive on bits and our belt grinder is a monster 3x132, 5 HP that you can almost smelt steel with if you got carried away so if the bit needs a lot of work I will turn it on then off so it isn't turning at Holy Shit! speed and won't heat up the bit too much, plus keep a container of water for dunking in to keep them cool... if it only needs a touch up I will let it roar at full speed and just do a quick touch on both edges and it's done.
 
bladsmth said:
In my teens,
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??! Stacy, I thought you were a blade smithing supercomputer assembled from steel scraps, grinding dust, and metal filings! I used to do lots of that stuff also haha. My high school soccer coach used to call me Errol. Fencers and knives... I really am in the right place lol.

69_knives thanks for bringing the conversation back to the shop- I have often wondered how much benefit there is in performing a complex metallurgical heat treating procedure like spheroidizing. Is it really worth it when we only have to drill maybe 2 or three pin holes and maybe skeletonize a full tang a little bit?
 
Muldoon,

Personally I don't think it is necessary to go through all that just to drill a few holes.

I've not made many knives in the past few years but I promised somebody a hunting knife a while back so I am making that one right now.

I thought I'd better put my money where my mouth is so I recorded a video of drilling the holes and will post the link when it is finished uploading.
 
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