Soak Times for 15n20 and Cru Forge V

H

HuffHK

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Oct 28, 2013
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First off this is my first post after spending many hours on these forums and I would sincerely like to thank everyone who contributes to what in my opinion is a vast collection of useful information as well as a very entertaining community.

The primary purpose of this post is to get some clarification/opinions on heat treating a few different steels. I will attempt to stay on topic as possible but figure a small intro (especially since I’m new) may help.

I’ve made a few blades out of re-purposed truck springs that are everyday users (big, heavy, and ugly) that in my hand can do more work than some people do with a small chainsaw. This is specifically in a landscaping setting in Hawaii cleaning palm trees, pruning, clearing and other tasks. These blades are extremely crude and elementary with no heat treat to speak of (and prob damaging original RC and temper during grinding). They still run absolute circles around anything you can pick up in a hardware store or any production blade I’ve come across.

In an effort to make some “better blades” I am working on a batch of known steel via stock removal that I will be sending out for professional HT.

I would very much enjoy being able to do some forging and basic HT in my “backyard” shop.

Hopefully this question does not get interpreted as which is the best steel kind of discussion because I know that is a never ending merry go round.
Right now I’m looking at 1080/1084, 15n20, 5160, and Cru Forge V but my question may be more general. I’ve read enough to have a general idea how these are typically heat treated.

My basic understanding (please correct if I’m way off)
1080/1084: heat to its austenitization point and quench (no soak needed)
15n20: heat and soak ~10 min at least for best performance
5160: heat and soak 8-10 min but may be able to get around the soak by heating and quenching 3 times
Cru Forge V: Crucible data sheet says "Austenize - heat to 1500-1550. Equalize. Quench in oil." However, without naming names but someone who worked with the steel early on recommends “heat in furnace at 1500 for 10 minutes. quench in oil” (should I name names? Not sure what the policy or proper thing to do is here).

Question #1
If I try and use a more complex steel XXX than YYY but fail to fully capitalize on its additional alloys/elements am I really any worse off with the finished XXX product than a YYY finished product. Specifically, if I am not able to get a decent soak on Cru Forge V and I’m only getting say 90% of that steels potential would having the Chromium and Vanadium in the mix even if it’s not fully utilized be advantageous or detrimental to the end product over standard 1080?

Question #2
Can you partially create or imitate similar results by doing multiple heat/quench cycles if one is not able to accomplish a proper soak time like what has been suggested for 5160 with other steels (specifically on this list but also O1 comes to mind as it is popular and deep hardening *5160 being deep hardening as well)?

Question #3
1080/1084 + 15n20 Damacus seems to be one of the most common combos. HT recommendations I’ve seen seem to suggest doing a basic heat and quench (1080/1084 style). This leads me to infer that not much of a soak is required to get decent results from 15n20? For those of you that weld 1080/1084 + 15n20 (San Mai or Damacus) how do you HT?

I wish I had the time and resources to endlessly pursue these and many other questions I have by trial and error and blood and sweat and years of experimentation with a hammer in my hand (perhaps someday I’ll get there). In the meantime any nudges in the right direction would be greatly appreciated. Especially if anyone can share experiences working with these steels which have produced solid results.

Thanks in advance.

Happy blade making.:)
 
Lets look at it this way. If your car needs a few minutes to warm up so the choke will open, that will make it run better and go faster once you put it in gear. If you just turn the key and drop it in drive, it will go, but be sluggish and dump gas out the tail pipe. If that is the same to you, then the steel's soak time won't matter. However, if you want better performance, give it the time it needs to get ready.

The term "equalize" means to allow enough time for the steel to be evenly heated in all parts and thicknesses. This is usually a couple minutes.
No steel is damaged by a 10 minute soak at a controlled temperature.
Most simple low alloy steels will perform Ok with less that optimal soak times ( 5160, for example).
Nearly all high alloy steels ( especially ones with more than one carbide former ingredient) will loose something if not fully soaked to allow the alloys to go into solution.


Multiple heat cycles won't equal a longer heat soak. Compare it to walking 1 mile to the store. If you walk 1/4 mile, turn around, and go home and do the same the next day, you have walked 1 mile....but you never came even near the store.

Damascus mix of 1084 and 15N20 is a perfect match because they have about the same carbon content, and the nickel makes a bright stripe. In the forging and folding the carbon gets diffused to even things up a bit, but the nickel does not move. A shorter soak time is therefore suitable, as the alloying is already where you want it.
 
Thank you for the response Stacy. As usual your posts are insightful and easy to follow. What you said makes perfect sense.

Per your car analogy, lets say on one track you have a Ford Taurus that is all warmed up running premium gas with a fresh oil change. Track #2 you have a Ford Mustang. The Mustang is running pretty crappy and is not warmed up. Which one makes it down the track first? Or is it a photo finish and too close to call?

With all the research I've done I know that the common consensus is that the ideal starter steal is 1080/1084. If there is a steel out there that may have an edge in performance even if you are not able to fully capitalize on its full potential it would seem that if you could harness just a small fraction of that potential that it could be advantageous in the end product.

Has anyone tried heat treating Cru Forge V in a simple forge with little or no soak time?

Thanks again
 
Cru-forge V should HT in a forge just fine ( with care and proper flame adjustment). Cru-forge V is not a super steel, just a forging grade 1095 with a little chromium and vanadium to keep the grain small and deepen hardenability. You could call it "52100 light". It will make a blade just a bit better than 1084, but without some serious testing I doubt you could tell the two apart. It has .10% more carbon that than Aldo's 1084FG, otherwise they will make very similar knives.

The perfect steel for making a good blade with bare minimum HT equipment is 1084. It will outperform any other steel that requires a more elaborate HT if both are done with no soak in minimal forges.
 
1095 is a difficult steel for many to properly nail for heat treatment for a variety of reasons, however if temperature control is an issue you're likely to get more consistent results with 1084 (despite the fact that they appear so similar).

52100 and CruForgeV offer very few similarities, as the only noteworthy shared alloying element is chromium, both steels having very different contents of this. CruForgeV has a lower amount of chromium to avoid the chunky chromium carbides it produces, and a LOT of vanadium for a simple forging steel to increase wear resistance tremendously. Hand sanding alone proves this to be true.

I agree with Stacy regarding 1084 as a great starter steel, but even with the barest amount of patience and practice I think you'd be capable of handling CruForgeV with the setup you have - the steel was designed with the input of bladesmiths to be heat treated by folks with minimal access to advanced processes and materials and still deliver an improved product.
 
Use a pipe muffle in your forge, buy 3 or 4 "K" thermocouples (they tend to burn out) and a PID off of ebay.

At heat treat temps, the thermocouple should last a fair while, but I always had one in my waste oil forge which burned at 2300F all the time and it ate them up after a while, so you may not need 4 of them.

you should be able to find a PID for 30.00 - $50.00 shipped, that will tell you the temperature inside your pipe muffle. If you're worried about decarb, throw a sliver of wood in the muffle while the blades are in there, the burning wood will eat up some of the extra oxygen.
 
To add, the pipe muffle I used was 3/16" wall, 2" id and I welded two chunks of rebar onto it to make it sit off the bottom of the forge so that the flame would circulate around it.
 
Thanks for the additional clarification and info.

I was planning on some kind of pipe muffle so I especially appreciate the tip on welding it up to sit in an ideal location.

I would love nothing more than to get my hands on some of Aldo's 1084. However, when I spoke to him on the phone all he said was he was waiting for a shipment but no ETA... He is having a fall special on 20n15 which is why I initially included it in my list of possible alternatives (that and fact that it seems to be the #1 welding combo with 1084). I'm not looking to reinvent the wheel just trying to find a reasonable alternative to the "go to" beginner steel. I'll probably get a couple bars of the steels mentioned in OP, mess around and see what happens.

Appreciate the input.
 
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