Am I Quenching Wrong?

[Jeff RP]

Hello! I’m brand new to iforgeiron as of about 15 minutes ago. I recently got into blacksmithing, I’ve always thought it was interesting, started with just making tongs and practicing my hammer control with mild steel until I thought I was ready to make a knife. I ordered some 80CRV2, I forged a few knives. They turned out okay, a little profile bro ding and they looked pretty good. I’m ready to heat treat them but I didn’t want to screw them up. So I used some scrap 80CRV2 (a few little 1”-ish triangles I hot cut off the end of the flat bar while forging).

I did about 6 hours of research (so many different recommendations!). i try not to take anything on the internet as fact until I do my own tests. I saw people say you could harden 80CRV2 in water, in canola and most people say a fast quench oil.  I don’t have any fancy quench oil (I ordered some but it’s not here yet). So I did a controlled test, i used a two burner propane forge (bought on Amazon) with a 4” diameter piece of steel pipe inside it (I saw it a few times in some you tube videos to prevent hotspots). I marked all the pieces in a distinct pattern with a punch before I heated them. I used a laser thermometer to measure the temp (1550F). I quenched one in canola oil at room temp, one in warmed canola oil (it was probably around 140F), one in warm water (about 100F) I also had one I didn’t quench at all.  The ones I did quench I dropped in small cooking pots then grabbed them out with tongs. Maybe 2min? 

Not a single one of the samples hardened… I really hope someone can help me figure out what I did/didn’t do to make that happen. 

[Latticino]

80 CRV2 should harden fine in 120 deg. F canola.  However, you shouldn't drop it in the pan until at least 15 seconds go by, and ideally use a large enough piece so the tongs don't cover up the part you are going to test.  How are you determining that the steel hasn't hardened?  Are you doing a break test?  How quickly did you get them in the oil?  Also, how long did you leave them in the forge at elevated temperatures (possibly you have significant decarb)?

[Irondragon Forge ClayWorks]

Welcome from the Ozark mountains. I have never used 80crv2 but from what I understand it is an oil quenching steel. If you do a search like this with your favorite search engine, you will get a lot of hits about quenching it. No brackets (Quench 80CRV2 site:iforgeiron.com)

[Jeff RP]

Oh, I got these hardness files I found on Amazon too. There are very few places that sell blacksmithing supplies in my area. Either that or they are just not very well advertised.

I had it at 1500 (fluctuating a bit because I’m trying to use a propane forge and the laser thermometer) for 10 min. Then I let them cool in vermiculite. Then I heated them up again to 1550-ish for about 7min. Then pulled them out and it took me a second or two to pick each up and see the markings, then drop them in the different mediums. 
 

I did drop them in, and then pick them out a few seconds later. 

[Jeff RP]

Irondragon ForgeClay Works thank you! I was able to find another thread where someone had almost the exact same issue. I read some of the suggestions given there and I will try them this week. I hope it works. I was hoping to give a knife to each of my brothers for Christmas. (Not that they would be amazing knives because they are my first few but still would be cool) 

[Jimw3326]

I pulled this off a steel supplier.80CRV2-Heat-Treat-7-20.pdf

[Latticino]

Hardness files can be unreliable if you potentially have a layer of decarb on the surface.  To check a test coupon for hardness I typically do a break (snap) test.  Pre-file a groove in your samples.  Harden, but don't temper all but one sample.  Place in vise with file mark just above jaws.  Cover with thin cloth and wear eye protection.  Snap with hammer (if it bends instead of snapping it didn't get hard).  Once you have established that your heat treating procedure is effectively hardening, remove decarb layer abrasively, then use your testing files to check.

Note:  IR thermal guns are not necessarily reliable at 1,500 deg. F either.  Ideally you should be looking for decalescence to identify the phase change before quenching.  Don't delay on quenching between taking out of the forge and dunking in quench media.  You don't have that long to miss the "nose", particularly for thinner stock.

Also, no need to anneal before hardening.  However normalizing, grain reduction, and a high temperature tempering pass are good for fixing grain and stress relief.

[Buzzkill]

80CrV2 is notorious for having a thick decarb layer after quenching compared to many other simple steels.  It has become one of my favorite blade steels, but you do need to compensate for the decarb layer.  If you do pattern welding with it this becomes very important if you want to see the pattern clearly.  I recommend a half a millimeter or so that you plan to take off in the final grind in order to make sure you remove it all.   FWIW I had a similar experience when I began using it.  Quench, file test, curse.   Higher temp, quench, file test, more cursing.  I finally gave up on one and was going to make it a display piece. However, after grinding a bit I got down to steel that skated a file nicely.   If you have some quenched pieces that you don't think hardened, you may want to grind a bit off the surface and check them again.

Oh, and if you want to see the effect visually you can etch the blade.  The decarb layer shows up as kind of a dull gray color. Once you get through that you should get the dark/black etch that you are used to seeing for hardened steels.