Help with 1084 heat treat.....

What I would do is make stepped coupons with each step wide enough to take HRC readings something a little less thatn 1/8" thick and then step up a couple of times to your .20" . What I actually do is make a wedge shaped (flat ground blade cross section) that is around .062" widening to .312" at the top and around 1.5" wide and then cross section it to Rockwell the end and determine depth of hardness. If going with the steps I would narrow your piece to 1.25"

The chrome should actually increase the depth of hardening a bit but it is still only 1084 and the chromium is not that extreme. P#50 should do the trick and is about as fast as I personally would ever go (water is for drinking in my shop and never for quenching).

That's great, I like the stepped coupon idea. I think that maybe this should be a first step whenever I attempt a new to me steel, so much more knowledge in a condensed format. I'll try to make up a couple of stepped coupons this weekend, I'll have to mill the steps but that shouldn't be an issue. So if correctly understand your 'wedge' you actually end up testing Rockwell on what would be the internal (depth) section of the blade? Brilliant, I'll need to get some thicker steel to try the wedge.

BTW where did you get those gloves you used in your ABS heat treating video? Also it's a great video. very helpful.

Thanks Kevin!
 
Here is the thinned coupons hardened. These were processed in as close to same manner as possible to the first batch. Using the same canola oil with possibly some minor variations in oil temp. I didn't have time to re-harden the original set of coupons, hopefully tomorrow.

Avg of both sides 61.1Rc


Avg of both sides 61.275Rc


Avg of both sides 62.65 Rc



Overall they are much better, higher rockwell results and fairly consistent, particularly the 7 min sample . Overall still a bit lower than what I was expecting. If nothing else I'm making progress. Possibly the Parks 50 will make up a few extra points of rockwell?

Edited to add, I used the tongs again to remove the coupons from the oven and to quench with, the tongs were gripping the bottom inside corner (in the pictures) of each coupon!
 
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I took photos with my phone of the break on each of the samples, not really sure what they mean.


3 minute


5 minute


7 minute
 
I'd use the biggest volume container you can for quenching (within reason....no need to go to a 20 gallon tank or anything like that). I use a 7 gallon ammo can with about 6 gallons of parks 50 in it.

I use my forge for heat treating some but mostly I use my salt bath setup. It's very accurate and scale is not really an issue. But when I use the forge, I don't ever use any type of anti scale compound either. I get a little bit of scale and decarb with the forge but it's not too thick and I account for that by leaving myself some material to grind away after heat treating.

I can't offer any help on what the antiscale compound will do to the quench oils. Your most welcome for anything I've offered that's helpful.

I guess I keep using my almost 3 gallon container and just fill it with half of the Parks 50 5 gallon bucket, just in case it gets contaminated.

I would love to check out and possibly play with a salt setup someday. I realize I'm a long way aways from any such thing at this point!

Thanks John!
 
I have been working with salts for almost 25 years and would say that for the most part they are a bit overrated by folks who haven't used them much. Very good results can be had with controlled equipment that is less expensive to set up, less costly to run and maintain, and won't try to take your face/head off the moment you lose concentration on what you are doing. That being said, much of my metallurgical research requires the salts. Either way do be aware that the steel needs to be alloyed for oil hardening in order to work properly with salt quenching. 1095, 1084, 1080, 1075, W2, W1 etc... will not respond well to salts, and that is why I sill keep a supply of Parks #50 in my shop.

I guess my biggest issue with folks seeing salts as "the ultimate" heat treat, is that many new guys feel that just spending the money on the equipment will bring them up to par with skilled experienced smiths. One can spend a million dollars on equipment but still the only thing that will make them good knifemakers is experience and countless mistakes that will build the necessary skills and knowledge; fancy equipment will only allow them to make a lousy knife quicker. The difference in salts is that this tool can not only expedite the lousy knife, it can kill you in the process. This is very evident in the number of folks with salts who are using them in ways that just make me scratch my head; dispencing with any advantages that could offset the risks. Then there are the guys who e-mail me to proudly say they have built the units but are asking what the salts are and if they can make them themselves using sidewalk de-icer, waters softener pellets etc... and wonder why I don't wish to continue the conversation. I have to explain that this is like telling me they have built a nuclear reactor and just wanted to know what this whole "noocoolar fizzun thingy" was all about before throwing the switch.

This is not to discourage you, that experience and knowledge I was talking about comes from exactly the kind of testing you are doing right now. But don't worry about the salts, the knowledge you will gain, combined with a good controlled heat source and Parks #50, will give you about the best you can get with 1084, and is the way I would do it in my shop, while my low temp salt tube stayed cold and shut off in the corner.
 
Just for clarity, in case I confused the topic, I'm using 1075, W2 and 80CrV2 almost exclusively and I use high temp salts for my austenitizing and quench in parks 50 and temper in the oven.
 
Jaxxas, I didn't read the entire thread, but it looks like your RC readings are getting better with the longer soak. Not sure if it has been mentioned here yet, but worth repeating if it was....

Aldo's steels are heavily spheroidized. His 52100 especially, but the 1084, and W2 seem to be heavily spheroidized (annealed). While this is great for machining, it isn't that great for austenitizing. You need longer than normal soaks to dissolve the carbides, which "can" increase aus grain size. I recommend for Aldo's carbon steels to normalize them first, then thermal cycle them, then harden them. Yes, technically the steel does come normalized, but after that normalizing, the factory did a "heavy" annealing to make them super soft. If you just try to harden them, you get less than satisfactory results. P50 is an awesome oil, it's nice to have engineered quenchants, but 130°F canola should do OK with 1/8" 1084 with this much Mn.

For example, with his 1084 this is my procedure: Normalize to dissolve carbides...1600°F for 10 minutes, allow to cool in still air. Carbides taken care of...check. Grain growth...maybe. Let's thermal cycle to nucleate new aus grains. 1550°F, air cool. 1500°F air cool. 1450°F, air cool. Now you have a steel that is absolutely ready to harden, and should be able to reach max RC out of quench now. Soak at 1500°F for no more than 10 minutes, quench. Should read 65HRC or better.

This problem seems to be limited to NJSB...because of the German mill he gets his steel from. Personally, I wish they were fine spheroidized instead of coarse spheroidized.

(edited to add a day later....I should have read the thread, John covered this quite well already!)
 
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So previously I had got the first original set normalized and annealed and I just now finished hardening and testing. They were ramped to 1475 F, soaked for 10 minutes per John's suggestion, quenched and cooled in canola. Note the 3, 5 and 7min labels are merely identifiers at this point, they all received pretty much the same soak in this secondary test, though they were pulled in the 3,5,7 order so there was some delay between each coupon, possibly up to a minute each. Here are the results....







And here are the breaks......

3 min


5 min


7 min


Pure novice here but to me the Rockwell results seem pretty much the same as the original results (below) with the exception of coupon #7min which is a smaller coupon and it was the last coupon pulled so it received a slightly longer soak. Note my graphic indicating where the tongs gripped the coupon. Any thoughts or interpretations are most welcome.

Original results.....
3 min soak, coupon tested 55Rc, 50Rc and 58Rc, avg 54Rc, coupon is 2" x 2" x .2"
5 min soak, coupon tested 45Rc, 49Rc and 53Rc, avg 49Rc, coupon is 2" x 2" x .2"
7 min soak, coupon tested 40Rc, 58Rc and 58Rc, avg 52Rc, coupon is 2" x 1.7" x .2"

Concerning the break, these were very hard to break compared to the thinned coupons I did yesterday which required not much more than a decent swing with a 1 lb hammer. I really had to lay into these with a 3 lb baby sledgehammer. Again a pure novice here but I think this means I didn't convert enough austenite to martensite? Please weigh in with your observations!

I just wanted to get these posted up for now. I will respond to the other posts later tonight, I have a slice of life happening right now!
 
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Just for clarity, in case I confused the topic, I'm using 1075, W2 and 80CrV2 almost exclusively and I use high temp salts for my austenitizing and quench in parks 50 and temper in the oven.

John, that is the nice thing about the high temperature side, the steel doesn't know what you used to heat it to 1475F-1500F it just knows if you achieved that heat. Obviously 1075 and W2 will do best in the #50, but you could get away with the 80Crv2 in the low temp salt quench.
 
Hard to tell exactly what the problem is. But we try to help. It may be the coupons are too thick for canola to harden this alloy well. My money is on the quench here (canola) is too slow to harden .2" thick 1084, which has a pearlite nose of less than 1 second. Try a water quench with one, this will tell us more, if it hardens. It may be your tongs have enough mass they're affecting the coupon heat. When I have done coupon testing, I make them with a "stick", and grab the stick with the tongs instead of the coupon itself. Another major variable to remember....make sure the decarb layer (not the scale layer...the decarb layer) is removed before testing, and make sure the test area has been polished to at least 220 grit, square to the diamond penetrator. Make sure your digital readings are correct on your kiln.

One thing at a time, we need to address the Rockwell readings and get them higher first. But the grain size looks a little large in the photos. I've seen way worse online, but it should look like a velvety smooth gray surface. You can break a drill bit or file for comparison.
 
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Just for clarity, in case I confused the topic, I'm using 1075, W2 and 80CrV2 almost exclusively and I use high temp salts for my austenitizing and quench in parks 50 and temper in the oven.

While you are at it would you mind telling me what stainless steel you use? Thanks,

Wallace
 
quenchant may be the issue. i have worked with Aldo's 1084 in 1/8" and got consistent Rc62-63 on a 2 1/2" wide 7" blade after a 325F temper, quenchant was Parks 50.
 
This is not to discourage you, that experience and knowledge I was talking about comes from exactly the kind of testing you are doing right now. But don't worry about the salts, the knowledge you will gain, combined with a good controlled heat source and Parks #50, will give you about the best you can get with 1084, and is the way I would do it in my shop, while my low temp salt tube stayed cold and shut off in the corner.


I'm a bit of a techie/tool nut, (ok a lotta bit!) just love that stuff. That said I have no idea of where this road leads. Can't see myself getting into salts anytime soon, possibly never. At this point I would be pretty happy just to reliably heat treat steel to it's full potential.

Thanks Kevin.
 
Jaxxas, I didn't read the entire thread, but it looks like your RC readings are getting better with the longer soak. Not sure if it has been mentioned here yet, but worth repeating if it was....

Aldo's steels are heavily spheroidized. His 52100 especially, but the 1084, and W2 seem to be heavily spheroidized (annealed). While this is great for machining, it isn't that great for austenitizing. You need longer than normal soaks to dissolve the carbides, which "can" increase aus grain size. I recommend for Aldo's carbon steels to normalize them first, then thermal cycle them, then harden them. Yes, technically the steel does come normalized, but after that normalizing, the factory did a "heavy" annealing to make them super soft. If you just try to harden them, you get less than satisfactory results. P50 is an awesome oil, it's nice to have engineered quenchants, but 130°F canola should do OK with 1/8" 1084 with this much Mn.

For example, with his 1084 this is my procedure: Normalize to dissolve carbides...1600°F for 10 minutes, allow to cool in still air. Carbides taken care of...check. Grain growth...maybe. Let's thermal cycle to nucleate new aus grains. 1550°F, air cool. 1500°F air cool. 1450°F, air cool. Now you have a steel that is absolutely ready to harden, and should be able to reach max RC out of quench now. Soak at 1500°F for no more than 10 minutes, quench. Should read 65HRC or better.

This problem seems to be limited to NJSB...because of the German mill he gets his steel from. Personally, I wish they were fine spheroidized instead of coarse spheroidized.

(edited to add a day later....I should have read the thread, John covered this quite well already!)

I caught this late yesterday, but I had company. I hoped that you would see that I had went through a normalization and an anneal process on the original coupons. My Parks 50 should arrive Wednesday. Woo Hoo!

Thanks samuraistuart!
 
Hard to tell exactly what the problem is. But we try to help. It may be the coupons are too thick for canola to harden this alloy well. My money is on the quench here (canola) is too slow to harden .2" thick 1084, which has a pearlite nose of less than 1 second. Try a water quench with one, this will tell us more, if it hardens. It may be your tongs have enough mass they're affecting the coupon heat. When I have done coupon testing, I make them with a "stick", and grab the stick with the tongs instead of the coupon itself. Another major variable to remember....make sure the decarb layer (not the scale layer...the decarb layer) is removed before testing, and make sure the test area has been polished to at least 220 grit, square to the diamond penetrator. Make sure your digital readings are correct on your kiln.

One thing at a time, we need to address the Rockwell readings and get them higher first. But the grain size looks a little large in the photos. I've seen way worse online, but it should look like a velvety smooth gray surface. You can break a drill bit or file for comparison.


Oh I like that, I'm making some of Kevin's stepped test style coupons tomorrow and I will make sure to include a handle stick! I'll make an extra for a water quench test as well. I'm grinding the coupons before Rc testing to 220 grit, as square as I can. They are down to bare metal.

How do you make sure your kiln temps are accurate?

On the grain size, do the thinned coupon's grain break look OK? I think I know the original coupon's grain break was pretty bad, they were very hard to break.

Thanks again samuraistuart....
 
quenchant may be the issue. i have worked with Aldo's 1084 in 1/8" and got consistent Rc62-63 on a 2 1/2" wide 7" blade after a 325F temper, quenchant was Parks 50.

Thanks Scott!

My Parks should be here Wednesday! Know of any vendors selling 'normal' 1084?
 
Aldo is the only one i know of. 80CrV2, which Alpha Knife sells as 1080+, sells for a similar price and heat treats well with basic oil quench. AKS says all of their steel is ready for heat treat out of the wrapper. for the water quench, make a 10% salt solution and have it at 140F or so.
 
As far as checking my own kiln, I have an analog needle thermometer, as well as a K type thermocouple with digital readout. Using those 2 in conjunction with the digital readout on the kiln itself, I can verify 1475F is exactly 1475F. (In all honesty, my readout may say 1475, but it's closer to 1472!!!) You can use table salt to check 1475, as it melts right at that temp. Pyro cones are another way, they're like little cone shaped thingys that melt at certain temps.

Scott mentioned the 1080+ from AKS. I highly recommend that steel as well. I used it on my first knives. Please ignore the HT data that Alpha Knife has listed for 1080+. It is completely wrong. 1575-1625 is way too hot of aus temp. That is approaching normalizing temp for that alloy!!!! 1080+ heat treats just about the same as 1084, I encourage a soak to help distribute the alloying a little. Aus temp should be 1475-1500. It is an awesome, tough steel, ready to harden as is. The only other real source I know of for 1084 is Tracy at USA Knifemaker (probably out of stock)...and I do believe it is the exact same 1084 as NJSB. If you have trouble with future attempts, try the 1080+. Aldo also has 80CrV2 (1080+), not sure how heavily spheroidized his 80CrV2 is, tho.
 
if you are able to control temperature this well, may as well take the plunge and try some O1. if you shop eBay or Victor Machine, you can find steel at good prices. both O1 and 80CrV2 do well with "Medium" speed oils, in a pinch O1 works ok with canola.
 
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