Help with 1084 heat treat.....

jaxxas

Well-Known Member
So working on nailing my heat treat process with 1084. I 'know' it is supposed to be easy but apparently I'm doing something majorly wrong.

My process.....

I cut 3 coupons blanks from fresh Steel Baron steel. Supposedly shipped annealed. I drilled a hole in each corner, notched 2 coupons for identification and then deburred. I did not do any normalizing or annealing!

I scrubbed up the coupons with soap and hot water, dried them and then painted them with ATP-641. Dried the ATP-641 with a heat gun.

Placed all 3 coupons in my electric kiln, ramped it to 1500 F with an ending soak time of 15 minutes. I pulled the first coupon after 3 minutes of soak time. Quenched with agitation in 125 F canola oil, and I just left the coupon to cool in canola while I tended to the other coupons.

Pulled the second coupon at 5 minutes into the soak and again quenched with agitation in slightly warmer canola oil. Again leaving it to cool in canola while I tended the last coupon.

Pulled the third coupon at 7 minutes into the soak and again quenched with agitation in canola oil at about 140 F. I also left it to cool in the canola oil.

So then I hit all 3 coupons on the grinder at 120 grit to clean up the faces, a secondary pass at 220 grit, dipping in water religiously to avoid heat buildup and then tested for Rockwell C hardness. Note I have not tempered these coupons.

I'm new to Rockwell testing but my 61.5 HRC test coupon reliably tests to 61 HRC. I think my Rockwell test procedure is OK?

I did 3 Rockwell tests on each coupon across the face.... (you can see the coupons below)

3 min soak coupon tested 55Rc, 50Rc and 58Rc

5 min soak coupon tested 45Rc, 49Rc and 53Rc

7 min soak coupon tested 40Rc, 58Rc and 58 Rc.


I was expecting something like 65Rc and I have no idea of what I'm doing wrong. I also would expect the readings to be more uniform across each individual coupon? I would certainly appreciate if anybody could point out my error, problems or issues, as I don't really know what to try next.

Another FYI, not sure it matters but my canola is fresh, 2.75 gallons and I do have some Parks 50 on order!

TIA!





 
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Doug Lester

Well-Known Member
Just one question. How thick are your coupons? The 1084 that Aldo sells does have a little chromium in it but it's still basically a shallow hardening steel, though not a shallow hardening as 1075. Your coupons might be too thick for the size of grain that it has to harden at the thickness of your coupons. You might have to reduce the thickness down to 1/8" or maybe a tad thinner and repeat the experiment.

Doug
 

Kevin R. Cashen

Super Moderator
Yes, while your post is really well done as far as providing all the needed information, the one thing missing is the coupon dimensions. Could be too thick, but could be too thin as well.
Also be careful to isolate as many variables as possible an then only change one thing at a time, e.g. change soak time but not quenchant, temperatures etc... just the soak time. When one variable doesn't affect things move to the next. It is more tedious but is the only way to eventually isolate and correct the issue.
 
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jaxxas

Well-Known Member
Thank you for your responses!

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"

I was cutting for 2"x2" coupons but was off somehow on one, I realized it when I did but didn't think it would matter. I will double check the rockwell test tonight.

I had read the composition from Aldo's site but I didn't realize that the chromium was a reason for concern. My Parks won't be here till next week so I think I will try 3 more coupons thinned to about .125" for my next test.

I appreciate your time and knowledge, my thanks to you both!
 

KenH

Well-Known Member
OK, You've now provided good test info and I agree, the Rc readings do seem like they should be closer together on the same coupon. One more question that "Might" affect (effect?) the Rc difference. How did you remove from oven to oil? Using a set of tongs? How did you grip the coupon? I would think if gripping coupon with tongs where the tongs gripped coupon would cause cooling before getting to quench oil and might well affect the Quench, thus messing up the Rc reading.

Kevin and Doug know their stuff - they're the folks I listen to... and Ed.... and Calvin..... and so many other folks on this forum.

Looking forward to your next test with 1/8" coupons - bet they turn out better.

Ken H>
 

J. Doyle

Dealer - Purveyor
There has been talk around the forums lately about this issue and Aldo's steels specifically. It has been the finding of many that Aldo's steels come heavily spheroidized and some higher normalizing heats and subsequent thermal cycles have been necessary to break up those spheroidized balls of carbon in the matrix in order to achiever the numbers that should be seen with given steels.

It has been interesting to note that the stock removal guys, which is basically what you're doing here with your coupons if I'm reading right, were the ones having the issues and not the guys that forged their blades to shape, which I think contributed to the erroneous claims that 'forged blades are better'. In reality, forgers weren't seeing the same issues because the forging heats were at sufficient temperatures to break up the spheroidized structures.

It would be interesting to see if you took the coupons to 1650 or so and soaked for 10 minutes then letting them air cool and then doing a couple heats to 1500 and 1450 respectively with air cools in between then heating to 1475, holding for 5 or 10 minutes and quenching would get you the numbers we should be seeing from 1084.

This would either confirm for yourself the findings of others or rule out one more variable.
 

jaxxas

Well-Known Member
OK, You've now provided good test info and I agree, the Rc readings do seem like they should be closer together on the same coupon. One more question that "Might" affect (effect?) the Rc difference. How did you remove from oven to oil? Using a set of tongs? How did you grip the coupon? I would think if gripping coupon with tongs where the tongs gripped coupon would cause cooling before getting to quench oil and might well affect the Quench, thus messing up the Rc reading.

Kevin and Doug know their stuff - they're the folks I listen to... and Ed.... and Calvin..... and so many other folks on this forum.

Looking forward to your next test with 1/8" coupons - bet they turn out better.

Ken H>

Yes I used tongs, what else might I be able to use? As I recall at this point when pulling 2 of the coupons my tongs were hiding the hole and I had to reposition a bit after the initial quench to hang the coupon from a wire into the tank. I believe it was the 3 min and the 5 min coupons. I could retest Rockwell opposite the hole? Might as well I plan on retesting rockwell again anyway.

My next test should be tonight or tomorrow night depending on how much life gets in way.

Thank you for your help!

Went back and tested rockwell near the hole and then the opposite corner to check 'tong' effect. I know I picked up 2 coupons with the tongs covering the hole, I think it was #3 and #5. I definitely have higher readings opposite the hole, maybe #5 was the one that I didn't cover the hole with the tongs!? I don't know for sure, but I certainly will know the next time!

coupon near hole opposite hole
#3 35.5Rc 59.5Rc
#5 43Rc 53.5Rc
#7 36Rc 55Rc
 
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jaxxas

Well-Known Member
There has been talk around the forums lately about this issue and Aldo's steels specifically. It has been the finding of many that Aldo's steels come heavily spheroidized and some higher normalizing heats and subsequent thermal cycles have been necessary to break up those spheroidized balls of carbon in the matrix in order to achiever the numbers that should be seen with given steels.

It has been interesting to note that the stock removal guys, which is basically what you're doing here with your coupons if I'm reading right, were the ones having the issues and not the guys that forged their blades to shape, which I think contributed to the erroneous claims that 'forged blades are better'. In reality, forgers weren't seeing the same issues because the forging heats were at sufficient temperatures to break up the spheroidized structures.

It would be interesting to see if you took the coupons to 1650 or so and soaked for 10 minutes then letting them air cool and then doing a couple heats to 1500 and 1450 respectively with air cools in between then heating to 1475, holding for 5 or 10 minutes and quenching would get you the numbers we should be seeing from 1084.

This would either confirm for yourself the findings of others or rule out one more variable.

I have noticed the talk of the spheroidized steel from Aldo though I didn't know it affected 1084, I'd heard about 52100. Can I retry your procedure with the same coupons or should they be new coupons? I'm certainly willing to give it a try as I have several bars of Aldo's 1084 and would love to find a solution.

At this point I'm only a stock removal kinda of guy. I hope to get into forging in the future. I have some space limitations to deal with and would also have to look at a hydraulic type press/hammer due to close neighbors. So for now I'm baby stepping it, I know I have an awful lot to learn but I'm enjoying it. Knife making is something I've been wanting to try since I was a kid, never really had or made the opportunity to do it, life kept getting in the way. Older now and better positioned I usually can find more time to play and I hope it will be something to keep me active and productive when I get to retirement.

Thank you for your help!
 

J. Doyle

Dealer - Purveyor
I would go ahead and try that procedure on those same coupons. I'd take them from the state they're in right now and heat them to 1650 and soak for at least 10 minutes then finish the steps like I listed and see what you get.

Let us know what you find out...I'm interested too.
 

jaxxas

Well-Known Member
So just to double check I re-tested my coupons on the second side, testing opposite the side with the hole. (I assume it's ok to test the second side after already having tested the first side?) Not sure I learned anything though. Readings are still inconsistent.


Second side results.....

3 min soak, coupon tested 58Rc, 48Rc and 62.5Rc, avg 56.2Rc, coupon is 2" x 2" x .2" (t-b)

5 min soak, coupon tested 52Rc, 38.5Rc and 52Rc, avg 47.5Rc, coupon is 2" x 2" x .2" (t-b)

7 min soak, coupon tested 53.5Rc, 49Rc and 39Rc, avg 47.2Rc, coupon is 2" x 1.7" x .2" (l-r)



First side 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"
 

jaxxas

Well-Known Member
I would go ahead and try that procedure on those same coupons. I'd take them from the state they're in right now and heat them to 1650 and soak for at least 10 minutes then finish the steps like I listed and see what you get.

Let us know what you find out...I'm interested too.


OK, I'll try to get it done tonight or tomorrow night depending on life. I'll definitely post up the results.

Thank you!
 

wdtorque

Well-Known Member
Jaxxas,
Neat stuff. You have some very knowledgeable folks participating here, I'm in for more results.
I liked what KenH mentioned regarding tongs. Might it be possible to put a wire or loop through your hole to handle the coupons with? To take the tongs out of the equation?
Appreciate your efforts. Dozier (not Bob)
 

jaxxas

Well-Known Member
Jaxxas,
Neat stuff. You have some very knowledgeable folks participating here, I'm in for more results.
I liked what KenH mentioned regarding tongs. Might it be possible to put a wire or loop through your hole to handle the coupons with? To take the tongs out of the equation?
Appreciate your efforts. Dozier (not Bob)


Thank you, and I thank the Lord for the knowledge people here are willing to share!

I like the idea of a wire loop, I'll give that a try on my next set of tests as I can only change a single variable at a time!

Thanks!
 

jaxxas

Well-Known Member
FYI Update


So far I have cut, drilled, notched and thinned the 3 new coupons to .125".

I have also normalized and annealed the original coupons per J.Doyle's procedure.

Hopefully I will get both sets of coupons heat treated and tested tomorrow night. I'll have to watch the temp of the quenchant.
 

Kevin R. Cashen

Super Moderator
The dimensions of the coupons will exceed canola oils ability to through harden this alloy, and yes that will be reflected on the surface, especially in the center of the piece.
 

jaxxas

Well-Known Member
The dimensions of the coupons will exceed canola oils ability to through harden this alloy, and yes that will be reflected on the surface, especially in the center of the piece.


Thanks Kevin.

Is that both the original coupons and the new thinned coupons, or are the thinned coupons still feasible?

Is this due to the chromium in Aldo's 1084? Would 'normal' 1084 be ok at these dimensions?

Will the Parks 50 be adequate for this type of quench?

Sorry for all the questions, but the more I learn the more questions I have.

I appreciate your help!
 

J. Doyle

Dealer - Purveyor
Parks 50 would definitely do it and would probably be ideal.

I'm not sure Aldo's 1084 has chromium in it in any significant quantity, does it? Manganese though should be around .70% which might get you close to full hardness on thinner samples with canola oil.

I would think that canola oil warmed to 125 F. or so would be sufficient for the 1/8" thick coupons but probably not full hardness on the 1/4" ones, especially in the center as Kevin noted. I would absolutely defer to Kevin's knowledge and position on the issue. I used canola oil very briefly, early on in my career and quickly ditched it for Parks 50 as I wasn't getting results I wanted with canola oil.
 

Kevin R. Cashen

Super Moderator
Thanks Kevin.

Is that both the original coupons and the new thinned coupons, or are the thinned coupons still feasible?

Is this due to the chromium in Aldo's 1084? Would 'normal' 1084 be ok at these dimensions?

Will the Parks 50 be adequate for this type of quench?

Sorry for all the questions, but the more I learn the more questions I have.

I appreciate your help!

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).
 

jaxxas

Well-Known Member
I don't really know what a significant amount of chromium would be, but it's .153.... :3:... here's Aldo's breakdown....

[FONT=&amp]Chemistry/Certification
Certification: C- .876 Si- .274 Mn- .803 P- .0100 S- .0040 Cr- .153 Ni- .037 Mo-.007 V- .004 W- .003 Cu- .037 Sn- .0030 Al- .006 Annealed Structure: 95% spherodized carbides[/FONT]

I'm going to continue with my current tests for now as I won't get my Parks 50 until next week after the holiday. I'm going to milk this learning experience all I can!:34:I will definitely post up the results.

John I assume that you are using a forge for heat treating and that you don't have any need of an anti-scale like ATP-641? I ask because canola oil pretty much strips the ATP-641 from the coupon, thus polluting the canola. I wonder if this is detrimental to life expectancy of the Parks 50? I suppose it is, but don't know any way around it. ATP-641 is water based and any water is necessarily driven off at hardening temperatures. Maybe the clay based compound isn't as detrimental as I suspect? Is there a particular volume or amount of oil you use for quenching? I have 2 homemade containers, one is almost a gallon, the other almost 3 gallons.

Lately I have been pounding the internet reading up on heat treating and quenching. I bought Kevin's ABS videos on grinding and heat treating. Definitely good information well worth the money. I found his hand drawn charts particularly interesting in the heat treating video. Education always has a price, be it school, books, videos or time spent gaining the experience.

Thanks for your help John.
 
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J. Doyle

Dealer - Purveyor
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.
 
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