hardening 9260 help

D

dustfurn

Joined
Oct 2, 2007
Messages
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I am having a problem hardening a blade i've forged from what is purportedly 9260, which i purchased from Admiral Steel.

I will freely admit to being a novice, so take all of this with a grain of salt.

Basically, I seem to be unable to satisfactorily harden my blade. Cutting into 2x4 produces tiny dings and rolls (the rolls indicate to me that it is not too hard...it doesn't seem to be chipping) in the hair-shaving sharp edge.

As 9260 is an oil hardening steel, i first attempted a quench in vegetable oil. I slowly heated my blade to critical (measured carefully several times with a magnet...bringing up to critical and then cooling to room-temp, just so i had a good idea of what critical looked like), soaked at heat for about a minute, then quenched in room temp veg. oil. I then tempered in my oven for 30 mins at 400 deg. (the oven seems to be calibrated at least reasonably, as the temper color on the blade was a barely perceptible straw).

After sharpening and testing as described above, i figured i may as well try quenching in water...which i did as described above except in 90 deg water. I then repeated the tempering process and testing process...with the same results.

I then attempted to quench in cool water (~65 deg.) and didn't even attempt a temper. I re-sharpened and re-tested with the same results...this time the blade was less sharp...barely hair-shaving. Also, I took care not to put on too acute of an edge bevel. The blade geometry at the edge is similar to (actually a bit beefier) several other knives I have that cut into the 2x4 without any perceptible edge damage.

Please Help!
Dustin
 
dustfurn said:
I am having a problem hardening a blade i've forged from what is purportedly 9260, which i purchased from Admiral Steel.

I will freely admit to being a novice, so take all of this with a grain of salt.

Basically, I seem to be unable to satisfactorily harden my blade. Cutting into 2x4 produces tiny dings and rolls (the rolls indicate to me that it is not too hard...it doesn't seem to be chipping) in the hair-shaving sharp edge.

As 9260 is an oil hardening steel, i first attempted a quench in vegetable oil. I slowly heated my blade to critical (measured carefully several times with a magnet...bringing up to critical and then cooling to room-temp, just so i had a good idea of what critical looked like), soaked at heat for about a minute, then quenched in room temp veg. oil. I then tempered in my oven for 30 mins at 400 deg. (the oven seems to calibrated at least reasonably, as the temper color on the blade was a barely perceptible straw).

After sharpening and testing as described above, i figured i may as well try quenching in water...which i did as described above except in 90 deg water. I then repeated the tempering process and testing process...with the same results.

I then attempted to quench in cool water (~65 deg.) and didn't even attempt a temper. I re-sharpened and re-tested with the same results...this time the blade was less sharp...barely hair-shaving. Also, I took care not to put on too acute of an edge bevel. The blade geometry at the edge is similar to (actually a bit beefier) several other knives I have that cut into the 2x4 without any perceptible edge damage.

Please Help!
Dustin
Click to expand...

Hi Dustin, welcome to bladeforums!
Non magnetic is probably not high enough. I would go at least 50 or 75 degrees higher....
 
Was posting the same answer when the forums froze up for a bit. Yeah, curie temperature (non-magnetic) is usually a few degrees shy of the temperature at which you want to quench.

I would heat as Phillip said about 50-75 degrees higher, but if you're not using a thermocouple or a pyrometer, you have to be careful not to over heat and cause unwanted grain growth.

--Nathan
 
Yes , Phillip is right. BTW 9620 is a bit more sensitive to decarburization than other steels !
 
I do the file test after first quench to make sure it got hard, just run a file across the edge, it should slide right over without biting. I also try a scrap piece of steel first. I will make 3-4 rectangle blanks put them through the process, do the file test, break one in the vice, and then temper and break another to see how things have worked. If not happy I can retemper at a higher temp or start over.
 
PCRKnives said:
I do the file test after first quench to make sure it got hard, just run a file across the edge, it should slide right over without biting. I also try a scrap piece of steel first. I will make 3-4 rectangle blanks put them through the process, do the file test, break one in the vice, and then temper and break another to see how things have worked. If not happy I can retemper at a higher temp or start over.
Click to expand...

ok, you bring up the file test which is also something that has been confusing me...my edge definitely passes the "file test" (i.e. i run, without any pressure, a brand new file over the edge...it doesn't bite one bit)...
 
Edge may be too thin.
Decarb may be a problem,also.
Checking with a file only tells you it got hard- it doesn't tell you how hard.
The magnet only tells you it is at the curie point, not at austenitization point.
Stacy
 
bladsmth said:
Edge may be too thin.
Decarb may be a problem,also.
Checking with a file only tells you it got hard- it doesn't tell you how hard.
The magnet only tells you it is at the curie point, not at austenitization point.
Stacy
Click to expand...

Thanks for all the replies guys, however I am still having problems.

As a test, I cut off a fresh piece of the 9260, brought it up just a bit past curie point, quenched in cool water.

As a comparison i did the same with a piece of 1095.

Wow, what a huge difference! The 1095 is hard as glass...i can't make the file bite even with a fair amount of pressure. On the other hand, the 9260 is like butter in comparison.

I read that there is a max decarb depth on 9260 of 0.15mm, so i ground off a bit, just in case, but i couldn't tell any difference.

I just don't know what to do at this point...it would be a shame to not be able to use all this 9260...

Thanks,
Dustin
 
dustfurn said:
Thanks for all the replies guys, however I am still having problems.

As a test, I cut off a fresh piece of the 9260, brought it up just a bit past curie point, quenched in cool water.

As a comparison i did the same with a piece of 1095.

Wow, what a huge difference! The 1095 is hard as glass...i can't make the file bite even with a fair amount of pressure. On the other hand, the 9260 is like butter in comparison.

I read that there is a max decarb depth on 9260 of 0.15mm, so i ground off a bit, just in case, but i couldn't tell any difference.

I just don't know what to do at this point...it would be a shame to not be able to use all this 9260...

Thanks,
Dustin
Click to expand...

The 1095 doesn't have the extra alloying elements that the 9260 has, so it will harden from a much lower temp. Also, the 9260 may need a longer time at temp to get as much performance as you can from it. Heat the 9260 hotter, and try to hold it there for a few minutes at least, and see what happens.
 
1095 austenitizes at 1475F. 9260 is 1600F. HUGE difference.Especially if you are just guessing at it with a magnet (which only tells you that the temp is above 1400F).
Try the experiment with controlled parameters. The temps should be measured and the source should be controlled ,which is a HT oven. Do the 1095 at 1475F and the 9260 at 1600F. I bet they both get hard.
Stacy
 
Thanks Stacy. I was looking for that 1600 F number but couldn't find it !
 
If you let us know where you lived one of us maybe nearby with a HT oven and able to actually help you out with this. I know the best thing I did for my knives was make a good oven. Jim
 
Thanks again for the help/suggestions.

I finally got a piece to harden. I just received my Exetech, hight temp IR thermometer, which helped a lot in dialing in an appropriate temp. I soaked a 3 x 1 x 1/4 inch piece at ~1600 for two minutes, and then quenched in water. There was a much thicker layer of decarb than on the 1095, but underneath, it was quite hard.

Thanks,
Dustin
 
Interesting post , I have made a few swords and tanto from 9260 and I have not had any problems , As a matter of fact I am Clay tempering a tactical style wakizashi tonight ( ya-kire) you do have to get it a little hotter to produce a hamon . Some folks have problems with this steel ? Because of 2% silicon it will be very tough and hard to chip , it will bend rather than break or chip .it does have a decarb problem but, just sand it off a little and etch and hamon is not too bad , I thought it held a pretty decent edge . I learned a little trick which I will tell you . for clay use satanite 2 parts and 1 part of activated charcoal finely ground in mortar and pestal. Ac increases the surface area a lot and helps with heating and cooling effect. here is a little tanto I made , and a sword I will ht tonite I hope this helps . Hmmm I cannot post attachments sorry ??? Bubba-san you can email me at berryman@socket.net for pics :)
 
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Back in my fencing days my swords were made of 9260 .A good steel for that but in those days the steel was dirty so failures were due to that rather than the steel itself.
 
Irashaimase Bubba-san.

You may not have noticed, but this thread is four years old.

I like 9260 for tanto blades, but have never sought a hamon on it due to the higher Mn and the Si. Do you have any photos of a 9260 hamon?
 
bladsmth said:
Irashaimase Bubba-san.

You may not have noticed, but this thread is four years old.

I like 9260 for tanto blades, but have never sought a hamon on it due to the higher Mn and the Si. Do you have any photos of a 9260 hamon?
Click to expand...


Yes I do have pics , I guess I didnt notice the old post sorry .here is link

http://knifedogs.com/showthread.php?16916-Ht-treat-quench-9260-wakizashi&p=153435#post153435 I cant post attachments yet ,I need to have paid subsciption , I will soon . If you email me at berryman@socket.net I will send you pic of tanto
Youkoso irasshai mashita
 
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