Anyone sick of giving advice on 1095 yet?

K

KnifeMaker.ca

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Jan 1, 2009
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Well, I'm going to ask for help anyway. Trying to add 1095 HT to our offerings. We did some in the past and some of you may remember my thread with the unintended hamon line. That was queched in canola.

I decided to get a proper oil and hope for better results. I got Houghton Quench K - a 9 second oil like parks 50. First tests were with some O1 blades and they turned out great. Next was a 1/4" thick 1095 chopper and it looked great, but Rockwelled in the mid 40's.

Using ATP641 antiscale - into the evenheat at 1500 degrees - previously double checked with digital pyrometer - 10 minutes to equalize and ten minutes at temp. Out fast to the quench pail right below the oven - stabbed in quickly and then 'sliced' back and forth (not side to side) for 30 seconds before peeking (5 seconds - it's straight) and back in till hand cool. Scrubbed off the last bits of ATP641 and into the Rockwell tester.

It should be 65 or so (I'm not one to split hairs or infer tester accuracy beyond what may be there). It's reading consistently in the mid 40's

Did it again - bumped to 1525 soak. Same results.

Took a sample of the same steel (From Admiral) to make sure the maker hadn't mixed up some steel bars. Same result - mid 40's. Tried without ATP - RHC39 till I ground off the decarb - then 44.

Tried brine - hot water - all it would dissolve (table salt) - floated an egg (an old test I'm told) - got RHC just under 65 - and a crack. :eek: The crack may be because I didn't get the whole sample submerged -> uneven cooling.

Tried a piece of 1/8 1095 and quenched in the Quench K - just a hair under 65.

Is 1/4" thick 1095 just too darn thick to get under the nose in oil?

Suggestions welcome. By the way, this is all stock removal stuff.

Rob!
 
Strange, I look forward to see what others say...
Only thing I can think of that the 1/4" stock is not 1095 if it doesn't harden in brine at proper temp...
Emre
 
Thanks Emre

The crack is really not of much concern - pretty much clearly from uneven quench. It did harden in brine, but a huge number of makers harden 1095 in oil and I'm hoping to hear some of their (measured - not estimated) RHC results at the spine of 1/4" blades. I'll use brine if it's needed - but I was sure hoping it wasn't needed.

Rob!
 
KnifeMaker.ca said:
Thanks Emre

The crack is really not of much concern - pretty much clearly from uneven quench. It did harden in brine, but a huge number of makers harden 1095 in oil and I'm hoping to hear some of their (measured - not estimated) RHC results at the spine of 1/4" blades. I'll use brine if it's needed - but I was sure hoping it wasn't needed.

Rob!
Click to expand...

Oh sorry I misunderstood the first post, it did harden at the brine , sorry.
Then the only possibility is there is something wrong with the oil.
Did you preheat the oil or was it at room temp?
Emre
 
I have a heater on the quench tank that keeps it at about 115F. It seems to go up about 5 degrees or so for each blade I quench. (5 gals oil by the way)
 
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Have you tried bringing the temp of your oil up? I would not think that 25 Deg in temp would make that big of a difference but it might.. worth a try bring the oil up to 135 that is where my sweet spot is... good luck
 
Even using just the canola oil my 1/4" thick blades of 1095 all got extremely hard. I found the really thick sections along the spine were not as hard, but they were still hard enough to skate a sharp file across.:D I even completely dulled a couple new Nicholson files in the testing of this. Sorry I can't tell you actual RHC numbers or anything, but if a file can't bite into the steel, it must have gotten pretty darn hard I would think. Will a file skate over the blades you tested at 44 RHC or does it bite into the steel? I should bring a couple of my knives into you to get tested next time I come down to Cremona.
 
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I'm not familiar with the anti-scale you mention, but I used a black powdered type of anti-scale with 1095 one time and got the same results you did. The only conclusion i could come up with was the anti-scale coating was not allowing the 1095 to drop temp fast enough. I quit using it as it really is not needed anyway for 1095 and have not had any problems since.
 
denim said:
I'm not familiar with the anti-scale you mention, but I used a black powdered type of anti-scale with 1095 one time and got the same results you did. The only conclusion i could come up with was the anti-scale coating was not allowing the 1095 to drop temp fast enough. I quit using it as it really is not needed anyway for 1095 and have not had any problems since.
Click to expand...

That's interesting...I've never even tried any sort of anti-scale coating before and I haven't had any problems hardening 1095. Can the anti-scale coating cause the surface cooling properties of the oil to change? Maybe it's interfering with the efficiency of the oil?:confused: I don't even know if that's possible or not but I guess strange things happen sometimes.

Oops! Sorry, I guess it was already tried without the antiscale and still same results. I must have missed that part.:o
 
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The anti-scale compound comes off during the quench though (I'm using the same stuff as knifemaker.ca) so it shouldn't be a factor.

What is the fastest quench oil there is?
 
Thanks all

I have considered the oil temp may be too low, but a vapour jacket should result in blotches of hard/soft. This is even all around. - and 20 points low???

Yes, the antiscale was a suspect - till I tried without and got the same result. I also paint it on instead of dipping to keep it thin. Sure makes a difference in scale / decarb.

Randy, I can't do file testing. I've found I feel what I want to feel and it isn't necessarily consistent with RHC readings. Some guys are good at it but I'm not reliable at all.

Tomorrow is another day. I may try again without the antiscale and up the oil temp.

Rob!
 
I wonder if it would make a difference if you had some sort of high volume mechanical agitation instead of just slicing back and forth??? I would also be wondering if you ground into the 1/4" chunk halfway and did another rc test, even on the 1/8" I think it would be interesting to see.
 
Are you sure its even 1095? I'd think even an oil quench from a slow oil would give you something over 50 HRc. Are you using the proper setting for the machine (ask me how I know to check that)? Are you testing parallel sections on the big chopper? The tapered surfaces of the blade will give you results that are way off. Can you grind a tapered piece, quench it then break it to see how far down the taper the hardness went? IMS, its tough to get full hardness at thicknesses greater than 3/32". Of course there is a lot of retained austenite in 1095 that will make a quench to room temperature lower than you would think, but it would still be way above 44 HRc. As a last resort, you could overheat it to coarsen the grain then harden.
 
KnifeMaker.ca said:
Randy, I can't do file testing. I've found I feel what I want to feel and it isn't necessarily consistent with RHC readings. Some guys are good at it but I'm not reliable at all.

Tomorrow is another day. I may try again without the antiscale and up the oil temp.

Rob!
Click to expand...

I find that when I want to do a file test, I use a good sharp file and actually try to file the blade for a minute or two. Some people say to just skate the file across the blade once or twice really quick and see what sound it makes, but to me that is not adequate. If the steel is so hard that it won't file away with several hard strokes and ends up blunting the teeth on the file, that is when I call it good.;) That's just how I've always done my file tests anyways...:) Anyways, I hope you have better luck tomorrow.
 
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me2 said:
Are you sure its even 1095? I'd think even an oil quench from a slow oil would give you something over 50 HRc. Are you using the proper setting for the machine (ask me how I know to check that)? Are you testing parallel sections on the big chopper? The tapered surfaces of the blade will give you results that are way off. Can you grind a tapered piece, quench it then break it to see how far down the taper the hardness went? IMS, its tough to get full hardness at thicknesses greater than 3/32". Of course there is a lot of retained austenite in 1095 that will make a quench to room temperature lower than you would think, but it would still be way above 44 HRc. As a last resort, you could overheat it to coarsen the grain then harden.
Click to expand...

I have even quenched 1095 that I purchased from KnifeMaker.ca in used dirty motor oil back when I first started out and didn't even know I was supposed to use a faster quench. That 1095 still got glass-hard even in the motor oil.
 
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When you do a hardness test are you letting the blade cool down to room temp. I always get bogus readings and if I wait a little bit longer the hardness comes up. The complete transformation of the steel may not be happening until you let the steel cool down to room temp.

Also, the thinner steel came out with the correct hardness. Is it possible that your soak time is not long enough.
 
yeah, you said you could handle the blade but maybe they aren't completely cool to Mf... try room temp like zanderman said

doesn't sound like there is anything wrong with your quench though the interrupt can sometimes be a problem with thicker sections as the temp inside may re-warm the outside

probably you don't have 1095... Admiral sent me steel that would not harden in oil and charged me for L6 which will harden in air blast (thin sections), but the steel they sent me got very hard in water even in .230 chunks
 
edit that bit about the interrupt, just re-read your OP, 30 seconds should be plenty before interrupt, so if they are not above 60 rc at room temp you don't have 1095

have you done a side by side spark comparison with the thin 1095? (do this in the same state i.e. annealed)
 
I would SERIOUSLY doubt that your working with 1095

1/4 is no where near thick enough to cause problems even with a horrible quench medium

Admiral has a long history of shipping steels that are improperly catagorized. (8160 vs. L6, etc)

I can get a straight bar of 1095 3/8 x 1 1/2 fully quenched with parks #50 no problem


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if your absolutely sure that your steel is 1095 then my first thought would be that you normalized it to the point that it is no longer hardening properly.

you can actually get the grain small enough that the steel won't harden.

in that case, blow the grain up (1600F) then refine normally (I do three/four normalizations, 1450 soak for 5 min, 1400 soak for 1 min, 1350 soak for 1 min, etc)
 
Rob,
That houghton K quench isn't fast enough, you listed it as a 9 second oil, and 1095 is a 1 second quench. Sounds like it works fine on the 1/8" stuff which is not suprising to me, but to do the 1/4" you will need to get some parks #50. I know its almost impossible, but its either that or brine and lose 40% of your blades. I worked with 1095 for quite a few years after I started.
To all those who doubt that Rob is working with 1095, I will say that I found his results are EXACTLY what I would have expected, and I can say with confidence that I went through at least 1000 lbs of it.
Thanks,
Del
 
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