A moment of weakness - what the heck just happened?

R

Rob!

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Feb 9, 2000
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:confused: I don't do oil quenching steels. OK, well I've done a couple dozen O1 blades - and maybe a dozen oil quench damascus - but WE don't do oil quench heat treating. :rolleyes:

...except he asked so politely and was so understanding that I had little experience - and besides - what can possibly go wrong with 1095 on an 18" blade???

:foot: I said I'd give it my best shot. He normally does his own HT but the 18" blade wouldn't fit his oven.

The blade arrived with some interesting warp to it - that could largely be coaxed out, but minutes later would return to "un-coaxed". Oh Gawd, I am so far out of my depth here. I woke up in the middle of the night, certain I could hear something spontaneously going 'tink' on the kitchen table. :eek:

This is what came out the back end of my "and then a miracle happens" process. Can someone please tell me what happened here?

1095blade-007.jpg


The edge hardened to 64 - the spine to 50.

Process (largely related to starting warpage)
Coat in Turco so I don't burn the beast too badly
Normalize 3X - 1600 - 1550 - 1500 (5 min soak and air cool)
Stress releif - 1200 - 5 minute soak and air cool
Austenize 1500F, 5 min soak - quench in 150F canola (18 litres of it)
(note I did not say edge quench and there was no clay coat)
... thinking I'd screwed up I figured this was the time for multiple quench..

Austenize again 1500 while reheating canola - 5 minute soak - and quench - trying for faster, but the bucket is right at my feet only requiring a 90 degree turn and no steps. Heck, even gravity only goes at 9.8 m/s sq. :rolleyes:

I'm sure I was in the oil in less than 1 second and continued gentle stabbing and slicing movement with no side to side. I am pleased to report my eyebrows were undamaged, but I need a new face shield for the visor. (Last 2" of handle wouldn't submerge) - great wick! :D

I rockwelled above and below the line getting 50 and 64.

Flash temper at 350F 1 hr - temper 400F 2 hrs x 2 = RHC 57 edge (customer requested 56 - pretty close).

Now, I'm not unhappy with the outcome, but can someone tell me what the heck just happened?

I have a guess - but that's all it is. I wonder if the thinner parts of the blade got in under the nose while the thicker parts just didn't make it???

FWIW, we still don't do oil quench heat treats! ;)

Rob!
 
i think you guessed right.. unless the spine part wasn't at heat treat temp? otherwise it didn't cool quick enough..

by the way... 1095 is a shallow hardening steel..

if its straight... then i think it came out ok..

and if you want it to through harden...i woulda went with an oil hardening steel.....

but if your brave... you can water quench it... ( i wouldn't...unless you know how to slak quench it.. )

by the way...i've had the same result with many many W1 blades

Greg
 
Your guess would be my guess. From my understanding, canola can be a little slow for 1095. It likes a fast oil. Thus, while your thinner portions cooled quickly enough in the canola, it just wasn't fast enough for the spine/handle. You may have better success with Park's 50. I used canola for O-1 for a while before I got my AAA, and O-1 is more of a medium speed quenching steel.

--nathan
 
I would say the thinner parts of the blade cooled rapidly and quenched rapidly. The thicker part of the blade heald heat longer causeing it to cool more slowly. I have had this happen on large Bowies. It gives a nice edge quench look even though not intended, I also think tho I could be wrong that residual heat from the tang can help to keep the ricasso area from cooling at a rapid enough rate. Thus the thinner quench line at the ricasso area. Just my thoughts and I'm not that brite. May have worked better wit a fast quench oil like Parks#50 or AAA
 
sharpeknives said:
Just my thoughts and I'm not that brite. May have worked better wit a fast quench oil like Parks#50 or AAA
Click to expand...

I beg to differ. I susupect the first "stab" is really all you get - and the progressively warming oil throughout that stab would likely describe the line well. Your answer may be spot on.

I used canola because the maker said that is what he uses on 1095 and because this is hopefully, the last piece of 1095 I will ever heat treat. (though I may do some more O1 and even 1084)

Water was not an option after hearing "tink" from the kitchen table all night in my dreams.:(

Rob!
 
Thanks for the answers. I guess I'm left with two questions.

  • Is it repeateble?
  • Is it desireable?
of course the repeatable thing would require doing more 1095. Did I mention we don't do.... :rolleyes: oh - nevermind. :)

Rob!
 
I had a discussion w/ Mr. Kashen on another forum about quenching thick spined, shallow hardening steels in medium speed oil to get a line just like the one you have. He said he was able to get some pretty good lines as well. I havent tried it, as I have no way to heat a blade that thick. I figured a 1/4" spine or so, down to 1/32 behind the edge.
 
That same thing happened on a couple of my large bowie blades of 1095. I'm assuming the softer part is composed of pearlite. Would that effect be potentially a good thing on such a large blade? Maybe it would make it tougher. I used Canola oil on my 1095 as well. The smaller (thinner) blades I have done did not have that issue.
 
The picture looks like a blade that is just comming up to temp in my forge, that area is typically the last part to turn color. I wish I had a RC tester. Do you do custom RC testing as well Rob?
 
We Rockwell lots of blades for guys here. It's not a certified service - even my test block is rated +/- 0.5 - but it will tell if you got it right. No problem - only takes a minute.

Rob!
 
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