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Gabriel James

An experiment in water quench

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So after reading some info about how my 1095 probably wasnt fully hardening in canola oil--- I decided itd be smart to order a small bar of W-2! Smart right!? 66% failure rate unless i did something wrong.

 

 

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2 1095 gyutos and a w-2 petty

 

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cracks after i got to 400 grit -- Decided to break and test since i had assumed to have failures in this experiement

 

 

grains from the 2 gyutos (petty survived)

 

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My process- I wanted to focus on getting a better Heat treatment so these knives are 100% stock removal to take that out of the equation. Cutoff wheel to general shape > grind bevels > Normalized 4 times (after the 3rd time they developed warps and had to reheat to correct) I then Clayed up the blades ( i think too thick still around 1/8") Reminder i do everything in Charcoal at the moment. Starting with the spine facing my bottom blast tuyere - i turn the air down and let the blades heat up the spine moving the blades in and out to do so evenly. Bring the blade edges up to 1400~ for demagnetization. Followed by a very scientific few more seconds with the air blast turned up a bit more checking the evenness of the heat with the magnet... Then plunge into a bucket of warmed water in this case for 2-3 seconds and into oil until its cool enough to touch*(thanks to the other grain thread i will start pulling it out and fixing warpage here instead of letting it get cool all the way)

 

I salvaged the chefs knives and turned one into a Petty Chef. But the hamon comes out looking like a hot mess- This is fully hand sanded to 3k grit and ultra fine scotch bright. It looks nothing like Wes' where the line is prominent. All of my hamons have looked like this so Im thinking its something im not doing right.. Over heating the steel before quench?

 

Needless to say i wont be water quenching any steel anytime soon. Also i took extra care to take out any stress risers and softened all the corners. My quench angle was into a pale so it wasnt straight down nor was it a full horizontal. So perhaps that caused the same crack to appear in both knives?

 

I ordered some parks 50 yest so i dont have to have as many more casualties !

 

Thanks for your time! Hope this wasnt to rambly to make out-- kinda groggy still

 

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Edited by Gabriel James

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Take this with a grain of salt since I don't have much more experience than you do, but straight water quench with 1095 is pretty risky. I do a lot of interrupted brine into oil with 1095, and have never cracked a blade. This is what I do if I am trying to create a hamon.

 

1400F is a bit low for 1095 I think. I go up to 1500F, and try to hold it there for a few minutes. However, I have a thermocouple in a gas forge, so this is much easier for me to do than with your coal forge.

 

I have nor worked with W2, so I have no advice there :)

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1400 is the critical temp--- 1390 i think actually where the metal starts becoming nonmagnetic... but i have to eyeball up to 1475-1500 if that part was hard to discern from reading =\

 

 

to clarify there are some questions i have

 

 

how does the grain look?

Water quench angle should be 100% vertical? does it matter?

What am i doing wrong,

How can i fix it

and does anything else in my process look out of the ordinary / can be done in a better way!?

Edited by Gabriel James

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So a few things.
The grain looks Ok from what I see.
Basically if it looks like sand or gravel its bad and if it looks like smooth peanut butter its good.
1095 is not great in water and really not in canola.
You have a lot of decarb on the outside of your hand sanded blade which is why it has all those marks over it.
If you just did stock removal doing 3X normalization is unnecessary.
It should come normalized and annealed.
So after heat treatment you should grind up to at least 120 before going into hand sanding and that should get rid of that decarb.

About temps.
Critical is above 1400, its like 1430-1440 but you need to be pushing 1500 to have your phase change that allows martensite to be made.
If you are using a charcoal forge I would suggest doing it at night or in the dark.
Build a fire brick box over the hearth. This will hold the heat.
Allow you to see the light in the blade and keep the heat more even.
Like you said, put the blade spine down and point out.
The point should be the last thing you heat because it is the thinnest and easiest to overheat.
Checking with a magnet is good, but looking for decalencence and recalecence is really where its at.
Knowing the color of the steel which to me is like the orange of a harvest moon.

http://cdn.phys.org/newman/gfx/news/hires/professorrem.jpg

basically if you have gotten above 1450 and there are no shadows dancing in the steel you are ready to quench.
as far as claying goes.
Thin your furnace cement till it is like yogurt....lots of food references here hehe.
Look at the consistency the japanese use in one of their videos.
When you use rutlands black smooth cement then thin it to that kind of consistency and lay your clay out the way the Japanese do it.
Lay in your ashi lines and then your main spine clay.
On a blade like the one you showed finished. I would lay ashi to about 2mm from the edge.
Then lay the spine clay about 1/3 down from the spine and undulate it a bit.
When the blade is quenched heat is insulated and pulled up the down the ashi lines which creates more activity.
With as much clay as you are using it is acting like a big heat sink and that's a possibility that you are just getting a straightish line.
1095 makes amazing fluffy hamon, big white habuchi and nice ashi.
Which you have to polish to a high grit but you have to get rid of that decarb or you are just polishing decarb.
This is a tanto in W1 closeish to 1095.
Wasn't polished to more than 2000

http://www.bladesmithsforum.com/index.php?showtopic=28861

Keep plugging away, you'll get it.

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Everything they just said, however I have had a 50 / 50 on quenching 1095 in water, I found that no matter that I did I could not get above that ratio and I believe it is the batch of steel I got. I have a 90% success rate quenching W-2 in water, my method is I heat the water to around 120 degrees this help prevent shock to the blade and yet allows it to get under the curve in the few seconds it takes to form martensite. But every now and then I live on the edge and quench at room temp.

 

Now something that some of you have failed to mention is brine water, I will say no more other than for you to go read up on it as every one has their methods so best to get a base knowledge first.

 

Last but not least I use Parks 50 for a lot of my work as it is very fast and very stable and yields a 100% success rate for me.

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I post HT ground with 80 grit to thinner dimensions--- unless the decarb is really deep or my Heat was overshot--- could i be etching too deeply? IDK why but i just realized-- I have been starting etch 5 minutes in 2:1 PCB water:acid then hand sanding reetch- repolish and so on....

 

ill go back and re read some more

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Etching wise, I use 1 part pcb (ferric chloride), 5 or 6 parts water, and 1 part white vinegar. Some will go wayyyyy less than that but that's what I have found that I like. Sounds like your etchent is way too strong. Also your etch times seem high. For hamons, I etch only for 30 seconds and polish. Etch again for 20 and polish, then increments of 5 seconds until I like what I see. All the while polishing between etches. To me, it seems your getting some weird alloy banding, which is a heat treat issue. But I'm not sure because usually the alloying banding is only around the habuchi.

Edited by Austin_Lyles

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thanks gents for taking your time to help me out -- i have some things in mind to try to try and get this ironed out. Parks 50 will be here in a few days and in the process of figuring out how to build a gasser among other process fixes

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I can't say enough good things about Parks 50. Wonderful stuff.

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Gabriel, you're going to wonder how you did without the P50! It is indeed wonderful stuff! 1095 and W2 both are very very shallow hardening, so you really do need a very fast quench. And as you see, water can be risky. I always recommend a brine solution over straight water, because the salt helps to break up the vapor jacket that forms around the blade in a water quench. Also, adding an extremely thin clay slurry on the entire blade helps to break up that vapor jacket as well. The only steels that I can actually recommend a water quench (Brine) are the Paper steels from Hitachi Yasugi. White, Blue. Their impurity count is low, and alloying low, to allow for successful water quenches. And just for future reference, actual critical temperature for 1095/W2 is around 1475F or so. The magnet will start to release from steel around 1350 on the way up in temp, and will totally not stick around 1414-1425. When the P50 comes in, tell us how you like it!

Edited by stuart davenport

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I got the p50 in just today! gotta hurry up and handle these 3 blades so i can start making some metal to quench :P 145$ for 5gal pale at maxim oil

Edited by Gabriel James

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