2 White steel laminate blades

R

running bird

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Sep 29, 2015
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I’ve been working on these two blades on and off for almost a year now. I finally got them to the exact finish I’ve been trying to achieve. I have some curly maple scales with white G-10 liners I’m getting ready to fit to these blades. As soon as they’re done I’ll be sure to post pictures here.

Pictures: https://imgur.com/a/GmKTI83

This was my first time working with white steel and it was A LOT of fun fun getting to see the structure of these blades, and how they polish/etch compared to other steels I’m used to working with. I mostly work with Aldo’s 1075, focusing on hamons. The steel has a very plain look to its structure when its etched and polished, mostly turning a cloudy in the hardened area and that’s it.

But with white steel #2 when it’s polished and etched the structure of the steel starts to stand out. It has a swirling/waving/fuzzy grain structure. At first I assumed I had over heated the steel causing grain growth. But I noticed that when other people bring white steel (and blue steel to a greater degree) to a high finish it has this same effect. I would guess that this is from the iron sand Hitachi uses when manufacturing their steels. In a recent post on the Carter Cutlery Instagram page they showed a close up of the finish on some of their white steel blades and I noticed it there as well.

It was also really surprising how the carbon diffused into the mild steel cladding. These blades were only stock removal so I didn’t think there was going to be enough time for that to happen. But because of how thin these blades were during the HT it must have made it show the very little amount of carbon that did move. On the drop point blade just enough carbon moved to the cladding on both sides that it formed a very faint auto hamon. A similar hamon also showed up on the sheep’s foot blade but it was much more shallow and went away after enough grinding.

Both these blades are paper thin behind the edge and have an amazing edge flex, resisting breaking and bending. I think this makes them the perfect geometry to fully use the properties of white steel. They’re going to be amazing slicers if I had to go off of what they did to my fingers and hands during all the polishing.

I got some blue steel #2 laminate and homogenous white steel #2 back during the the holidays. So I’m really looking forward to seeing how the structure of blue steel compares to white when polished and etched the same way. I’ve already started to try out forging some of the homogeneous white steel. It’s a little stiff under the hammer but that might mostly be because I’m afraid of giving it too much heat and ruining it.

Any input on experience with forging white steel or knowledge of its structure would be awesome.questions and comments about my blades or process are always welcome too,

Kevin
 
3gEA7Ka.jpg


There you go!
 
Both of these are mild steel laminate, not sure of the exact mild steel hitachi uses.

These were the last blades I used my gas forge to HT. I first normalized them by heating them to a shade above critical, which to my eye looks like a very dull orange. Then let them cool to black. I heated them back up the the same critical temp for the quench but held there for 5min.

That was probably the most stressful 5min in my life. I really wanted to HT them the best I could so I set a stop watch for 5min and didn’t look at anything but the forge to keep my eyes from adjusting to something else. I kept moving it in and out of the fire to keep the shade from changing too much. As soon as the alarm went off the blades when right into an interrupted quench (1 sec in warm water, then hold in very hot Canola oil). I tempered them at 375 for 1hr

It was the best HT I could possibly do at the time, and I think it turned out very well. Certainly not as good as if I had my Evenheat but not bad. I did a lot of edge flexing to make sure there wasn’t any grain growth or exsessive stress and I wasn’t able to snap the edge.

Now that I have my Evenheat I’ll be able to fallow the data sheets that came with the steel exactly and come up with a much more consitant HT.
 
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Thank you very much, that’s a lot of very helpful information.

I’ll shoot you an email later today when I get the chance,

Kevin
 
So obviously from pictures alone it's impossible to say for sure, but I would be somewhat concerned by the clouds in the steel in both blades. White steel is extremely shallow hardening stuff, and I wonder if you didn't only get the very edge hard on both (which appear to be finishing out as hardened steel should). I have had similar clouds appear in the edges of white steel blades, and the cloudy sections are always soft. How did you finish these?
 
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I'm also concerned about the 1 sec quench in water and then to oil, thinking - did you check the hardness?
you want to check the hardness when the edge is ground down to .03-.04 or when the core begins to get exposed.
you should be able to cut steel with that edge and even chop a small nail with not damage or deformation.

in almost a hundred laminated blades including the mild steel ones you are using, I've never cracked a blade in straight water and I've never quenched in oil.
 
When I first hardened theb blades I did check with a file and it skated off like glass. The cloudiness made me believe that I overheated the steel when I quenched because of this. The edges are very springy currently and do not take a bend. I did a lot of looking around after that to see if anyone had the same experience and found that other people who took white and blue steel to a very high polish found the same cloudiness. If I’m allowed to link a post from another forum I could show where I saw this.

That’s the extent to which I can check the hardness, I don’t have a Rockwell test machine. The edges are extremely thin. I do not know exactly because I do not have calipers, but the area directly behind the edge is just as thin or thinner than paper.

I could add some more close up pictures of anything else on the blades if it’s needed.
 
Unfortunately, a file is only going to tell you whether the very edge is hard (and yours appears to be), and a rockwell tester isn't going to work on a laminated blade anyway. I check the edge with a file/rockwell chisel, and then have to rely on visual inspection of how the steel is finishing to know whether it's properly hard. This is a laminated white steel blade I made a while back. This particular blade was actually heat treated once before, but I saw clouds in the steel after finishing, so I heat treated it again. For what it's worth, the visual inspection for clouds is done in Japan.



KoPMOMY.jpg
 
I wasn’t sure about buying Rockwell files because I always hear that they aren’t accurate or don’t work, but I could see how they would be helpful with laminated blades. Might be smart for me to pick some up at some point so I have a better reference going forward. And I’ll be sure to inspect for cloudiness as well, I didn’t know much about it until now. Thank you for helping out. And your blade looks beautiful by the way I love how the texture of the bolster matches the small amount of texture on the flats, it’s a very pretty blade.

If you were in my place would you feel comfortable selling these blades? I’m confident they hardened during the HT. But knowing what I do now it’s possible the interrupted quench was too slow, leading them to not hardening enough.
 
I of course can't tell you what to do - and I can't tell from a picture what the state of the steel is. However, I would personally not sell a blade in which I saw cloudiness in the steel. In the case of the above blade, I ground it back to a heat-treatable thickness, did a sub-critical anneal, and then hardened it again. The second time, I was satisfied that the blade was hard and performing properly.

I know you already have a lot of hours in these, so it's really up to you.

If you do decide to re- heat treat, and all you have is a forge, you may want to give it a few heats at a dull red (sub-critical temperature) and allow to cool to black. When it comes time to re-harden it, I wouldn't bother with trying to do a soak (if you have a kiln, then by all means, soak). Just heat evenly to critical and quench.

I am of the Japanese persuasion when it comes to quenching laminated white steel, and would recommend water, with a very thin clay slip on the blade. The clay serves to even out and speed up the quench by creating nucleate boiling points. If you don't have clay, quenching in brine might be best, but I don't have any experience with it – in Japan, they just use plain old water. I would not use warm water, btw. Room temperature or slightly lukewarm is most common. I was taught to quench the blade in water and keep it there until you stop feeling the vibrations through the tongs (usually a few seconds). To be clear, I don't recommend water quenching on most steels, but white steel is really about as shallow-hardening as you can possibly get. Water can still crack a mono-steel blade in white steel, but I've never lost a laminated blade using water.

This is just advice based on my personal experience in making blades and watching makers here in Japan.
 
These blades already have their handles glued on, so I’m not sure I’ll be able to re do the HT at this point. I do have a lot of time and money in them and can’t really just keep them for myself, so I’ll probably price them much lower than I want given the cloudiness. Or more likely give them away to family and friends.

As for future HT I got an Evenheat kiln a few months back and I have been using that since. So going forward I’ll be much more prepared, and HSC’s thread on HT will be a lot of help going forward. These were my first blades using white steel after all so I did expect this to a degree. At least I’m more prepared now.

Thank you very much guys,

Kevin
 
Another quick question. I know for blue steel #2 my data sheets and HSC’s thread say oil or warm water (with water being recommended). Would blue #2 benifit well with parks 50 compared to water? I no longer use canola oil because it is so slow, once I got my even heat I switched to parks 50 (only keeping canola for 80crv2).

Would it be beneficial to me to try both water and oil and see how it compares?

Every chance I get I order a little more of the Hitachi steels. they’re a lot of fun to learn to work, and it’s really helpful that you guys have experience with them. It’s hard to find people that do.

Thanks again,
Kevin
 
I have quenched blue in a fast Japanese oil similar to Parks 50, and it has worked well. Plenty of Japanese smiths also quench laminated blue steel blades in water as well.
 
I guess I would go with parks 50 for blue #2 then, thank you.

Does blue steel need any kind of thermal cycling before HT or is the basic HT enough? I figure with all the tungsten it needs to be properly activated or “dissolved” before hardening. Or because blue #2 is still a relatively low alloy steel like white does it not really require much specific cycling?
 
If you forged it, then it is always wise to thermal cycle the steel. If you are grinding from factory bar stock, just give it a stress relief and the austenitize/quench.

I do all my Hitachi steel in Parks #50.
 
I’m posting this here because it seems unnessisary to make another thread for something ontopic to this thread. I got pretty far in the last few days forging at tanto-ish inspired blade from homogeneous white #2. Yesterday I hardened the blade and when I ground away the decarb after the HT the hamon was too close to the edge. I had this happen to me with some a 1075 blade recently as well.

My HT (using my Evenheat) for the white steel was:

1600° -Hold for 5min-cool overnight

* ground to 120 grit. Applied clay for hamon*

1450° -hold for 10min-quench in parks 50 (in for 4 count, out for 1 count, back in until fully coolled)

400°-2x for 1hr running under warm water between cycles.

I’m planning on increasing my hold temp for the quench from 1450° to 1475°. I’m assuming my even heat is a little off, being low by somewhere between 10°-20°. With a 10min soak time the whole blad ehad to have been at the correct temperature, just slightly too cold. It only takes between 1-2sec (2 kinda pushing it) for me to get the blade from the kiln to the quench.

I will re try th HT this week after work, I’m confident that increasing the hold temp just a little bit will be perfect. There is a lot of detail in this hamon even at a very low grit, but it’s just too close to the edge at the top half of the edge.

Here are some pictures the hamon after the quench: https://imgur.com/a/dEdUp66

I did not take any pics of the clay set up before the quench, but I made sure to keep the clay half the blade width in length away from the edge. This leads me to belive that it’s mostly a hold temperature problem, but I’d still like some input as to what you all think.

What do you guys think?

Thanks
Kevin
 
Kevin, it seems like your primary interest is in the Hamon, you mentioned earlier you focus on them. Myself I've never done a Hamon and have no interest in it, but I know it's quite popular and has it's place.
With that said I can't really offer anything,
However what is the purpose of this? "1600° -Hold for 5min-cool overnight"
I'm thinking this is some stress relief?
1600 seems higher than necessary, I'm at a red orange myself which is probably around 1350

If you would like a Rockwell hardness test done, I'd be happy to do one for you on whatever you want to send me.
 
Kevin, a few things: (Harbeer posted right before I did, so some overlap, apologies)

When you say "1600f, hold 5 minutes, cool overnight"....This is a good normalizing temp for White 2/1095 type steels, and will stress relieve as well. However, what do mean by "cool overnight"? If you mean that you let the blade cool inside the kiln overnight as the kiln itself cooled down, this is not ideal for hyper-eutectoid steels. It places the pro-eutectoid cementite (Carbides) in the grain boundaries. When normalizing or thermal cycling such steel, nothing slower than an air cool should be done. This is a performance concern, and not about hamon/aesthetics. Eutectoid and hypo eutectoid steels like 5160, the overnight slow cool works well, not ideal for hypereutectoid steels.

If stress relieve is what you're after, then 1200-1300f is all the temp you need.
For hamon, I've heard the lower the temp the better the results. White 2 hardening temps are roughly 1450-1475f. Maybe a TAD lower, but not much above 1475f.
I use P50 at 90°F. Only time I would pull it out is if straightening needed to be done in that time period when the steel is still austenite (roughly 900f down to 400f/200f). Otherwise just keep in the oil until ambient.
400F tempers are OK for a tanto knife (provided your as-quenched hardness is where it should be, ~66HRC-68HRC). If the tanto is going to get rough use, you may need to experiment with tempering temps to dial it in where you want it. Kitchen knives in White 2 I would use a lower temp for a harder edge.
My main concern from a performance based standpoint is if you're doing a slow cool on that normalizing heat of 1600f. Not an ideal microstructure, and will be a tad more brittle than if an air cool was done. Plus, after that normalizing heat of 1600f, I would do a thermal cycle (or 2 or 3) just to take care of any "possible" enlarged aus grain due to that higher heat. However, you do have good control of temps I assume with your kiln, so grain enlargement shouldn't be too much of a concern at 1600f.
 
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