XC130 Steel discussion

This is a steel that I sometimes use for razors on which I want to create a hamon. @RezDog wanted to open a discussion about it for some questions, so let's have them

Ok. So the carbon content is quite high, well at least it seems that way. Lets see if I have some of this correct. Mild steel has a very low carbon content and because of that it does not harden. So is XC130 capable of being much harder than say 1095?
is there an advantage in razors to having that much higher of a carbon content?
Does it make it more challenging to forge?

Bruno - is that a readily-available steel for you, or something you need to special order? Some quick googling sure didn't turn up much on this side of the Atlantic.

I'm a total noob when it comes to hamons, but as it's something I'd like to play around with, I'm also curious how XC130 would compare to W and O series steels, as well as the 10 series.

Lots of good questions.

Yes. Carbon content is high. I guess XC130 would be capable of being harder than 1095, but there is no point because imo a razor that is harder than 61 or 62 HRc at most, is defective. Above 62 you get microchipping, and brittleness that makes it difficult to hone.

Is there a real advantage? No, not really. At least not in terms of shaving. Altough... we could argue about that, I guess. You see I quench these at the same temperatures as I would quench 1086. That means that part of the carbon goes into austenite, and part goes into cementite. So you get the martensite edge, riddled with tiny cementite carbides. And they may or may not improve edge retention while shaving.

It's not challenging to forge. I find it easier to forge than O2 or O1. In general the carbon doesn't have as much influence on forging as the other alloying elements. Vanadium and Managese and other will make forging much more labor intensive than just the carbon. Those supersteels I have waiting would be MUCH harder. The Vanadis 8 for example... That has 8% Vanadium and 3.6% Molybdenum. I'd like to see someone forge that by hand from a piece of thick bar

The steel is readily available at times from a specific supplier, but I haven't been able to track down who makes this. I can only by it in 6mm thick rectangular bar., and I would like to have it in thicker bar. Most knifemakers use flat, but since I am doing integral bolsters these days, I would love to start with 3/4" thick stock.

The main reason I like it is that the extra carbon means that if I do the heat treatment with the hamon correct, there is much more carbon doing wild things around the hamon, which should make for a lot of extra visual activity. But so far that doesn't always work because I am still figuring things out.

So the typical pattern welded steel is 1095 and 15n20. I have always just presumed that these two steels are used together because the dramatic difference in the etched colour combined with that the heat treat and temper is the same. So could XC130 also be combined with another steel to make pattern welded steel?

Actually, 1095 wouldn't be too dissimilar but it really doesn't matter because after folding a couple of times folding, the carbon content will have homogenized.

But I use O2 instead of 1095. It has more or less the same amount of carbon, but a lot of manganese. The manganese makes it etch darker. As for the 'bright' layers, they should be rich in nickel. L6 is a common one in the US, and a favorite of Howard. 15N20 is similar, but has more nickel, and is therefore brighter after etching.

So a pattern welded billet with O2 and L6 would make for a nice sharp contrast?
more contrast than 1095 and 15N20?

O2 and 15n20 is better because the 15n20 has abput double the nickel of l6

There is good data from metallurgical studies in post-war Japan. Their baseline tradition dictates that the best hamon are from blades with about 0.60-0.71% (9 ryu out of 10 at 0.60-0.62%, 1 ryu at 0.71% consistently) carbon. Tamahagane is mixed with lesser steels in the orishigane and over the forging process the eventual carbon content settles in this sweet spot.

This is not to say you cannot make a hamon above that range. The hamon is less dramatic and the blades carry a higher risk of the dreaded ping.

Mike Blue said:

There is good data from metallurgical studies in post-war Japan. Their baseline tradition dictates that the best hamon are from blades with about 0.60-0.71% (9 ryu out of 10 at 0.60-0.62%, 1 ryu at 0.71% consistently) carbon. Tamahagane is mixed with lesser steels in the orishigane and over the forging process the eventual carbon content settles in this sweet spot.

This is not to say you cannot make a hamon above that range. The hamon is less dramatic and the blades carry a higher risk of the dreaded ping.

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That is interesting. It runs counter to the limited testing that I have done. But I was only able to compare a handful of types of steel, and there was quite a lot of variance in the alloying elements that were present. So it is likely that my results were more caused by things other than carbon.

I have no problem in admitting that I was wrong.

My tempering comment is that the Japanese are bound by a strict tradition as well. I remember rather direct feedback that a carbon steel of 0.86% was "too much carbon" with a audible disgust emphasis. That did not hinder any interest in how the blades performed or what the Americans were doing outside the limits of their playground. They are all avid metallurgists.

[QUOTE="Bruno, post: 8864, member:] The steel is readily available at times from a specific supplier, but I haven't been able to track down who makes this. I can only by it in 6mm thick rectangular bar., and I would like to have it in thicker bar. Most knifemakers use flat, but since I am doing integral bolsters these days, I would love to start with 3/4" thick stock.
[/QUOTE]

What about forge welding extra material at the bolster? I know, not as sexy as using round bar or square but the affect would be there.

More thoughts. I know you have O-2 available. But more manganese runs contrary to the desire for a hamon in the first place. Hamon development is best in low hardenability steels. This means the least amount of manganese you can get. Manganese is encouraged in alloys to make them through harden not differentially harden. Even with clay getting a manganese steel to show a hamon is not easy.

Jfk742 said:

What about forge welding extra material at the bolster? I know, not as sexy as using round bar or square but the affect would be there.

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That is one way to deal with it. The downside is that you're likely to see a forgewelding line after etching. That may or may not be visible in the end result. I've also just stacked a couple of pieces and forge welded them together to make a 3/4" thick bar. That works too.

More carbon doesn't always mean better as quenched hardness. You'll get a peak in hardness at around 0.92% if I remember well. From there, what the extra carbon does, is to form cementite(iron carbides). Those are slightly harder than the as quenched steel(around 70hrc) and will improve the steel's abrasion resistance. Cementite usually is much smaller than the other carbides found in alloy steels and will not impair toughness as much.

I also agree with Mike about hamon activity. The "shallowest" hardening steels will produce the best hamon activity. The best hamon steel I've worked with so far is Aldo's W2. It's manganese content is as low as 0.20%. I believe the average tamahagane steel can have manganese as low as 0.1%, or even less.

The picture below is Aldo's W2 and the short video is Veostalpine 26c3. 26c3 has a slightly higher manganese content at around 0.30% and a pinch of chrome. It's still quite shallow hardening.

I love how subtle it is. Is that just through polishing or did you have to etch it as well?

Jfk742 said:

I love how subtle it is. Is that just through polishing or did you have to etch it as well?

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Mostly polishing. Just one very short dip in 1:7 diluted ferric.