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Post by miraculix101 on Feb 11, 2024 1:04:56 GMT
Hello all, for my next purchase of a custom(length, width, sori, Motohaba ,sakihaba ,Motogasane and sakigasane) katana blade i am indifferent of the steel i should use. Normally i would go with a 9260 spring steel, guess you cant go wrong there.
But i would like to know of you, who have way more knowledge in this area, than me if and what the bend tolerance in degree the different of steel types are: I assume, that the steels are heat treated correctly.
9260 TH up to 90° degree 9260 DH =?
1095 TH =?
1095 DH =?
1075 TH =?
1075 DH =?
1060 TH =?
1060 DH (no one i know of does 1060 DH, but i can be wrong) 5160 TH =? 5160 DH =? (dont know if 5160 somebody makes DH) T10 TH =? (if someone makes them, i dont know)
T10 DH =?
Would be nice to have an according list, which would be helpful for everyone who is standing before a decision like i am at the moment.
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Post by AndiTheBarvarian on Feb 11, 2024 2:50:30 GMT
I'd like to know this myself but I fear it's hard to find exactly this stats for sword steels, esp. with different heat treatment TH vs. DH. What you want to know is the "yield strength" of the material, how much force can be applied before elastic deformation turns into plastic deformation. Best I could find so far is this: www.solidmechs.com/2019/09/steel-alloys.htmlAt least the charts give an idea how carbon content and heat treatment effect and you can compare 1050 to 6150 to see alloy effects. Unfortunately so many other factors are important for a whole blade. Looking at those metallurgic stats is going down the rabbit hole. It gets so complicated that it's nothing but confusing. That's why nobody found the perfect sword steel yet, or heat treatment or anything else. In the end I have some rules of thumb: Find a smith or company with a trustworthy heat treatment Take the steel they use. Semprini happens I think it's better to have a mediocre commonly used "forgiving" steel like 5160, 1060, that isn't affected much by little mistakes, than a theoretically super stats supersteel, that only works with the perfect treatment.
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Post by larason2 on Feb 11, 2024 5:03:26 GMT
Differentially hardened blades don't really have yield strength like through hardened blades do. The edge will bend and come back just like the through hardened blade, but the spine will always set, no matter what, giving you a crooked blade. So it's best not to test them this way. If you get a set in your DH blade, you can always bend it straight though, but you risk cracking it, particularly if you don't have the right tools or experience! That being said, with cutting it usually doesn't matter much. Most of my longquan blades have come crooked, and I've straightened them out with my Elm sword benders
For through hardened though, whether it's tempered as usual or spring tempered makes a difference in yield strength (but not much difference in use). That kind of data is hard to find though, it's not clear how exacting the tempering is from many manufacturers. Again, in use it probably doesn't matter
In theory, a spring made from 1095 will have more yield strength than one made from 1060, assuming proper spring temper, but in practice, I don't think you'll be able to discern a difference, and the 1095 will be more likely to chip.
So, the bottom line is if your sword is going to be getting abusive cuts, get a TH, if not, yield strength probably doesn't matter. No matter how high the yield strength is, a sword can still break, and most swords don't really need to bend.
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Post by crazyjons on Feb 11, 2024 5:18:21 GMT
So I have some Ronin katana dojo pro 1060 through hardened blades, and you can bend all of them quite severely and they will snap back to straight like I think almost 30° is the most I've tried. I also have a Ronin katana Hanzo steel black coated blade that is supposedly 1060 differentially hardened. It has a hamon. It bent and took a set cutting wet phone books and I had to straighten it. As was said previously I would not try a flex test with a differentially hardened blade. I have flexed both 1075 and 1080 through hardened blades a pretty significant amount and they snapped back straight. Same with a couple Cold steel 1055 swords, I guess a couple years into this hobby I am quite a bit less aggressive in flex testing swords because you just don't know how much is too much until you get there.
Jon
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Post by AndiTheBarvarian on Feb 11, 2024 6:01:23 GMT
Hardness, toughness, brittleness, yield strength, tensile strength, ductility. All somehow connected and depending on each other, directly or reverse. Madness!
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Post by mrstabby on Feb 11, 2024 12:10:20 GMT
The problem is that everything is connected. You can make a 10-series blade that returns to true from a 90° bend, but it likely won't hold an edge as well as the 9260. Or you can make a 5160 that breaks. around 11min, 1095 is 54HRC, 5160 is 52HRC, last 5160 is 57HRC
You would need to set at least one variable, like hardness or edge retention, to a specific value to compare such things, and that might not work either (looking at the video, the 5160 would need to be a lot softer to get the same outcome as the 1095 it seems). Knifesteelnerds is a good ressource. The toughness section is around a fifth down.
You can guesstimate what you need since many of the connections are linear (like lowering hardness to get more toughness, the toughness seems to rise linearly for most). The values are where the steel breaks (ultimate strength), I can't say what relation breaking strength has to the limit of it's plastic deformation unfortunately.
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Post by miraculix101 on Feb 14, 2024 15:12:08 GMT
Ok guys, thank you very much for your answers. A shame that there isnt more knowledge around, which could have completed my list above.
That 9260 can bend 90° degree i have seen on some videos, so that is a proof of the steel.
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Post by AndiTheBarvarian on Feb 14, 2024 15:28:28 GMT
Less problems with bending a thin wire this way than a thick blade. I've heard of epees bending 360° and spring back. Wouldn't try it with a katana, even a TH one. So many variables.
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