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Post by darkhorse on Sept 3, 2024 18:42:10 GMT
Does through hardened mean that a blade has the same HRC consistently throughout? I know there is clay tempering, which produces a hamon, and I also see some swords described as having different HRC on the spine and the edge. Would a sword with differing HRC on the spine and edge but no hamon be considered "differentially tempered" or "through hardened"?
The example I'm thinking of is an ultra-budget, somewhat non-traditional katana with a spring steel blade and no hamon. I have heard that the HRC is supposedly around 45 at the spine and maybe around 55 at the edge.
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Post by mrstabby on Sept 3, 2024 19:23:43 GMT
There likely will be some sort of difference, like a few HRC, along the blade and on the inside on something through hardened. Some steels are more shallow hardening and only harden a few millimeters deep like 1095, more modern steels are made to be deep hardening and therefore won't have as much of a hardness difference on thicker blades and differential hardening needs some special doing.
If there is a difference between spine and edge (like 40-55 you mentioned) it counts as diferentially hardened even if it doioes not show any hardening lines. Many modern spring steels do not show hamon well (because of composition and hardening characteristics).
52-55HRC is good for through hardened blades, a 55HRC edge on a differentially hardened sword sounds a bit soft IMHO, I have read it's normally 30-40HRC on the spine and 60+HRC on the edge (depending on the steel). 55 is OK for budget.
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Post by darkhorse on Sept 3, 2024 19:42:08 GMT
There likely will be some sort of difference, like a few HRC, along the blade and on the inside on something through hardened. Some steels are more shallow hardening and only harden a few millimeters deep like 1095, more modern steels are made to be deep hardening and therefore won't have as much of a hardness difference on thicker blades and differential hardening needs some special doing. If there is a difference between spine and edge (like 40-55 you mentioned) it counts as diferentially hardened even if it doioes not show any hardening lines. Many modern spring steels do not show hamon well (because of composition and hardening characteristics). 52-55HRC is good for through hardened blades, a 55HRC edge on a differentially hardened sword sounds a bit soft IMHO, I have read it's normally 30-40HRC on the spine and 60+HRC on the edge (depending on the steel). 55 is OK for budget. Thanks. That answers my question pretty well. I'll probably be reviewing a cheap "beater" I got for under $65. It will probably be here tomorrow. It's something fun to check out while I select and wait for a really nice sword. |
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Post by mrstabby on Sept 3, 2024 19:49:22 GMT
Be a bit careful though, differentially hardened swords tend to bend (relatively) easily from botched cuts or when it gets hits on the side, and the lower hardness the spine the easier it will bend.
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Post by darkhorse on Sept 3, 2024 20:08:32 GMT
Be a bit careful though, differentially hardened swords tend to bend (relatively) easily from botched cuts or when it gets hits on the side, and the lower hardness the spine the easier it will bend. Yeah, I've heard. A lot of my information on the sword is second-hand information not provided by the manufacturer and/or sellers. There is a picture, probably from the manufacturer or a seller, of a flex test. I'm going to continue researching it. They don't specify the type of steel the blade is made from, simply calling it "spring steel". I do know that the tang is really beefy, having seen the handle...I guess you could call it deconstructed rather than disassembled. There's some kind of glued on foam or something under the wax cord rather than wood. Not traditional, but functional enough. I have seen footage of it cutting, including tatami. I have seen customer reviews saying that the quality of the blade is comparable to or better than some $100-$200 and I think maybe even pricier budget katana swords. I'd like to believe that those reviews are by one or more actual satisfied customers and not shenanigans, and they could well be. At that price, there's not much to lose. |
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Post by crazyjons on Sept 5, 2024 14:11:08 GMT
The swords that I have purchased in the under $100 category... Aren't even spring steel. so they will bend, doesn't matter how thick the Tang is.
Jon
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Post by mrstabby on Sept 5, 2024 15:44:25 GMT
Spring steel and spring temper aren't the same thing though. Most steels that are called "spring steel" have ingredients that make achieving a good spring temper easier, but if it got differentially hardened or an interrupted quench was done (basically pulling out before it has achieved max hardness so you don't have to temper) it's not gonna behave like a spring. I have heard a lot cheap manufacturers use interrupted quenching. EDIT: Besides modern spring steels (5160, 9260, 1066, 60Si2MnA etc) the 10-serie steels also can make springs even though they were not specificalllly made for it. Sometimes these are also called spring steel because they can make springs but if the temper is off it's not gonna be springy either way. Just saying because I have seen spring steel being advertised for differentially hardened blades.
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