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Post by lgarretto on Oct 9, 2014 2:22:07 GMT
I am sorry if this is already somewhere else, I didn't really see it..
So I was just wondering: why exactly is stainless steel considered so terrible for swords? I have heard that it's too brittle, that it doesn't hold an edge well, even that it's difficult to work. And as a machinist by trade, I will attest to the last one. It is much harder than carbon steel and harder to work and cut. But it would seem like that is why you would want it. For example, I own 4 swords, all the same one (because they were 10 dollars at a med fair) and I have taken all 4 apart and remade them. The hilts were horrific. But the blades are very good. They vary in length, but the longest is about a 30in blade about 2 inches wide at hilt. And (granted they don't look so wonderful due to my skills in the shop) they perform wonderfully. They have very little flex to them, and they hold an edge very well. I have also never snapped or bent one. In fact, the stainless blades hold up as well or better than all my other swords. (which for reference include 2 hanwei's, a tinker pearce, a strongblade, 2 darks word Armourys, and a Chenness. Among others) I am fairly hard on all my swords. I don't hold back and I don't go easy. I just do as I feel like doing with them. This has gotten me a chipped tip on my Cheness, a set tip an my hanwei side sword, a couple of chips out of my darks word Armoury, and numerous nicks. But the stainless just seems to hold an edge longer and fare better.
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Post by lgarretto on Oct 9, 2014 2:23:39 GMT
By the way, I would like to mention that I am not posting this to try and start an argument or put anyone down in any way. I am asking out of sincerity due to my experience both with sword and with working metal
Also, thank you
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Post by LG Martial Arts on Oct 9, 2014 3:00:58 GMT
Here's a couple of vids that should explain why SS swords aren't good for swinging around, cutting with, etc.
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Post by Lonely Wolf Forge on Oct 9, 2014 3:23:01 GMT
i owned a stainless steel sword when i was a kid and that thing took horrible horrible punishment. chopping at trees ext. but it was only a 21 inch blade and was around 1/4" thick. i never did break it until like an idiot i heated it on bonfire and plunged it into a bucket of ice water....kids will be kids? right?
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Post by Timo Nieminen on Oct 9, 2014 3:32:13 GMT
"Much harder" depends on the alloy and the heat treatment. 440A can be hardened to about HRC56-58, 440C to about HRC60. Carbon steels with about the same carbon content will reach about the same hardnesses.
440A is OK for swords. With good heat treatment, you'll end up with the hardness of 1060 and the toughness of 1095 (i.e., the brittleness of 1095). But with good corrosion resistance. Carbon steels will generally give a better compromise between hardness and toughness.
Other stainless alloys can be OK as well, with good heat treatment. The problem is with decorative swords which can have very poor heat treatment, or with swords made with knife steels and heat treated the same as knives. For example, a sword made with 440C and heat treated as a knife would be can be too brittle.
But done properly, the right stainless alloy works. Mechanically inferior to carbon steels, but if you value corrosion resistance, it can be a good choice.
How far the blade flexes under a given load depends on the blade thickness and geometry, not the steel. Whether it stays bent or breaks or returns to true depends on the alloy and the heat treatment.
Some stainless alloys will give better edge retention at the same hardness compared to carbon steels due to better wear resistance.
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TomK
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Post by TomK on Oct 9, 2014 3:46:36 GMT
Ok, there's actually a lot I want to say in this thread, but I don't have time now since I am at work. Posting this will put this thread in my ego search list so I will remember to post when I get home and it won't be lost.
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Post by lgarretto on Oct 9, 2014 3:47:52 GMT
That makes a lot of sense and really helps Timo. I was never talking about a cheap or poorly manufactured stainless sword, just why stainless is inferior to carbon in the making of a sword. However there is one thing I don't understand with what you said. My darksword Armoury sword measures 2 and one quarter wide and about point 22 thick (with calipers) and this stainless blade measures point 187 thick and about an inch and 3/4 wide. Gripping the sword the same distance apart, the stainless blade is considerably harder to flex. I know the stainless is 440c,because I made it. I'm not sure what the darksword is
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Post by aussie-rabbit on Oct 9, 2014 3:58:46 GMT
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Post by Timo Nieminen on Oct 9, 2014 4:20:09 GMT
Young's modulus for steels is about 200GPa (or 30x10^6 psi), from mild steel through to high carbon steels like 1095, and various alloy steels (such as most stainless steels). Almost independent of the heat treatment, too. You need to go to cast irons before you see a big change.
So, the Darksword blade should be about twice as stiff, if the blades have the same geometry (stiffness is cubic in thickness, and linear in width). However, it does depend on the geometry - if your 0.187" thick blade is 0.187" thick for most of the width, and the Darksword is 0.22" thick only at the thickest point, and thinner for most of the width, then the 0.187" blade can be stiffer.
If you're interested, you could do a more accurate measurement than "feels stiffer". Clamp each blade, hang a weight at the same distance from the clamp, and measure the deflection. Or put the blade between two supports, and hang a weight from the middle.
If the 0.187" blade has similar geometry to the 0.22" blade but is stiffer, the only thing that I can think of as a possible cause is residual stress (from forging/heat treating). Which might not be a good thing to have in a blade.
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TomK
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Post by TomK on Oct 9, 2014 8:04:01 GMT
ok where to start . . . I guess I'll start out by front-loading you all with the fact that I am sitting squarely in the "no stainless steel for swords" camp. why? this is a good question. I have been learning a lot lately about steel metallurgy but I have not been studying stainless in particular. the information I have on why not stainless currently comes from the teaching I have received from sword makers. specifically, Gus Trim and Tinker. I have learned a lot more from Gus than Tinker as I speak with Gus regularly and have done so for years. I have only spent a limited amount of time with Tinker but learned great stuff every time. Also as Tinker and Gus are very good friends they tend to share knowledge and I have gotten a lot of information from Tinker second hand through Gus(who of course, had great info to add himself). ok that is called full disclosure, not all the info I am going to present here is stuff I have found in scientific works. I want you to understand though, that I feel Gus and Tinker are very solid sources and I choose to believe them explicitly until I have strong evidence to the contrary. so now, the reason stainless steel is no good for swords (as I have been taught): the primary difference between stainless steel and carbon steel is the chromium content. Carbon steel has basically none while stainless steel has quite a bit, as in 16-18% for the 440 series. chromium is the key. it is what makes stainless hard to abrade or wear down with belts or cutting tools etc. it also does good things to edge retention. so why don't we like it? it all happens in the crystalline micro-structure of steel. hardened steel is hard because when it gets cooled carbon gets trapped between the iron atoms and stretches them out away from each other making them pull harder to try to stay together. this structure is called Martensite and when it is fresh (or untempered) and the carbon content is above .30% it becomes very brittle. most of us know that it needs to be tempered to be useable. tempered Martensite is extremely tough. in fact the more it is tempered (lower hardness) the tougher it gets. this has nothing to do with the grade of the steel (yet). in steel that is heat treated well the size of the grain structure is quite small. this is desirable as it too increases toughness and durability in steel. and now we get to the fly in the ointment. compared to steel's grain size, chromium carbides are pretty darn big. and they get caught in the structure of the steel too. as long as they stay put, everything is happy and the steel is really good stuff. the problem comes when the steel starts to flex in large waves. because the chromium is so much bigger than the steel and carbon a large wave passing through the steel can create stress points around the chromium carbides. if enough stress is induced the carbides can move through the steel lattice. this can disrupt the nice tight even structure of the hardened steel softening it, or it can straight up over-stress it and cause cracks and splits. it takes a fairly significant wave to cause this however, and blades that are short (I've never been able to get a clear answer on exactly how short) simply do not allow large enough waves of motion to develop to cause problems. thus Stainless is ok (in fact it is great) for knives but not so good for swords. now does this mean 440C stainless that has been worked by a talented smith/craftsman and heat treated with care and precision still is no good for a sword? I would say yes, though it is not as bad as the forum hype would have you believe. it would depend on the type of sword, the stiffness, and the heat treat and of course all those other little important things that go into construction. if it is done well, stainless can probably be ok, but it will still be inferior to carbon in the long run. this may not show up right away and a stainless sword could possibly serve as a decent intro sword. but I wouldn't trust it. you never know when those chromium devils are gonna start causing trouble. now in that long discussion I mentioned that Martensite, when tempered, is very tough. I am sick to death of the myth that 1095 steel is not tough, this is simply not true. it all depends on how it was heat treated. as quenched, 1095 tends to be about 65-67-ish HRC which is dang hard. but the more you temper it the tougher it gets. 1095 tempered to 53 HRC is no less tough than 1060 tempered to 53 HRC. in fact, it can be argued that 1095 at 53 is actually TOUGHER than 1060 at 53 because the 1095 has had more stress relieved from it. I'm not sure on that, but I do know it is no less tough for sure and it would be more tough than a 10 series steel that can only reach 53HRC maximum because the untempered Martensite would still be brittle. the videos above do NOT show why stainless steel is bad for swords, they show that bad craftsmanship is bad for swords. most of us already know this. so now we come to ANOTHER reason stainless steel is bad for swords and this has nothing to do with metallurgy. stainless steel is used by sword makers who are not making swords. I'm sorry to say it this way, but chances are very close to 100% that anyone making a sword out of stainless steel does not know how to make a sword properly and it is going to be unsafe due to crappy craftsmanship more than poor materials. stainless steel is fussy about heat treat and the processes you need to put it through to do it right are precise, complex, and therefor expensive. 10xx series steels are extremely easy to heat treat to a decent level of quality. heck you can do it in your back yard with a gas torch and a bucket of hot canola oil. so, anyone selling a stainless steel sword for less than $100 (heck probably for less than $250+ even if it is from China) is selling you a piece of steel that is not heat treated. ultimately, this may be good for the stainless blade. the chromium can make a stainless blade hold a half way decent edge even un-heat-treated. those cheap knives you get a K-mart, you know the $20 dollar blue-light specials, they are almost for sure not heat treated. also with people selling stainless swords, you never know what grade they are using. it could be 303 or something entirely unhardenable. so to all you who protest about how you have this great stainless steel sword that has proven tough and safe I say bull-sh . . . well sort of. fact is many swords in medieval days were basically unhardened. not the good ones I'd assume, but many all the same. especially later on when you started finding munition grade kits on the field. anyway your stainless sword could be entirely unhardened and as long as the hilt and tang are healthy there is probably little chance of disaster. it. is. not. a. good. sword. stopit! finally yes, there are some very exotic stainless steels on the market that may in fact make a decent sword blade. they are very tricky to work with, a real bugger to heat treat, and the only thing they can do better than carbon steel is not rust so easily. in the end high carbon is still the way to go even though there are some very nice stainlesses to choose from. unless the craftsman has a name like Kevin Cashen, or Vince Evans, or Jesus Hernandez, or Don Fogg (you get the idea) I would run screaming from any stainless sword on the market because if it is made of stainless and NOT by a smith of the caliber of the above mentioned gentlemen, it is not made properly.
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TomK
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Post by TomK on Oct 9, 2014 8:26:15 GMT
also I'd like to say that I agree with Timo in pretty much all he says above. especially about the flex testing. geometry is super important.
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Post by Dean on Oct 9, 2014 8:51:25 GMT
It is always a trade off. www.metalformingmagazine.com/ass ... n/Fig1.jpg Depends which "stainless steel" you are talking about. Practical reasons are probably the real reason why they are not used. Material Cost Skill and machinery required Heat treatment On going maintainence. (Ie some take a lot more skill to resharpen) As general rule, as the wear resistance increases (desirable), the strain/stress factor increases (undesirable) This make give you some idea, but it is "relative" comparison and is short on specifics. www.midwayusa.com/technicalnotes ... _chart.htm
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Post by lgarretto on Oct 9, 2014 14:53:16 GMT
That actually explains exactly what I was asking Tom. Thank you. A poorly made sword is a poorly made sword. And whatever it is made of, it is the craftsmanship that comes down to how well the sword as a whole stands up. In that respect, my kid cousin has a plastic dollar sword that has been around for YEARS, and I'd say it has held up better than some cheap wall hangers I've seen haha. Either way, thank you all for your explanations. I personally happen to still like a couple of my stainless swords as well as I do my high carbon ones, but that isn't to say I didn't just get lucky with a good temper in the stainless probably did just get lucky. Besides, other than the temper I made them myself, I trust my own handiwork personally. Either way I now understand why I shouldn't trust stainless. Thanks
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Post by Robert in California on Oct 9, 2014 16:00:35 GMT
great info! Thanks! RinC
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Post by LG Martial Arts on Oct 9, 2014 16:05:41 GMT
Great info as always Tom. The vids I posted were just for reference since I don't have personal experience forging anything (yet!)
LG
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