Increasing strength of steel through rolling

Nice machines, and a good lesson in rolling mill design. I see what you're getting at. I certainly appriciate the links.
I had assumed that a larger working roller would increase torque requirements. I didn't even consider backup rolls.
That's not as much as I had hoped. Mind you, I also don't need hundreds of feet per minute feed (at least not yet). The real difficulty in this situation is that I can't really prototype rolling economically. If I really want to know, I'd have to pull the trigger and aquire a rolling mill (one way or the other). Expensive experiement.
Fair warning.
Regards,
Robin
Reply to
robinstoddart
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I remembered reading that when I was considering research for this application, and I read it again during that research on RCM :)
It's hard to fathom this idea. I'm not saying I don't believe it, it's just not intuitive. For this reason, I might as well just get some material and cut out a blank (Dremel and a hand drill) and start testing. Propane torch to harden the teeth.
Regards,
Robin
Reply to
robinstoddart
Modern Marvels, episode 487 - "World's Sharpest". I can't find any clips or downloads for that episode unfortunately. Now you've got me drooling :)
Regards,
Robin
Reply to
robinstoddart
1095 seems to be a fairly common alloy. Indeed, McMaster-Carr sells it in .025 thickness at C44-C51 hardness for not too much bucks. Certainly a possibility.
Yeah. Trying to keep the cost of each part low.
I looked into that type of work. Bimetal blades are electron-beam welded or laser welded. Both beyond my means at this point, although that doesn't mean I couldn't get someone else to make the coil for me. Shouldn't be too expensive if I'm willing to invest in a large (!) order.
Thanks for your thoughts. Helpful suggestions.
Regards,
Robin
Reply to
robinstoddart
Sci. Channel
"How Its Made"
"Scalpels, Oil Paints, British Police Helmets & Ice Axels"
Reply to
brewertr
Whether it was on that program or not, one "documentary" showed double-edged razor blades being made from continuous rolls of stock.
The blades were only seperated when it was time for encapsulation/packaging.
Everything else was done to them while they were still attached to each other.
Reply to
RAM³
I know it isn't intuitive, that's why I mentioned it. An easy demo is to clamp two identical pieces of hardened steel in a vise with enough sticking out that you can easily bend them, then anneal one. I posted a demo recently using sheetrock screws, or you could try cheap (carbon steel) hacksaw blades. Heat one red to anneal it, let it cool, then see how they both bend as you slowly increase finger pressure.
In technical terms hardness raises the yield point but doesn't change the coefficient of elasticity. I think hardness restricts microscopic rearrangement of crystal boundaries or slippage planes.
You may have problems experimenting with hardening and tempering unless you have some way to measure the properties of your samples. The standard lab tests are hardness, usually measured as resistance to penetration, and elongation under load. The important number is the Yield Point or Elastic Limit, the force/area where the sample stretches permanently. There really aren't any simple, cheap, accurate ways to make these measurements at home. Common practice is to temper to a color appropriate to the tool's application. What are you cutting?
Jim Wilkins
Reply to
Jim Wilkins
I've done manual induction hardening using a hand-held unit (with a massive umbilical cord to a large machine) for hardening trim edges and form/draw rads on large stamping dies.
The problem in induction is the cost. The machines are bloody expensive. I'd very certainly investigate going with induction once I think I have something worth selling, but right now it's not worth the money/hassle.
Regards,
Robin
Reply to
robinstoddart
I'll take your word for it :)
I must say, however, that in my case the part runs significant risk of being forced beyond its elastic limit due to its thickness. In this case, strength does have a bearing on rigidity, so I'm not completely convinced that hardness is trivial. This will be a tool that people will abuse, and increasing strength/hardness will have an effect on the tool's usefulness.
I'm actually a tool and die maker by trade, so I have a certain amout of experience with heat treat and dealing with hardened versus soft materials.
I'm at a very early stage, so I'm not too concerned with the exact numbers involved. I'd get a hardness tester of some description, likely before I start building the tooling.
Wood, and at not very high surface speeds.
Thanks for the thoughts. It's very useful to go through the thought processes and try to be cirtical of all these issues.
Regards,
Robin
Reply to
robinstoddart
Sawmill bandsaw blade stock might be practical, then. Perhaps you could find some free dull blades to experiment with. Unlike some metal- cutting blades the set doesn't extend to the bottom of the gullet so if you remove the teeth you have flat material. The set on metal cutting blades is a nuisance to remove because the thin steel doesn't stick to the magnetic chuck of a surface grinder very well. In my limited experience these blades are tempered enough to yield a little rather than shattering dangerously when overstressed.
Jim Wilkins
Reply to
Jim Wilkins
Steve:
I've always liked Robin, and thought an answer to his question might be helpful. Wasn't that what this newsgroup used to be all about?
Heh, it seems his quantities are too high for my suggestions to be of much use. I thought the razor blade manufacturing idea was a good one.
Reply to
BottleBob
I like Robin also. Yes, helping was and should be the reason for the group. Things have sunk pretty low as of late, but things also have a way of coming full circle.
We can hope.
As was the band saw blade stock and a few of the others.
Best, Steve
Reply to
Garlicdude
I'll take your word for it :)
I must say, however, that in my case the part runs significant risk of being forced beyond its elastic limit due to its thickness. In this case, strength does have a bearing on rigidity, so I'm not completely convinced that hardness is trivial. This will be a tool that people will abuse, and increasing strength/hardness will have an effect on the tool's usefulness.
I'm actually a tool and die maker by trade, so I have a certain amout of experience with heat treat and dealing with hardened versus soft materials.
I'm at a very early stage, so I'm not too concerned with the exact numbers involved. I'd get a hardness tester of some description, likely before I start building the tooling.
Wood, and at not very high surface speeds.
Thanks for the thoughts. It's very useful to go through the thought processes and try to be cirtical of all these issues.
Regards,
Robin
Robin, The fact the modulus of elasticity, which determines stiffness is virtually the same for all grades of steel, and also for all grades of aluminum, brought me one of my greatest teaching moments. I had a young engineer working with me and we had an aluminum clamp frame in a packaging machine that was deflecting too much. He suggested using high strength aluminum and I agreed that he should check it out. The next day he came in and said "You knew didn't you! Why didn't you just tell me?" I said that it was engineering 101 and he apparently didn't learn it in school, but he'd remember it for the rest of his life now!
Sadly, I was right again. About 2 years later he committed suicide. No, he wasn't working with me at the time!
Gary H. Lucas
Reply to
Gary H. Lucas
Gary:
Nothing like a story with a happy ending to cheer up the troops.
Reply to
BottleBob

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