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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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Spring temper question.
At what temperature does a music wire spring lose it's temper?
-- Roger Shoaf If you are not part of the solution, you are not dissolved in the solvent. |
#2
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Spring temper question.
Roger Shoaf wrote:
At what temperature does a music wire spring lose it's temper? Some temperature over 150C or so. -- http://inquisitor.i.am/ | | Ian Stirling. ---------------------------+-------------------------+-------------------------- "Looks like his brainwaves crash a little short of the beach..." - Duckman. |
#3
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Spring temper question.
"Roger Shoaf" wrote in message
... At what temperature does a music wire spring lose it's temper? Not to be difficult about it, but a music wire spring has no temper, unless it's been heat treated. Music wire is not heat treated, and it's not normal practice to heat treat it. It gains its hardness and strength from being drawn through wire dies -- through work hardening, in other words. Home made music wire springs are usually wound in that condition, with no heat treating involved. However, maybe what you want know is how much you can heat it before it begins to lose its hardness. In an important sense, it never loses the stiffness of its spring resistance, by the way. The steel has the same stiffness whether it's hard or soft. But softening it lowers its yield strength, so it *does* lose its ability to take a load. You can easily exceed the yield strength of a soft-steel spring, and it won't recover its original length when you take the load off after that. Music wire is plain, high-carbon steel, and so it begins to lose hardness at a low temperatu around 280 deg. F. It progressively loses more hardness as you heat it up to the range of 700 deg. F or so. Ed Huntress |
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Spring temper question.
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#5
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Spring temper question.
Ed
The reason I was asking this question is because I was involved in a discussion about building a coffee roasting drum to be used in a gas BBQ grill and it was suggested that a music wire cotter pin might be used in it's design. When I built my roasting drum I considered using a spring for the door latch but opted not to as I was worried about the reliability in an environment that you are shooting for a 500 F temp. Seems to me you have confirmed this. Thanks. -- Roger Shoaf If you are not part of the solution, you are not dissolved in the solvent. "Ed Huntress" wrote in message news "Roger Shoaf" wrote in message ... At what temperature does a music wire spring lose it's temper? Not to be difficult about it, but a music wire spring has no temper, unless it's been heat treated. Music wire is not heat treated, and it's not normal practice to heat treat it. It gains its hardness and strength from being drawn through wire dies -- through work hardening, in other words. Home made music wire springs are usually wound in that condition, with no heat treating involved. However, maybe what you want know is how much you can heat it before it begins to lose its hardness. In an important sense, it never loses the stiffness of its spring resistance, by the way. The steel has the same stiffness whether it's hard or soft. But softening it lowers its yield strength, so it *does* lose its ability to take a load. You can easily exceed the yield strength of a soft-steel spring, and it won't recover its original length when you take the load off after that. Music wire is plain, high-carbon steel, and so it begins to lose hardness at a low temperatu around 280 deg. F. It progressively loses more hardness as you heat it up to the range of 700 deg. F or so. Ed Huntress |
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Spring temper question.
Ed Huntress wrote:
Because drawing hardens the steel without coarsening the grain, and because some of the tensile strength comes from the grain alignment resulting from successive draws through wire-drawing dies, the properties of the thinner grades can't be duplicated by heat-treating it. The delivered condition, as-is, is as good as it's going to get. I sort of understand how heat-treating hardens steel. So my question is how/why does drawing harden steel? And for that matter how/why does something work harden? Ken |
#7
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Spring temper question.
"Roger Shoaf" wrote in message
... Ed The reason I was asking this question is because I was involved in a discussion about building a coffee roasting drum to be used in a gas BBQ grill and it was suggested that a music wire cotter pin might be used in it's design. When I built my roasting drum I considered using a spring for the door latch but opted not to as I was worried about the reliability in an environment that you are shooting for a 500 F temp. Seems to me you have confirmed this. Yeah, music wire would not be a good choice, unless it doesn't matter if it's quickly softened. If you need real hardness at that temperature (and I'm guessing that you don't really need very much), high-speed steel is the solution. That's a little extreme, but it will hold its full hardness up to around 1,000 deg. F. There aren't many steels that make good high-temperature springs. But the application doesn't sound very demanding, so you'll get it solved without too much trouble. Good luck. Ed Huntress |
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Spring temper question.
"Ken Vale" wrote in message
ogers.com... Ed Huntress wrote: Because drawing hardens the steel without coarsening the grain, and because some of the tensile strength comes from the grain alignment resulting from successive draws through wire-drawing dies, the properties of the thinner grades can't be duplicated by heat-treating it. The delivered condition, as-is, is as good as it's going to get. I sort of understand how heat-treating hardens steel. So my question is how/why does drawing harden steel? And for that matter how/why does something work harden? Ken That's a good question. The answer is that drawing, like most forms of hardening (including much of heat-treating) adds strength by creating strain between the grains. I won't try to elaborate on this here because it's worth a chapter or two of a book. You can find a better explanation in any introductory metallurgy book, even the non-mathematical, practical ones that are used for teaching it as technology, rather than as science. Ed Huntress |
#9
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Spring temper question.
"Ed Huntress" wrote in message t... "Roger Shoaf" wrote in message ... Ed The reason I was asking this question is because I was involved in a discussion about building a coffee roasting drum to be used in a gas BBQ grill and it was suggested that a music wire cotter pin might be used in it's design. When I built my roasting drum I considered using a spring for the door latch but opted not to as I was worried about the reliability in an environment that you are shooting for a 500 F temp. Seems to me you have confirmed this. Yeah, music wire would not be a good choice, unless it doesn't matter if it's quickly softened. If you need real hardness at that temperature (and I'm guessing that you don't really need very much), high-speed steel is the solution. That's a little extreme, but it will hold its full hardness up to around 1,000 deg. F. There aren't many steels that make good high-temperature springs. But the application doesn't sound very demanding, so you'll get it solved without too much trouble. Good luck. Ed Huntress Sometime you just want to ... scream. Just when it was getting good too. Note to self: put the spring on the outside. g wws |
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Spring temper question.
wws wrote:
"Ed Huntress" wrote in message grill and it was suggested that a music wire cotter pin might be used in it's design. Yeah, music wire would not be a good choice, unless it doesn't matter if it's quickly softened. If you need real hardness at that temperature (and I'm guessing that you don't really need very much), high-speed steel is the solution. That's a little extreme, but it will hold its full hardness up to around 1,000 deg. F. Note that a convenient source for the pin might be a broken or dull, small size HSS drill. Ted |
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Spring temper question.
Ed Huntress wrote:
"Ken Vale" wrote in message ogers.com... Ed Huntress wrote: Because drawing hardens the steel without coarsening the grain, and because some of the tensile strength comes from the grain alignment resulting from successive draws through wire-drawing dies, the properties of the thinner grades can't be duplicated by heat-treating it. The delivered condition, as-is, is as good as it's going to get. I sort of understand how heat-treating hardens steel. So my question is how/why does drawing harden steel? And for that matter how/why does something work harden? Ken That's a good question. The answer is that drawing, like most forms of hardening (including much of heat-treating) adds strength by creating strain between the grains. I won't try to elaborate on this here because it's worth a chapter or two of a book. You can find a better explanation in any introductory metallurgy book, even the non-mathematical, practical ones that are used for teaching it as technology, rather than as science. Ed Huntress Can you recommend a couple of titles or authors that might be found at the library? Every time I looked into the subject, I got lost in the science and didn't learn anything practical. Thanks, mike -- Bunch of stuff For Sale and Wanted at the link below. laptops and parts Test Equipment 4in/400Wout ham linear amp. Honda CB-125S 400cc Dirt Bike 2003 miles $550 Police Scanner, Color LCD overhead projector Tek 2465 $800, ham radio, 30pS pulser Tektronix Concept Books, spot welding head... http://www.geocities.com/SiliconValley/Monitor/4710/ |
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Spring temper question.
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#14
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Spring temper question.
"Fdmorrison" wrote in message
... I won't try to elaborate on this here because it's worth a chapter or two of a book. You can find a better explanation in any introductory metallurgy book, even the non-mathematical, practical ones that are used for teaching it as technology, rather than as science. I wish those texts didn't make a distinction between technology and science. So much for books. Well, for textbook purposes, the books written for "technology" programs are either qualitative, in which case they don't use math at all; or they're quantitive, but without the use of calculus or other math that most people don't learn in high school. I prefer the books written for technology programs, rather than the engineering-program versions, in many cases. Anything I'm interested in usually is well covered that way. For example, the courses I had in statics and mechanics were non-calculus courses (I took them years after college), and I got everything I wanted out of them. It was just to satisfy my hobby interest. I wasn't looking for a brain workout with abstraction and rigor. When I learned basic blacksmithing, I was taught that once you changed the iron's(steel's) shape the grain (molecular) structure got stressed, so to relieve this the iron is heated and allowed to cool (aneal), even for mild steel. So in the changing of shape in drawing, there's a similar stress (hardening) added to the steel? Yes, drawing is just one way of work-hardening. It's usually the best way to gain the greatest unidirectional tensile strength in a material. It also gives you the best combination of toughness and hardness in many cases. Keep in mind that the strength and hardness of most metals are directly related. In the case of steel, they actually publish tables that relate Brinell hardness to tensile strength. They assume that the steel is hardened as well as it can be for those tables. In other words, they assume that you haven't overheated the metal and caused a lot of grain growth. If the metal has been cold-worked with a hammer or a press, they assume that you didn't exceed the ultimate compression strength in the process of hammering, which will cause cracks and other faults. If you either heat-treat or work-harden badly, you'll have the local hardness, but not the strength in the whole mass that you should have. -- Ed Huntress (remove "3" from email address for email reply) |
#15
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Spring temper question.
"mike" wrote in message ...
Ed Huntress wrote: "Ken Vale" wrote in message ogers.com... Ed Huntress wrote: Because drawing hardens the steel without coarsening the grain, and because some of the tensile strength comes from the grain alignment resulting from successive draws through wire-drawing dies, the properties of the thinner grades can't be duplicated by heat-treating it. The delivered condition, as-is, is as good as it's going to get. I sort of understand how heat-treating hardens steel. So my question is how/why does drawing harden steel? And for that matter how/why does something work harden? Ken That's a good question. The answer is that drawing, like most forms of hardening (including much of heat-treating) adds strength by creating strain between the grains. I won't try to elaborate on this here because it's worth a chapter or two of a book. You can find a better explanation in any introductory metallurgy book, even the non-mathematical, practical ones that are used for teaching it as technology, rather than as science. Ed Huntress Can you recommend a couple of titles or authors that might be found at the library? Every time I looked into the subject, I got lost in the science and didn't learn anything practical. Thanks, mike -- Bunch of stuff For Sale and Wanted at the link below. laptops and parts Test Equipment 4in/400Wout ham linear amp. Honda CB-125S 400cc Dirt Bike 2003 miles $550 Police Scanner, Color LCD overhead projector Tek 2465 $800, ham radio, 30pS pulser Tektronix Concept Books, spot welding head... http://www.geocities.com/SiliconValley/Monitor/4710/ It's been a while since I've read one, but other people have told me that _Metallurgy Fundamentals_ by Brandt and Warner is a very good technology-level book. You can get a look at the inside on Amazon to see if it's what you're looking for. At $43, you'll want to be sure, but there is a paperback edition, I think. Another one that I refer to often doesn't sound like a metallurgy book, but it does cover steel at a practical level. It's called _Tool Steel Simplified_. It's been in print for many decades but I don't know if it still is. However, it's a book that your local library probably could find at some local or community college and could get for you on an interlibrary loan. That's how I get a lot of expensive books. In the case of _Metallurgy Fundamentals_, you may want to just select the subjects that interest you. In the case of _Tool Steel Simplified_, it's worth going through the whole book. You'll come away with a very good practical understanding of steel. But I'll bet you would from reading the steel sections of _Metallurgy Fundamentals_, too. Good luck. Metallurgy is a lot more interesting than it sounds. g Ed Huntress |
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Spring temper question.
"Tom Quackenbush" wrote in message
... Amazon doesn't list any current printings, but they do offer several used copies. I just ordered one (1960? printing) a couple of days ago, based on Ed's recommendation from a year or two ago. I'm looking forward to reading it. Ed - I think I remember reading a post of yours where you stressed the importance of maintaining the tempering temperature for several hours. I may be mis-remembering & I can't find the post. I'm wondering how this would affect "selective" (I don't know the right word) tempering - as in applying a torch to the spine of a knife blade in order to produce a hardness gradient from the spine to the edge. Does this work at all, or is it counter-productive? Does it work better with "forgiving" type steels (say, O-1 or simple carbon steels)? Given the specific application of scarifying blades for a box scraper, would I be better off wear facing the blades rather than relying on tempering to achieve a hard face and softer, springy back? Also, how much are you charging per answer? g They're still free, but you're left on your own to get confirmation. g Hokay...selective tempering is something that has to be done quickly, and the tradeoff is that you can't gain the benefits of prolonged tempering -- unless you count extended tempering at the *lowest* tempering temperature you're using. For example, you could soften the back of the blade and not quite raise the edge temperature to its final tempering temperature, and then throw it in your kitchen oven at the lowest tempering temperature for an extended time. It's the hardest part of the blade (the cutting edge) that's going to benefit most from this treatment, anyway, so it would work out pretty well, I think. As for the true value of using this selective, or differential tempering, the knife people and blacksmiths will know more about it. It's not a trick that comes from industrial heat-treating. (There is some selective normalizing and annealing done in industry, however; hammer faces are an example, where the center is left hard and a ring around the edge of the face is partially annealed.) I hear that it works and it should be Ok in theory. But here's something that I think you'll encounter in your new copy of TSS: the highest possible "toughness" in high-carbon, low-alloy steels occurs in steel that's been given an extended temper (several hours) at some temperature in the range of 350 - 375 deg. F. Impact strength is not the same thing as flexing strength, however, so beware of different definitions of "toughness" within different metalworking fields. About your box scraper blades and hard facing: it's not something I've ever tried, and I've gotten some pretty poor results trying to hard-face high-carbon steel with Stellite, so I don't do it. Ernie or one of the other weldors probably can tell you better. -- Ed Huntress (remove "3" from email address for email reply) |
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Spring temper question.
"Tom Quackenbush" wrote in message ... I'm wondering how this would affect "selective" (I don't know the right word) tempering - as in applying a torch to the spine of a knife blade in order to produce a hardness gradient from the spine to the edge. Does this work at all, or is it counter-productive? Does it work better with "forgiving" type steels (say, O-1 or simple carbon steels)? Given the specific application of scarifying blades for a box scraper, would I be better off wear facing the blades rather than relying on tempering to achieve a hard face and softer, springy back? Tom Q. Tom, There's a slightly better way of selective tempering and a few little tricks you can use, most important is to do a full temper first to the correct heat for the RC that you want the edge to be. Once this is done, there's a few ways of producing a selective temper, the simplest and not requiring technical know-how is to preheat a reasonable sized piece of steel, big enough to lay the spine on and not so small that it loses it's heat too quickly. Take it out and lay the spine of the edge tool on the hot metal and watch till the straw colour approaches the blade edge (a good way to lose a hamon though :-( ....) . Heat protecting gels just applied to the edge can also help. it's a lot more controllable than the method you described with direct torch heat. The other method is to build a small toaster device that only the back of the blade sits in, only worth doing if you are planning on doing lots of selective tempering. got a link to a knife manufacturer's FAQ that uses selective tempering on their blades, you might find it interesting.: http://www.mdk.idv.tw/mdkfaq.htm#3.11 Simon |
#18
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Spring temper question.
Ok, I'll bite - whats a hamon? Heat treatment line most often associated with japanese swords and clay hardening techniques |
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Spring temper question.
here's a few examples
http://www.bladegallery.com/knives/k...=small&alt=one http://www.knives.com/claytemp.html his method is actually not the most economical or traditional ... the japanese actually scrape away the edge rather than put the pattern on as they apply the clay http://home.earthlink.net/~steinrl/terms/terms.htm |
#20
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Spring temper question.
"Tom Quackenbush" wrote in message
... If I end up going that route I'd probably farm it out to a local welder - I haven't picked up a stick in 20 years. Advice from the r.c.m welders would be very welcome, though. I'd like to understqnd the process even if I don't do the work myself. Here's a blurb from the Navy on wearfacing: http://www.globalsecurity.org/milita.../14250_ch6.pdf Very interesting. I never saw that explanation of sweating with a carburizing flame before. That explains a few things. Maybe I'll try hardfacing again, armed with that information. Thanks, Tom. -- Ed Huntress (remove "3" from email address for email reply) |
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Spring temper question.
On Thu, 02 Oct 2003 06:53:51 -0400, Tom Quackenbush
wrote: Ok, I'll bite - whats a hamon? R, Tom Q. The wavey line one sees on the blade of Japanese edged weapons. Usually as a result of the blade being partially wrapped in clay Gunner Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt. |
#22
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Spring temper question.
"Tom Quackenbush" wrote in message
... On Thu, 02 Oct 2003 12:55:53 GMT, "Ed Huntress" wrote: "Tom Quackenbush" wrote: SNIP Here's a blurb from the Navy on wearfacing: http://www.globalsecurity.org/milita...tc/14250_ch6.p df Very interesting. I never saw that explanation of sweating with a carburizing flame before. That explains a few things. Maybe I'll try hardfacing again, armed with that information. Thanks, Tom. I posted that link by mistake ( I meant to post the link to chapter 7) and hadn't read it until seeing your comment. You're right, that is interesting. I'd be interested in your results if you try it. I'll let you know. I weld out in my unheated garage, and it's pretty cold right now, so it may be a while. g Here's the thing that struck me about the "sweating" business, something I hadn't thought about befo High-carbon steel melts at a slightly lower temperature than low-carbon steel. So, if you carburize the surface a bit with a carburizing flame, you wind up melting a thin layer on the surface of the steel first. If I understand the article correctly, that provides as sort of flux, or a molten interface at least, that helps the hardfacing material to flow and bond. I never raised the temperature of the steel I tried to hardface quite to that temperature. Thus, I never got good results. At least, that's what I gather from the article. -- Ed Huntress (remove "3" from email address for email reply) |
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