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4130 Chromoly vs. Reynolds 853 Steel
Can any of you explain the diffrence between the various steels used
for bicycles and their comparitive advantages? Example: A Lemond Zurich (DF) boasts a Reynolds 853 sticker on the frame. It seems as though all of the steel recumbents are 4130 chromoly. Thanks in advance. |
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#2
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4130 Chromoly vs. Reynolds 853 Steel
Bobinator wrote:
Can any of you explain the diffrence between the various steels used for bicycles and their comparitive advantages? Example: A Lemond Zurich (DF) boasts a Reynolds 853 sticker on the frame. It seems as though all of the steel recumbents are 4130 chromoly. Thanks in advance. 853 has a higher strength to weight ratio, has better fatigue strength and stiffness (about 30% greater than 4130). 853 is still Reynold's best steel. The joints actually gain strength as they cool. 853 cannot be brazed, only welded. Reynolds makes a 4130 called Reynolds 525. It's a general all-purpose tube - less expensive than 853. R2 -- -------------------------- Posted via cyclingforums.com http://www.cyclingforums.com |
#4
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4130 Chromoly vs. Reynolds 853 Steel
The reason recumbents are done in 4130 is that a the tubing shapes and
sizes of a diamond frame bike do not cross over to a recumbent... yet. Diamond frame tubes are usually no longer then 2 feet. Some recumbent frames require 4 foot lengths. Diamond frames are fairly routine in their dimensions. In many cases, paint is all that makes one brand different from another. In recumbent land the frames are very different from one maker to the next. Change the paint and you will still know where the frame came from. 4130 is good, strong material that comes in many sizes and shapes. Perfect for the small manufacture. Speedy Bobinator wrote: Can any of you explain the diffrence between the various steels used for bicycles and their comparitive advantages? Example: A Lemond Zurich (DF) boasts a Reynolds 853 sticker on the frame. It seems as though all of the steel recumbents are 4130 chromoly. Thanks in advance. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
#5
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4130 Chromoly vs. Reynolds 853 Steel
(Mark Stonich) wrote in
om: rorschandt wrote in message news: Reynolds 853 is recommended to be used with lugged construction silver brazed methods. DEFINITELY NOT!!!! See; http://www.reynoldsusa.com/prop/853.html where you will see that silver brazing is on Reynolds' list of "Tips on what you MUST NOT do with Reynolds 853" Can't really argue with the Reynolds website! I don't know where I got the silver part(sorry!), but the rest is just quoting from the Bob Jackson website: "The main advantage of Reynolds 853 is its ability to air harden after joining, a characteristic not shown by other chrome molybdenum / manganese molybdenum materials presently on the market. When building frames using either TIG welding or high temperature brazing, above 1600 degrees, the joints increase in strength as the frame cools to room temperature. LUG CONSTRUCTION IS THE PREFERRED METHOD OF JOINING 853. It allows a much larger area to be heated than tig welding which concentrates the heat to a very small area at the weld. This completely goes against the “AIR HARDENING” building philosophy of the material and adds nothing to the strength of the joint. It is however a much cheaper joining method, requiring less time and skill to perform." I'm unlikely to be using the stuff myself. For now, 4130 crmo and 6061 and 7000 series aluminums serve my purposes fine. I have used chunks of heat hardening steels for other machined parts, not on frames. I wonder how they control the distortions in a "air hardened" tube? rorschandt |
#6
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4130 Chromoly vs. Reynolds 853 Steel
FWIW, interesting comment I saw posted recently on steel tubing:
"725 is Reynold's replacement for 753, it was introduced 4-5 years ago. It is a Chromium-Molybedenum steel alloy that is heat-treated. Its non heat-treated brother is 525 which is also the 531 replacement. 725 is a very desirable tubing, said to be nearly identical to the famous but sadly gone Tange Prestige tubing. Biggest advantage versus 753 is its heat tolerance. Its low carbon content makes 725 easily joined with silver, brass or even TIG welding, although it does suffer some annealing in heat effected area. Most importantly for ride and durability, 725 has much better elongation and ductility than air-hardened alloys thus maintains much of that resilience that tubesets like 531 and 753 were most noted for. I would avoid 853/653, Columbus Foco/Ultra Foco, Dedacciai 16.5 and True Temper OX Platinum/Gold -- these are in my experience rather "harsh or brittle" to borrow your phrasing." "Bobinator" wrote in message m... Can any of you explain the diffrence between the various steels used for bicycles and their comparitive advantages? Example: A Lemond Zurich (DF) boasts a Reynolds 853 sticker on the frame. It seems as though all of the steel recumbents are 4130 chromoly. Thanks in advance. |
#7
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4130 Chromoly vs. Reynolds 853 Steel
FWIW the frame of the late lamented Kingcycle was made from custom-ovalised
plain-gauge 531. Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/ ================================================== ========= Editor - British Human Power Club Newsletter http://www.bhpc.org.uk/ ================================================== ========= |
#8
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4130 Chromoly vs. Reynolds 853 Steel
General rules of metallurgy:
Stiffness is a function of elastic modulus. Just about all steel alloys have similar enough moduli that any difference would vanish into the noise. One should almost NEVER weld heat treatable steels, or any other heat treatable alloy for that matter, unless you are prepared to re-heat treat or accept the loss of strength in the base metal next to the weld joint. The weld may meet the strength of the original base metal but the heat from the welding will completely mess up the heat treatment of the base metal next to the joint. Furthermore in thick sections, nothing in bike manufacture is thick enough for this concern, it is required to heat the metal to red hot to prevent cracking of the base metal next to the weld joint. (Personal lesson learned here is to never simply tell someone to get the joint hotter than hell before welding unless you tell them how hot you think hell is.) Fatigue resistance and actual tensile strength is a function of the alloy, but it is also a function of the heat treatment. Also, the fatigue resistance of steels is relatively high. Minor changes can seriously affect the fatigue properties of aluminum alloys because it is is much lower, but steel is relatively tolerant. I'm not sure if you'll see any real differences here in a practical, rather than laboratory, situation. If there is any real differences, you might see some effect in corrosion resistance. An alloy that is tweaked to the limits of what it can do will corrode faster than one that is working in the center of its capabilities. 4130 Cr-Mo steel is used frequently because it is an old well-characterized alloy. It's commonly available, easy to manufacture, and in the kinds of section thicknesses you see in bikes, easy to heat treat. If you were willing to pay what it cost to make a custom titanium bike and end up with a steel bike, I could suggest some better steel alloys that, if you were the kind of rider that Fabrizio thinks he is, you might be able to detect the difference in performance. From a basic metallurgy standpoint only, the differences in alloys means they can charge you more money because they use their "custom" alloy rather than garden variety 4130. Racing strips would be about as effective. |
#9
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4130 Chromoly vs. Reynolds 853 Steel
R2D2 wrote: ... Because the air-hardened joints Increase in strength after welding, the overall stiffness of the frame is increased substantially (30% greater than 4130 Chrome-Moly is typical). I'm talking about a built frame here, not raw tubes. This is of course due to the fact that the 4130 joints will become annealed during the joining process. Now some may argue that the ride of a frame built with un-heat treated steel is much more forgiving (softer), and thus preferable. The increase in strength at the joints will not effect elastic modulus significantly. You are confusing two different things here. It would take precision equipment to measure the difference in elastic modulus between Reynolds 853 (before or after heat treatment) and 4130 Cro-Moly. In practical terms there is no difference. I'm not saying that an 853 frame is ultra-stiff by any means. My aluminum DF Klein MTB would be considered ultra-stiff. Klein heat treats the entire frame post welding. The energy transfer from pedal to wheel is simply amazing. This has to do with the size and wall thickness of the tubing and the frame geometry - heat treating the frame after welding affects tensile strength but not elastic modulus. Jim's advice here pertains to un-heat treated tubes (like the 4130s), and not the heat-treated 853.... Jim is correct about there being no appreciable difference in the elastic modulus of the two steels. Tom Sherman - Quad Cities USA (Illinois side) |
#10
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4130 Chromoly vs. Reynolds 853 Steel
First before I say anything, I've just had knee surgery to correct a
problem with my knee that's prevented me from cycling for about 10 years and I'm only on the newsgroup because my wife's about to buy a Streetmachine. Now that I've admitted to having no credentials at all about frame building, discussions on this this newsgroup seem to imply that the frame performance is mostly based on stiffness. Once the frame is strong enough to deal with the abuse life throws at it, a stronger frame is unimportant. The stiffer a frame gets the more cycler power can be applied more efficiently (I realize that there was a discussion about having too stiff a frame). If I'm correct about that, frame stiffness is again a function of modulus and does not include tensile strength at all. All steels from 1020 plain carbon steel to the special through harndening tool steels have close enough moduli that you day to day variation in cycling will swamp the small change in cycling performance. Tensile strength is only important when that cyclist hits a bump/curb/car/etc and it's time to decide how badly the bike gets bent. Second question, titanium and aluminum are rarely selected because of their strength to weight ratios. They tend to be cited for their excellent stiffness to weight ratios. If you are not constrained in tube thickness, titanium or aluminum alloys can match the stiffness of a steel bike with a fraction of the weight. The also tend to have tend to have shorter fatigue lives and fun corrosion modes (if it's fun for the metallurgist, it's not fun for the user). Saying that a steel has the same strength to weight ratio as titanium is nice, but I still think that stiffness(modulus) is the driving property and there isn't a steel in existence that matches aluminum or titanium in modulus to weight ratio. I'm probably not going to change anyone's mind, but I'll give the official metallurgy party line: Don't weld heat treatable steels without giving them a post-weld heat treatment or understanding the loss of strength caused by welding. The base metal isn't simply annealed. The base metal has melted next to the weld joint (melting the base metal is the definition of welding rather than brazing). That metal has now converted to martensite; really strong and really brittle. The base metal that didn't melt but is next to the weld is fully annealed and likely to be dead soft for the base metal. The area that didn't get fully annealed is over-tempered and much weaker then it should be, and so on out from the weld until you reach unaffected base metal. There are ways to get a mechanically reinforced joint so this doesn't matter, but welding on a heat treated steels is generally a bad idea. |
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