Silver Tubing Info

[John Hawrylak]

Does anyone have a link to the RBW Silver Tubing sticker which gives the mechanical properties of the tubing.  I seem to recall 110 ksi UTS.  I looked on the RBW site and searched but came up empty.

John Hawrylak

Woodstown NJ

[Benz, Sunnyvale, CA]

On Sunday, September 17, 2017 at 1:01:21 PM UTC-7, John Hawrylak wrote:

Does anyone have a link to the RBW Silver Tubing sticker which gives the mechanical properties of the tubing.  I seem to recall 110 ksi UTS.  I looked on the RBW site and searched but came up empty.

It's here, in the announcement for Le S!lver crank.

Basically, it says:

• S!lver butted Cr-Mo steel tubes, forks, stays
  
• Fe 97.3%
  
• Cr 1%
  
• Mo 0.2%
  
• C+Mn+Si+S 1.5%
  
• UTS ~103,000 psi
  
• Elongation ~10%
  
• Yield ~70,000 psi
  

Kind of in the same ballpark as the evergreen Reynolds 531.

[Bob Ehrenbeck]

Here's a photo of the actual tubing sticker that's on my Clem:

https://flic.kr/p/AKBQJU

Bob E

Cranford, NJ

[Lee Legrand]

Had no idea steel tubing had a yield strength of 70ksi. Stronger than typical rebar used in concrete buildings.

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[John Hawrylak]

Yes, RBW claims it is heat treated, but the UTS is very close to True Temper Versus (110,000 psi) so the heat treatment is probably for stress relief instead of increasing the UTS

John Hawrylak

Woodstown NJ

[Lee Legrand]

Hi John,

I assume the UTS is ultimate tension strength or stress. I would think the bicycle builder or framer would want it to be less than 70ksi (yield strength limit).  Once stress exceed the yield strength, it will basically begin to fail due to buckling or plastic hinge effects happen on the frame.  Deformation in the steel is plastic instead of elastic once it exceeds yield.

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[John Hawrylak]

Lee

I agree, the yield stress reflects the max for design, you want to keep the stress in the elastic region.   Typically Yield increases proportionally as UTS increases, e.g., a Columbus Niobium tube has a UTS = 152 to 167 ksi with a Yield = 107 ksi.  The Columbus has a 55% higher yield and 53% higher UTS than the RBW Silver tube.  Also the Niobium is slightly more ductile, >14% elongation vs >10%.

So RBW tubing is not the highest strength, but seems adequate for a lugged frame.  It is difficult to see the RBW claim of being less brittle than heat treated steels

John Hawrylak

Woodstown NJ

On Monday, September 18, 2017 at 6:50:37 PM UTC-4, Lee Legrand wrote:

Hi John,

I assume the UTS is ultimate tension strength or stress. I would think the bicycle builder or framer would want it to be less than 70ksi (yield strength limit).  Once stress exceed the yield strength, it will basically begin to fail due to buckling or plastic hinge effects happen on the frame.  Deformation in the steel is plastic instead of elastic once it exceeds yield.

On Mon, Sep 18, 2017 at 6:23 PM, John Hawrylak <John.H...@verizon.net> wrote:

Yes, RBW claims it is heat treated, but the UTS is very close to True Temper Versus (110,000 psi) so the heat treatment is probably for stress relief instead of increasing the UTS

John Hawrylak

Woodstown NJ

On Sunday, September 17, 2017 at 10:36:16 PM UTC-4, Benz, Sunnyvale, CA wrote:

On Sunday, September 17, 2017 at 1:01:21 PM UTC-7, John Hawrylak wrote:

Does anyone have a link to the RBW Silver Tubing sticker which gives the mechanical properties of the tubing.  I seem to recall 110 ksi UTS.  I looked on the RBW site and searched but came up empty.

It's here, in the announcement for Le S!lver crank.

Basically, it says:

• S!lver butted Cr-Mo steel tubes, forks, stays
  
• Fe 97.3%
  
• Cr 1%
  
• Mo 0.2%
  
• C+Mn+Si+S 1.5%
  
• UTS ~103,000 psi
  
• Elongation ~10%
  
• Yield ~70,000 psi
  

Kind of in the same ballpark as the evergreen Reynolds 531.

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[Chris Lampe 2]

Interesting discussion on a topic I know nothing about.  My 84 Trek with Reynolds 501 ATB tubes has a sticker that says   "120,000 PSI Strength"      How is that interpreted?   Is that enough information to even know anything about it's strength?

[Lee Legrand]

Hi John,

Yield strength and UTS is typically fixed in material. If I am understanding what you have written so far, RBW from a liability standpoint would design bicycle frames to not exceed 107 ksi. Any stress past this point would result in a deformed frame although capacity is still there.  Also consider that there are two failing mechanism within a bicycle frame which are tensile and compression. Compression failure due to buckling would be the most critical of the two and would set the criteria of acceptable stress to be in the frame to be much lower than 107 ksi when loaded by a rider.

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[John Hawrylak]

Chris

I suggest it is the UTS, the stress where it breaks.  TT Versus has a UTS of 110,000 psi (1ksi = 1,000 psi).

John Hawrylak

Woodstown NJ

[John Hawrylak]

Lee

I agree on your compression remarks

On UTS and Ys, I was only pointing out heat treatment affects both the UTS and the Ys.  So when vendors show increased UTS due to either heat treatment or a slight change in alloying, or both, the UTS and Ys increase.

I think the real question is how strong do you need it to be.  Grant touched on this point in a recent blug.  For example, using 853 vs 753 for a lugged frame with 0.7/0.4/0.7 mm wall thicknesses, may not  do anything more than increase your margin for safety.  It may also be cheap to do, so why not use the stronger (perceived as better) 853.

John Hawrylak

Woodstown NJ

[Lee Legrand]

Hi John,

I understand.

Thanks,

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[Grant @ Rivendell]

We have both HT and non-Heat Treated SILVER tubing...and one of my BLAHG posts within the last 5 weeks had an explanation. On the Taiwan frames we use non-HT tubes, which are better (for reasons explained in the post). For the American frames we use HT, because there's a belief (that I don't buy) that HT is better, and if we use nonHT on frames that cost $2K+, some people will say, "Aha!" for the wrong reason. Our Taiwan frames are tested rigorously, vigorously, to tough standards and they pass. When tested TO DESTRUCTION, they don't fail because of insufficiently strong tubing.

UTS (Ultimate Tensile Strength) is the "glory score" of bike frame tubing, but oddly so, because it literally, actually, is a measure of the force required to pull the material apart in tug-o-war...and that is not how bike frame tubes are stressed. But it correlates with other forces that ARE imposed on ridden bike frames...but the correlation isn't perfect and is misleading...as the BLAHG  post stated. I am not in proper mental/emotional/wrist pain from typing state right now to dig in and find that post, but ... it's out there, and what I've said here is the short version. All good fun things to discuss!

On Sunday, September 17, 2017 at 1:01:21 PM UTC-7, John Hawrylak wrote:

[Scott McLain]

Steel is such great stuff! Using alloys and heat treating you change the properties all over the place. Sometimes overlooked are infinite cycle life and that it work hardens unlike copper and aluminum that work softens, which i try not to think about when riding on 40 year old airplanes and another reason it sucks for bike frames. What I really like about Rivendell is that if you get all spun out on alloy numbers or heat treating on you bike tubes, you can call Grant and he can talk you off the ledge. That also goes for diets and care and feeding of your hatchet.

Steel is definitely one of the overlooked innovations that was necessary to feed the industrial age and what made America great! Oops , I meant really good. I think it was a bridge over the Mississippi and then the Brooklin bridge followed by the golden gate that drove the real innovation s in steel production.

Obsessing can be fun, but can also be unhealthy. Just ride!

Scott