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.
On Tue, Sep 19, 2017 at 6:29 PM, John Hawrylak <john.hawry...@verizon.net> wrote: > 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 >>>> <https://cdn.shopify.com/s/files/1/1403/7343/files/APPA_SILVER_DECAL_large.jpg?v=1489610838>, >>>> in the announcement >>>> <https://www.rivbike.com/blogs/peeking-through-the-knothole/le-sliver-carnk> >>>> 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. >>>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "RBW Owners Bunch" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to rbw-owners-bun...@googlegroups.com. >>> To post to this group, send email to rbw-owne...@googlegroups.com. >>> Visit this group at https://groups.google.com/group/rbw-owners-bunch. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- > You received this message because you are subscribed to the Google Groups > "RBW Owners Bunch" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to rbw-owners-bunch+unsubscr...@googlegroups.com. > To post to this group, send email to rbw-owners-bunch@googlegroups.com. > Visit this group at https://groups.google.com/group/rbw-owners-bunch. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at https://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
