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Materials selection - properties. Materials selection - properties. Materials selection - properties. Materials selection - environment. Bicycle frames. Bicycle frames. Bicycle frames – hot piercing for seamless tubing. Bicycle frames – cold drawing of seamless tubing. - PowerPoint PPT Presentation
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Materials selection - properties
Materials selection - properties
Materials selection - properties
Materials selection - environment
Bicycle frames
Bicycle frames
Bicycle frames – hot piercing for seamless tubing
Bicycle frames – cold drawing of seamless tubing
Cold drawing – need high formability
––> extensive work-hardening
Bicycle frames
Bicycle frames
Bicycle frames – common materials used
density modulusPlain carbon steel 7.8 gm/cc 200GPaCr-Mo steel 7.8 2006061–T6 2.7 70Ti-3Al-2.5V 4.5 110Polymer composite
yield yield/densityPlain carbon steel 240 MPa 30Cr-Mo steel 485 626061–T6 260 95Ti-3Al-2.5V 700 156
A little bit more on Ti and its alloys
Ti is polymorphic: -Ti (hcp) ––> -Ti(A2) at 882°CTi mostly alloyed with Al, V
Remember - & -Fe w/ chromium, & nickel
Various elements have different solubilities in - & -Ti
A little bit more on Ti and its alloys
Ti-3Al-2.5V is an "- alloy"
Enuf -stabilizer (V) added so that a little phase can exist at room temp
& phase solution strengthened by Al & V
alloys are stronger than those containing only or phase
Joining techniques
Conventional arc welding
Tungsten inert gas (TIG) welding Brazing
Adhesive bonding
Joining techniques
Plain carbon steel frame – TIG welded
Tubing is strengthened by drawing operation –but softened near weld
Use butted tubing for strengthening HAZ region
Joining techniques
Cr-Mo steel frame – TIG welded
But weld and HAZ harder than tubing – more rapid cooling than that experienced by tubing – get Bainite
original tube