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A summary on materials selection

A summary on materials selection. Some of the major factors in the selection of materials are Strength of the material Corrosion resistance of the material Joinability of the various pieces Formability into the appropriate shapes Fracture toughness

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A summary on materials selection

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  1. A summary on materials selection Some of the major factors in the selection of materials are Strength of the material Corrosion resistance of the material Joinability of the various pieces Formability into the appropriate shapes Fracture toughness Cost of alloy plus fabrication costs Tubing for bicycle frames is made by hot piercing the ingot and then subsequently cold drawing using a mandrel to make the hole in the tubing and get the correct diameter and wall thickness. Cold drawing of the material causes it to become work hardened Possible materials for the manufacture of a bicycle frame and some interesting properties are yield yield/density Plain carbon steel 240 MPa 30 Cr-Mo steel 485 62 6061-T6 260 95 Ti-3Al-2.5V 700 156

  2. Al alloy 6061 has the composition Al-1.0Mg-0.6Si. It is precipitation or age hardenable. The heat treatment procedure is to solution treat the tubing at 530° C, then quench it, and subsequently age it at 160° C for 18 hrs. The precipitate which forms upon this ageing treatment is Mg2Si. These second phase particles hinder the motion of the dislocations inside the material, and the yield strength is thus increased from 8 to 40 ksi. Titanium is polymorphic and changes its crystal structure at 882° C The two most important elements for the alloying of titanium are aluminum and vanadium.

  3. Ti alloys strengthened by

  4. Ti alloys strengthened by solution hardening

  5. Ti alloys strengthened by solution hardening mix of a & b phases

  6. Ti alloys strengthened by solution hardening mix of a & b phases heat treating (Q & age)

  7. Ti alloys strengthened by solution hardening mix of a & b phases heat treating (Q & age) martensite transformation

  8. Ti alloys strengthened by solution hardening mix of a & b phases heat treating (Q & age) martensite transformation EXCELLENT corrosion resistance

  9. Ti alloys strengthened by solution hardening mix of a & b phases heat treating (Q & age) martensite transformation EXCELLENT corrosion resistance Oxygen sponge at moderately elevated temps

  10. Ti alloys strengthened by solution hardening mix of a & b phases heat treating (Q & age) martensite transformation EXCELLENT corrosion resistance Oxygen sponge at moderately elevated temps Expensive

  11. Ti alloys strengthened by solution hardening mix of a & b phases heat treating (Q & age) martensite transformation EXCELLENT corrosion resistance Oxygen sponge at moderately elevated temps Expensive Joining: arc welding, TIG, brazing, adhesive bonding

  12. Ti alloys strengthened by solution hardening mix of a & b phases heat treating (Q & age) martensite transformation EXCELLENT corrosion resistance Oxygen sponge at moderately elevated temps Expensive Joining: arc welding, TIG, brazing, adhesive bonding Welding gives HAZ with properties different than base material

  13. Cr-Mo steel frame: weld and HAZ are bainite

  14. Cr-Mo steel frame: weld and HAZ are bainite TIG welded 6061-T6: weld & HAZ overaged

  15. Cr-Mo steel frame: weld and HAZ are bainite TIG welded 6061-T6: weld & HAZ overaged

  16. Cr-Mo steel frame: weld and HAZ are bainite TIG welded 6061-T6: weld & HAZ overaged Brazing: furnace-brazed w/ Cu-Zn alloy at 900° C - frame softened

  17. Cr-Mo steel frame: weld and HAZ are bainite TIG welded 6061-T6: weld & HAZ overaged Brazing: furnace-brazed w/ Cu-Zn alloy at 900° C - frame softened Adhesive bonding: low T & design change

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