Loading...

Spot Resistance Welding of St12 and HSLA Steels in Different Thicknesses

Farhangdoust, Sajad | 2009

1132 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39944 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Kokabi, Amirhosein; Ekrami, Aliakbar
  7. Abstract:
  8. High-strength low alloy (HSLA) E275 developed specifically for automotive application. Also St12 Steel is used in autobodies. On the other hand the resistance spot weld of dissimilar materials is generally more challenging than that of similar materials due to differences in the physical, chemical and mechanical properties of the base metals. The influence of the primary welding parameters affecting the heat input such as; current and time on the morphology, fracture mode, microhardness, and tensile shear load bearing capacity of dissimilar welds between HSLA E275 steel and St12 steel in two different thicknesses (1,2 mm) has been investigated in this study which consisted six group. The weld lobes (the optimum weld parameters) for each of that six group based on welding current and time were established, where electrode force was kept constant. Then, minimum required weld diameter that guarantees the pullout mode failure based on sheet thickness was established. Finally, microstructural characteristics were investigated by using stereograph microscope, optical microscope and SEM. Due to nature of process and also the high hardenability of HSLA steel the weld metal completely consisted of martensite. The hardness in the weld nugget was observed to be between two to three times higher than that in the base metal due to the formation of martensite in all six groups
  9. Keywords:
  10. Welding ; Resistance Spot Welding ; Plain Carbon Steel ; High Strength Steels ; Low Alloy Steels ; Different Compounds ; Different Thicknesses

 Digital Object List

  • محتواي پايان نامه
  •   view

 Bookmark

No TOC