Abstract
In recent years, interest on friction stir welding has grown more since such a joining technique allows welding of light weight alloys like aluminum and its alloys which are difficult to weld or even unweldable with the traditional fusion welding processes. This process can also be one of the joining processes considered for welding polymer matrix composites such as polypropylene composites which find a number of applications in different industries. This paper presents the effect of tool pin profile on surface appearance and tensile shear strength of friction stir lap welds in carbon fiber reinforced poly- propylene composites with 4 mm thickness. Four high speed steel tools with different pinprofiles of threaded cylindrical, threaded cylindrical-conical, simple cylindrical-conical and threaded conical were employed for this study. Using these tools, lap welds were made under similar conditions of tool rotational speed, welding speed and tilt angle. Specimens were prepared for tensile shear testing. The tensile shear test results showed that the threaded cylindrical-conical tool produced a weld with better surface appearance and higher tensile shear strength.
Highlights
Fiber reinforced thermoplastic composites have beenintroduced as structural materials for high performanceapplications because of their many advantages such as improved toughness, good mechanical properties, lowdensity, resistance to chemical reaction, recyclability, high temperature strength and infinite shelf life
Tool number 4 whose pin is threaded conical, creates lesser contact surface with the work piece compared with tool number 1, which causes the quality of the weld surface (Figure 7-d) in tool 4 to decrease in comparison to that of tool 1 because lesser heat and friction are generated at the contact area
By keeping constant parameters such as rotational speed, welding speed and tilt angle, it was observed that the tool pin profile has a significant effect on the surfaceappearance and weld strength.It was observed that tool number 2 produced a weld without any surface porosityand voids with better tensile shear strength in comparison to other tools
Summary
Fiber reinforced thermoplastic composites have beenintroduced as structural materials for high performanceapplications because of their many advantages such as improved toughness, good mechanical properties, lowdensity, resistance to chemical reaction, recyclability, high temperature strength and infinite shelf life. The results showed that, for thin sheets, the best joint has been produced by a shoulder with cavity and fillet.Kumar et al.[9] studied the effect of tool pin profile onmicrostructural development and mechanicalproperties of friction stir welded precipitation hardenable Al-Zn-Mg alloy in the thickness of 4.4 mm and concluded that joints welded with frustum-shaped rounded-end pin profile had better mechanical properties compared to cylindrical flat-end pin profile. It is tried to examine the effect of welding parameters on surface appearance and tensile shear strength of lap joints of PP composites with 20% CF as influenced by the tool pin profilewhile keeping rotational speed, welding speed and tilt angle fixed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
