Abstract
Friction stir welding is a newly developed solid
state welding process, which was developed by The Welding
Institute in the year 1991. The development of FSW has
allowed the process to be used in different applications for
different industries, which include aerospace and automobile
industry. Due to the increase in the demand of high strength
and low weight components in different manufacturing
applications, there is a need for using pure aluminium and its
alloys in lap configuration. Research studies are required to
characterize and obtain optimum process parameters, which
can be used to produce good quality lap welds. This paper
reports lap welded 1050 Aluminium Alloy using friction stir
welding process and established the effect of rotational speed
on the joint integrity of the welds. The welds were produced by
varying the rotational speed in the range of 1200 and 2000
rpm, and maintaining the traverse speed constant at 150
mm/min. The welds were characterized through
microstructural evaluation, microhardness profiling and
tensile testing in order to determine the joint integrity of the
welds. The results from the macrograph of the welded joints,
show a basin shaped nugget resulting from the stirring of the
tool during the welding process. Fine and equiaxed grains
characterized the microstructure in the stirred zone, which
was a result of a dynamic recrystallization. The tensile test
data revealed that as the tool rotational speed was increased,
the fracture strength also increases, the highest value of the
fracture strength was 195 N/mm and was found on the welds
produced at 2000 rpm. High Vickers microhardness values
were measured at the nugget zone with the highest value found
to be 31.88 HV. It was revealed that the welds produced at the
rotational speed of 2000 rpm exhibited the optimum welding
parameters to join 1050 Aluminium Alloy.