Abstract
Continuous drive rotary friction welding was used to weld identical AISI 316L austenitic
stainless steel; and AISI 316L to AISI 304 austenitic stainless steel joints in this
investigation. The main aim was to evaluate the effect of rotary friction welding process
parameters on joint quality of similar and dissimilar rods with diameters of 12.5 mm. Burnoff,
friction time, and forging time were kept constant while rotational speed, friction
pressure, and forging pressure were varied, and these conditions were applied to all samples.
Optical microstructure (OM), scanning electron microscopy (SEM), and micro-hardness tests
were used to study the effect of process parameters on the quality or strength of welded
connections. Energy Dispersive Spectroscopy (EDS) was used to examine the chemical
composition of the welds.
The results show that the process parameters that were changed during the friction welding
process caused the variation in hardness and microstructure in the interfaces of the welded
joints. Low rotating speed of 1500 rpm and friction pressure of 6.22 kN were discovered to
cause voids or lack of bonding at the welded joint surfaces. Welds created at high rotation
speed (2100) and friction pressure (8.48 kN) were discovered to have good quality joints
without defects. The increase in these two parameters during rotary friction welding has
resulted in highest micro-hardness value of 215 HV in similar (316L) weld zone (WZ).
Microstructure analysis indicates that Base Material (BM) had ferrite and twin grains
microstructure, the Heat Affected Zone (HAZ) had coarse grains while Weld Zone (WZ)
consisted of less austenite and more ferrite. The coarse grains were caused by the increased of
heat input in HAZ. The grains were refined near the interface and deformed in the heataffected
zone. As the parent material (PM) was not impacted by the friction heat generated
during the welding process, it comprised of un-deformed equiaxed grains.