Friction stir spot welding with a consumable sheet (FSSW-C) is an advanced, sustainable method for welding dissimilar alloys, effectively tackling tool wear. Here, the tool engages a consumable sheet above base sheets, separated by gap at the edges. A pin-less tool stirs and softens the consumable sheet with frictional heat, and forging pressure pushes material into the gap, bonding with base sheet edges. Preventing tool wear is a key advantage. This study compares FSSW-C to conventional FSSW through finite element simulations using DEFORM 3D. Both methods are tested at rotational speeds: 612, 900, and 1200 rpm. FSSW-C shows an 18% lower peak temperature. As rotational speed rises, both the processes show increased effective strain and strain rates. FSSW-C consistently reports higher effective strain and strain rates, signifying superior material flow behavior and enhanced material distribution.