A three-dimensional thermo-mechanical finite element model (FEM) is developed to study the feasibility of hybrid friction diffusion bond bonding HFDB technique for welding tube-tubesheet joints. The FEM was developed and solved using Abaqus/explicit. Considering the process thermo-mechanical nature, temperature dependent material properties and Johnson-cook model were adopted. Two tube-tubesheet configuration were considered in the numerical study; flush and projected. For validation purposes, HFDB of tube-tubesheet was experimentally performed for 19 mm (¾ in) ASTM 179 cold-drawn carbon steel tube into ASTM A516 Grade tubesheet considering flush tube. The tool/workpiece temperature was measured using infrared camera, and produced joints were sectioned and examined under optical microscope. Good agreement between estimated temperatures and deformation with experimental results were found. According to FE results, spring back of tube was found to negatively affect the joint integrity. Also, contact stresses during processing phase were found less in the projected tube as compared to the flush one.