Friction hydro pillar processing is a new process developed to repair surface and under surface cracks. In this process, a rotating stud is used to fill a groove created on a plate with the same material. Temperature field
plays an important role in this process. Hightemperature makes it possible for material to flow and fill the groove. On the other hand, material flow is importantto enhance the defect-free refilling of the groove. In this paper, friction hydro pillar processing was simulated by finite element method using DEFORM V11 software. The temperature field and material flow were modeled successfully. The highest temperature, load and stress were calculated to be 1580 ºC, 202 kN, and 641 MPa, respectively. It was concluded that the stud material playsmore significant role in the mixing and welding phases. Relatively a big heat affected zone was found there which might lead to problems such as softening of the periphery of processed zone.