Friction welding is a process of joining materials by utilizing pressure and heat obtained from the friction results of both surfaces of the object. This study aims to know the influence of friction strength on tensile properties, microstructure, and hardness on the connection of friction welding. The material used in this research is stainless stell 304 pipe. Material cut along 72 mm using hacksaw. Parameter used in this research is with variation of friction strength 30 MPa, 32,5 MPa, and 35 MPa. Rotation speed at constant friction welding machine is 1000 rpm. Tests conducted in this study are the testing of tensile strength, metallographic testing, and hardness testing. The result of this research is the increasing of friction strength given the grain size of the micro structure of the friction welding interface area decreases and the hardness of intetface area becomes bigger. The highest hardness of interface area is found in the variation of 35 MPa friction strength that is 270,9 VHN, the lowest hardness at 30 MPa friction strength is 226,01 VHN. The result of highest tensile strength at friction pressure of 30 MPa is 503 MPa but still lower than result of tensile strength at raw material that is equal to 645 MPa.