Friction welding of S15CK carbon steel was carried out in order to examine the relationship between heat input for welding and joint strength. The joint strength is evaluated from tensile strength. The heat input is a heat source for welding solid materials and was classified into 6 inputs: friction heat input, deformation heat input and total heat input in the friction stage and upset stage.
The most important heat input for evaluating the joint strength among these heat inputs was experimentally investigated through the tensile strength of joints welded under various welding conditions.
As a result, it was made clear that the deformation heat input in the upset stage is much strongly related with the joint strength, and sound weld joints can be obtained deformation heat inputs more than about 100J/s. Moreover, it was recognized that the joint strength is possible to evaluate by the upset loss, therefore, sound welded joints can be obtained with about 1.2 mm upset burn-off length or more also.
