Friction Spot Joining Technology for High Tensile Strength Steel

High tensile strength steel is becoming more widespread as a material used for reducing the body weight of automobiles. However, there is an issue when high tensile strength steel is used in that it becomes impossible to guarantee quality with conventional spot welding, as its strength decreases at joints due to its high carbon content.
To solve this issue, we are working on technological development to apply our proprietary metal joining technology "Friction Spot Joining" (FSJ*), which has already been put into practical use for joining aluminum alloys, to high tensile strength steel.
In the FSJ method, plates are joined by pressing the special tool against the superposed steel plates with immense force while it rotates at high speed. Thus, great durability is required of the tool.
We have extended the life of this tool by using a special carbide material and applying a special coating over its surface to optimize the joining condition. As a result, we have been able to ensure the same level of quality as that achieved when a general steel plate is joined using spot welding, without having any problem even after joining more than 10,000 locations. We have thus made a great advancement toward the practical application of this technology.

* FSJ ： Friction Spot Joining

FSJ robot system