| 摘要 |
PROBLEM TO BE SOLVED: To provide a different material joint forging rivet made of steel, which is molded by a forging work from a material, to have an insulator layer (a membrane having a higher resistance than that of the steel material) on a surface, wherein the insulating layer formed on the rivet is not peeled when the rivet is driven into a light alloy material, thereby to prevent an electric current at a spot welding time from flowing into the light alloy material.SOLUTION: A different material joint forging rivet comprises a tubular head 2 and a shank 3. The shank 3 includes: a first shank 4 extending from the head 2; an annular protrusion 5 protruding in an outer circumferential direction at a tip of the first shank 4; and a second shank 6 having a smaller sectional area than that of the first shank 4 and further extending in a tip direction from the protrusion 5. An insulating layer 9 is formed on surfaces of the shank 2 and the head 3 (faces to contact with said light weight material when driven into said light alloy material).SELECTED DRAWING: Figure 1 |
