Experimental investigation of the flat clinch–rivet process

In recent years, lightweight materials with high mechanical property and low density have been more and more widely used in aerospace, automotive and other industries. The mechanical self–piercing riveting technique is appropriate for joining these lightweight materials. However, the plate under the self–piercing riveted joint will make a bulge, which greatly limits the application of the mechanical riveting technique. A new joining technology, flat clinch–rivet process (FCRP), is proposed to solve the problem of lower plate protrusion in this paper. The experimental results show that flat clinch–riveted joints formed under greater forming forces have better joining quality. Both the neck thickness and the interlock value will increase with the increase of forming force. When the riveting force is 150 kN, the tensile strength and shear strength of the flat clinch–riveted joint is 2 kN and 4.2 kN, respectively. In the strength test, the pull-off failure mode of the neck is the main failure mode. The tensile strength, shear strength and failure energy of the flat clinch–riveted joint are higher than those of the flat–clinching joint. Experimental results show that the joining method is reliable and effective.