TWI Industrial Member Report Summary 720/2001
S A Westgate
Self-piercing riveting is used for the high speed mechanical fastening of sheet material components without pre-drilled holes. It is suitable for joining dissimilar materials, as well as coated and painted materials for which resistance spot welding cannot be used. It can also be used to join some plastics to metals. The equipment is suitable for automation and is similar in its speed of operation to spot welding. Consequently, there is particular interest in the automotive industry.
Self-piercing riveting has seen rapid development and is being used in a range of applications. Much of the data on joint performance has been generated in specific application studies but some work has been conducted to provide more generic data. The mechanical properties of self-piercing riveted joints in aluminium alloys can exceed those of spot welds and, even in thin sheet steel, the fatigue performance of self-piercing riveted joints is usually better than spot welds.
TWI's work in this area has included a comparison of self-piercing riveting with clinching and spot welding for a range of material combinations, and studies of the static and fatigue performance of self-piercing riveted and hybrid joints.
For reliable use, information is required in the following areas:
- Joint performance
- Quality control and testing
- Process variability
Joint performance data is normally established for the particular application and depends on the materials and the rivet type chosen. Other areas of quality control, testing and process variability are fundamental to all applications. As there is little standardisation and only limited practical process information, this report attempts to review the available information and provide guidance on setting up and optimising the process. Most of the work has been conducted on steel and aluminium alloys but the principles are applicable to a wider range of combinations.
The report outlines the quality control, testing and monitoring of self-piercing riveted joints. It then reviews the factors affecting joint quality, indicating their potential influence on process variability. This work formed part of a European CRAFT Programme concerning self-piercing riveting and hybrid joining techniques (SPRYTE).
- To provide guidance on quality control, testing and monitoring of self-piercing riveted joints
- To review the factors affecting the quality of such joints, to determine the significant production factors and their potential effect on process variability