Bolt element having a shaft part and a sherical head, component assembly and method for the manufacture of a bolt element

A functional male element of metal adapted for use with a metal panel element of steel of drawing quality and having a thickness, and comprising:

• a shaft part;
• a head part axially aligned with said shaft part and forming a hollow tubular wall adapted for forming a riveting joint with a panel element;
• said male element being formed of a material which in the context of cold de formation achieves the strength values of class 5.6 in accordance with the ISO standard,
• wherein said shaft part defines a shaft diameter and said tubular wall defines an outer wall diameter corresponding to said shaft diameter, said head part merging into said shaft part without a panel-element-contacting flange;
• wherein said head part includes a distal end defining an outer edge and an inner edge defining a conical surface remote from said shaft part and diverging in a direction going from said shaft part to a free end of said head part;
• said head part having a longitudinal dimension and tubular wall thickness, wherein, in use and under the action of pressing forces applied to said shaft part, said distal end of said head part operating in conjunction with a die button supporting said metal panel element is passed through a pre-formed hole in said metal panel element and wherein said tubular wall thickness and said longitudinal dimension are selected so that said longitudinal dimension forms an annular fold defining a panel-element-contacting flange and having a radially-outwardly directed portion and a radially-inwardly-directed portion contacting said metal panel element, said longitudinal dimension being sufficient length to also include a length of the head part in the metal panel element and a length of a rivet flange formed on an opposite side of said metal panel element from said panel-element-contacting flange.