Method of manufacturing a welding stud
The invention relates to a method of manufacturing a welding stud from a wire by cold-working and by hardening and tempering. The welding stud particularly serves to be welded to a workpiece by means of an electric stud welding method and consists of a mounting portion and a welding portion. According to the invention, the wire is first pre-treated by hardening and tempering and is then cold-worked in such a way that the mounting portion and the welding portion have different strengths.
1. A method of manufacturing a welding stud from a wire having a mounting portion and a welding portion capable of being welded to a workpiece by an electric stud welding device comprising the steps of:
cutting said wire to a form a stud having a predetermined length;
pretreating said wire to increase hardness; and
cold working said mounting portion of said stud, wherein said mounting portion includes a higher hardness than said welding portion.
2. A method as set forth in claim 1 further including the step of reducing a diameter of said wire at said mounting portion to a mounting portion diameter being smaller than a welding portion diameter.
3. A method as set forth in claim 2 wherein said step of reducing said diameter of said mounting portion relative to said welding portion is further defined by increasing the strength of said mounting portion relative to said welding portion.
4. A method as set forth in claim 1 wherein said step of cold working said stud is further defined by reducing said diameter of said mounting portion to approximately 40% to 60% of said wire diameter.
5. A method as set forth in claim 1 wherein said step of cold working said stud is further defined by reducing said diameter of said welding portion to approximately 15% to 25% of said wire diameter.
6. A method as set forth in claim 1 wherein said wire is further defined as heat tempered steel.
7. A method as set forth in claim 1 wherein said wire is further defined as a non-heat treated, microalloyed steel.