stainless steel  ACR welding studs /welded studs 

size M6x20 

stud Welding is a general term for joining a metal stud, or similar part, to a work piece. Welding can be done by a number of welding processes including ARC, Resistance, Friction and Percussion. Of these processes, STUD ARC WELDING utilizes equipment and techniques unique to stud welding. The other processes use conventionally designed equipment with special tooling.

Mild steel, stainless steel and aluminum are applicable materials for Arc Welding.
1: A fastener and ceramic ferrule are firmly placed against the work surface under spring tension.
2: Upon triggering, the weld gun automatically lifts the fastener from the base metal and initiates a controlled electric arc - which melts the end of the fastener and a portion of the base metal.
3: A ceramic arc shield concentrates the heat and retains the molten material in the weld area for maximum weld strength and reliability.
4: At the precise moment the fastener and the parent metal become molten, the fastener is automatically plunged into the work surface. The metal solidifies and a high quality fusion weld is completed.

Drilling & Tapping
These processes are very slow. Thicker parent material is required, as are longer studs.

Inserts
Can eventually work loose. They can also crack paint and leave unsightly stains. Holes need to be punched and deburred in parent material. The reverse side is not always clean and flat. The parent material is weakened by the holes.

Back Welding
The process is slow. Holes need to be punched and deburred in parent material. The excess weld needs grinding off, for a clean, flat finish. The parent material is weakened by the holes.

Through Bolting
Requires two handed assembly and access from both sides. Holes need to be punched and deburred in parent material. Bolt heads are unsightly and stains can come from the bolt holes. The assembly is not leak-proof and the parent material is weakened by the presence of the holes.