RF Ceramic Ferrules for Weld Studs with Reduced Shaft (Type RF as per ISO 13918) Cordierite Ceramic Ferrules for Stud Welding

Ceramic Ferrules for Weld Studs with Reduced Shaft (Type RF as per ISO 13918)

Type RF ceramic ferrules are used for type RD weld studs.

Ceramic ferrules (also known as ceramic arc shields) are small rings made from ceramic material. They ensure the drawn arc stud welding process works effectively. Without ceramic ferrules, the drawn arc process wouldn’t be effective and welds wouldn’t be as strong. To understand why, it’s important to know how drawn arc stud welding works.
Drawn Arc Welding
Firstly, the drawn arc machine is set up for the appropriate stud diameter. The stud is then placed on the plate ready to be
welded. Once the process is triggered, the stud is lifted slightly from the plate and a pilot-arc is triggered. This is followed by the main arc which melts the tip of the stud into molten metal. It creates a metal pool on the plate. The machine then return-springs the stud to the plate, fusing it into the molten metal to create the extremely strong weld expected from stud welding.
The Role of Ferrules
Ferrules are essential for containing the molten metal pool. Without a ceramic ferrule, the molten metal could spread outward, not leaving enough to fuse the stud onto the plate and also creating a messy finish. The primary purpose of the ceramic is to shield the stud from the air during the welding process, preventing porosity and contaminants from affecting the weld. It can also act as an arc shield to reduce UV exposure in the surrounding area.
The ceramic ferrules are shaped like a ring around the stud and contain the molten pool between the stud and the plate. They shape the weld to create a neat join that is unnoticeable and seamless by containing the molten metal within their shape. Once the process is complete, the ferrule needs to be removed. Because they are ceramic, it’s easy for an operator to chip away the ferrules to leave the finished weld.