Spot Welding

Questions and Answers

Class 20 material is a designation of the Resistance Welding Manufacturers Alliance (RWMA).  It describes a copper base material with high conductivity and good strength, similar to Class 2.  In addition it has better resistance to annealing and may have less tendency to stick to the work piece.  Class 20 is most often used to weld galvanized materials.

Class 3 material is a designation of the Resistannce Welding Manufacturers Alliance (RWMA).  It describes a group of copper alloys with excellent strength and good electrical conductibity.  Class 3 is often used to weld stainless steel, nickel alloys and other highly resistive - strong materials that require high weld forces.

bar stock

Class 3 Bar Stock

Class 2 material is a designation of the Resistance Welding Manufacturers Alliance (RWMA).  This is a group of copper alloys with high strength and electrical conductivity.  Class 2 is the most used material in the resistance welding industry.  As electrodes it is used for welding bare and coated steels.

bar stock

Class 2 Bar Stock

Class 1 material is a designation of the Resistance Welding Manufacturers Alliance (RWMA) which describes a group of copper alloys with good strength and high electrical conductivity.  Class 1 is often used to weld aluminum and other good conductors like brasses and bronzes which require high weld currents.

bar stock

Class 1 Bar Stock

There are six standard faces designs.  Shown below are female caps.  The same face designs are offered in male caps and full size electrodes.

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     A-Pointed            B-Dome           C-Flat                   D-Offset             E-Truncated       F-Radiuis

 

The proper choice of electrode face design will depend upon your application, the material being welded and resistance welding process. If Spot welding, you might use any of the six standard designs. The “A”, “B”, “D” and “E” faced electrodes all have the same weld face if purchased in the same body size. The “C” is a flat faced electrode and the “F” is a full large radius electrode which almost appears flat.

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