Controls & Transformers

Questions and Answers

Aluminum welds have a narrow plastic range and a very high thermal expansion and contraction. This combination may be the cause for voids in the resultant weld nugget. Application of an increased secondary force near the end of the weld cycle is commonly used to forge the part in its plastic state and close these voids.

Force is used for two main reasons. One is to contain the weld nugget and prevent expulsion and the other is to strengthen the weld by forging the solidifying weld nugget. It is easy to see that if welding force is changed these actions will be affected to some degree. Expulsion could increase or decrease and the resultant weld strength could also increase or decrease.

Group C material is a designation of the Resistance Welding Manufacturers Alliance (RWMA).  It describes a group of Specialty materials with high strength and high electrical conductivity. Their properties make them excellent materials to use in the resistance welding industry as electrodes especially for galvanized steel.

Group B materials is a designation of the Resistance Welding Manufacturers Alliance (RWMA).  It describes a group of Tungsten/Copper materials with high strength and good electrical conductivity.  Their main feature is high strength at high temperatures.  Their properties make them excellent materials to use in the resistance welding industry as electrodes at high heat and forces.

Group A material is a designation of the Resistance Welding Manufacturers Alliance (RWMA).  It describes a group of copper alloys with high strength and high electrical conductivity.  Their properties make them excellent materials to use in the resistance welding industry as electrodes and current carrying componenets used in the machinery of the resistance welding industry.

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