direct current with straight polarity is used
In welding copper alloys with TIG arc welding Direct current with straight polarity is used.
Copper and copper-base alloys have specific properties which make them widely used. Their high electrical conductivity enable their use in the electrical industries, and the corrosion resistance of certain alloys makes them very useful in the process industries.
TIG welding
Gas tungsten arc welding (GTAW), or tungsten/inert-gas (TIG) welding, is a manual welding process that uses a non-consumable electrode made of tungsten, an inert or semi-inert gas mixture, and a separate filler material.
iron oxide and aluminum
Thermit which is used in Thermit welding is a mixture of Iron oxide and aluminium.
all of the above
Advantages of thermit welding is listed below:
The weld formed has high mechanical strength, excellent corrosion resistance as compared with other forms of weld.
It is highly stable to repeated short circuit pulses the electrical resistance remains unchanged over lifetime of the installation
All parts of the weld section are molten at the same time Weld cools almost uniformly
Results in a minimum problem with internal residual stresses.
all of the above
Thermit welding is a welding process that employs molten metal to permanently join the conductors.
The process employs an exothermic reaction of a thermite composition to heat the metal, and requires no external source of heat or current.
Thermit welding is often used in Replacing broken gear teeth and Repairing broken shears and Joining rails, truck frames and locomotive frames etc.