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Electrode shape, polarity, and its effects

Electrode shape, polarity, and its effects

Electrodes play a major role in welding operations with their shape and polarity. Usually, electrodes are made of metal or alloy with or without the covering of flux.

Welding electrodes carry the currents for initiating heat which is used for melting both filler material and base metal to obtain an ideal weld joint.

Electrode shape and polarity

A sound weld joint depends on the implementation of a Correct electrode shape and polarity, it decidedly produces better welds.

Polarity has a direct effect on the shape of the welding electrode and the depth of the welding arc. The change of polarity also changes the intensity of the welding arc, which may cause a direct effect on the welding joint, The effects of electrode shape and its polarity can be described as follows:

A.C Polarity

Electrode shape, polarity and its effects

The following factors are effective when welding using AC polarity.

  • The electrode carries more current as compared to both DCRP and DCSP.
  • The arc cleanliness of the base metal is maintained by the use of AC polarity.
  • Penetration is not high with the use of AC polarity, but it remains normal.
  • The heat distribution between the workpiece and the electrode remains the same
  • The tip of the electrode remains comparatively cool when using AC polarity.
  • The average arc voltage in an argon atmosphere is 16 V.

DCRP Polarity

Electrode shape, polarity and its effects

The following factors are affected during welding in DCRP (Direct Current Reverse Polarity)

  • In D.C.R.P. polarity, the welding electrode heats up more because about 66.66% of the heat is generated in the welding electrode and the rest of 33.33% is in the job.
  • In DCRP polarity, the average voltage in the argon atmosphere is 19 volts which are higher than the arc polarity.
  • The chances of melting and damage due to overheating of the electrode are comparatively high, but the cleaning action is better in this method.
  • Normally applied currents are less than 125 amps (up to 6 mm diameter electrode) to avoid overheating

DCSP Polarity

The following factors are affected during welding in DCSP (Direct Current Streight Polarity).

  • In DCSP polarity, the average arc voltage in the argon environment is 12 volts.
  • Deep penetration is achieved in this polarity.
  • 33.33% of heat is generated at the electrodes and 66.66% at the workpiece.
  • Welding currents up to 1000 amps can be employed for 6 mm diameter electrodes.
  • No arc cleaning of base metal
  • electrode runs colder than AC or DCRP, and
  • No arc cleaning of base metal

See more 
Selection of Electrode in the welding process