Welding: the main types of electrodes
The electrode is a metal part responsible for approaching the electric current near the welding area to create the electric arc.
The welding electrode should not be confused with the welding rods which are filler metal and not a device intended to transport the electric current.
According to the welding process,
the welding electrode is:
- either fuse, when it melts as the welding progresses, possibly constituting the filler metal and the slag (coated with MMA);
- is non-fusible when it does not melt during welding, but then requires the use of a filler metal and possibly a protective gas
The electrode for welding to the coated electrode
Description
The coated electrode consists of a metal rod called "core" which is covered with a coating.
The core ensures the formation of the arc and the addition of metal while the coating ensures the protection of the weld pool while giving the weld bead a beautiful appearance and additional mechanical properties.
Characteristics
- The diameter of the coated electrode is expressed in mm. Depending on the diameter of the electrode, the welding current intensity must be higher or lower.
Average welding intensity for the flat position
Thickness
- 1.6 mm
- 2 mm
- 2.5 mm
- 3.2 mm
- 4 mm
- 5 mm
3 mm
60 A
70 A
90 A
4 mm
80 A
100 A
120 A
5 mm
90 A
110 A
130 A
160 A
6 mm
90 A
120 A
140 A
160 A
8 mm
90 A
125 A
150 A
170 A
10 mm
130 A
160 A
190 A
- The thickness of the coating influences the shape of the weld bead.
- The type of coating according to the chemical nature of the substances constituting the coating:
- cellulosic coating,
- rutile coating,
- basic coating,
- acid coating.
- Possible welding position
- The welding current to be produced to use the electrode:
- continuous or alternative,
- direct or reverse polarity,
- current intensity.
Symbol
Direct current, recommended polarity
Alternating current, nominal no-load voltage (V)
0
+
0
1
Unspecified
50
2
-
50
3
+
50
4
Unspecified
70
5
-
70
6
+
70
7
Unspecified
90
8
-
90
9
+
90
The symbol 0 is reserved for electrodes used only in direct current.
The main characteristics of the coated electrodes are indicated by an acronym of type E 43 3/2 R 10.
(E = generic symbol, 43 = tensile strength, 3/2 = elongation of the metal and temperature of the point of impact).
But above all R 10 which means:
- R = Coating (rutile for R).
- 1 = welding position (all positions for 1).
- 0 = current (continuous and reverse polarity for 0: electrode connected to the + pole).
The electrode for TIG
Characteristics
The electrodes used in TIG welding:
- Pure tungsten (green tip) used for aluminum alloys.
- Tungsten + zirconium oxide (yellow tip) used for aluminum alloys.
- Thoriated tungsten (red tip) used for steels and stainless steels.
- Cerium-tungsten cerium or lanthanum (gray tip) is increasingly replacing thoriated tungsten.
Sharpening
The sharpening of the electrodes is an important parameter since the quality of the weld bead depends largely on this operation. Depending on whether the welding current is direct current or alternating current, the tip of the electrode will be sharpened differently.
In all cases the streaks due to sharpening grinding must be in the direction of the electrode and must respect an angle of 30 ° to 60 ° with a flat to avoid inclusions of tungsten in the weld bead:
- For welding steels (More info: https://weldinginfocenter.com/best-flux-core-welder/ ) and stainless steel, sharpen from 30 ° to 60 °.
- For welding light alloys and aluminum., Sharpen at 90 °
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