Classification of welding electrodes consists of a prefix letter “E” specifying an electrode, a group of two or three digits specifying weld metal strength in ksi in the ‘as-weld’ or stress relieved condition, and a final two digits specifying type of covering, weld position and current characteristics.
1. Nomenclature of electrode specification:
E60xx – 60ksi (420MPa) E70xx – 70ksi (490 MPa) E80xx – 80ksi (560 MPa) E90xx – 90ksi (630 MPa) E100xx – 100 ksi (700 MPa)
Exx10 – Cellulosic covering for the use with DC reversed polarity
(E6010) – Deep penetration and all positions electrode for general purpose. Exx11 – Cellulosic covering for AC or DC., all position.
(E6011) – Deep Penetration and thin slag, X-ray quality weld. Exx12 – Rutile covering AC or DC, all positions.
(E6012) – Medium penetration, good choice for fit-up work. Exx13 – Rutile electrode, AC or DC, all position.
(E6013) – Good performance in sheet metal welding.
Exx14 – Iron powder rutile same characteristic as Exx 13, but with a higher welding speed. Exx15 – Basic low hydrogen covering requiring use of DC only, all positions for steel welds. (E7015) – Good for high sulfur steels.
Exx16 – Basic low hydrogen covering as Exx15 but with addition of potassium (E7016) – Salts to allow operation with AC.
Exx18 – Low hydrogen electrode as Exx 16, but with 30% iron powder to give (E7018) Exx20 – Typical mineral (iron oxide/silicate) covering for use in flat and (E6020) Exx24 – Rutile and 50 per cent iron powder covering similar to Exx12, with (E7024)
Exx27 – Mineral plus 50 iron powder covering with similar (E6027) characteristics to Exx20.
Exx28 – Low hydrogen basic plus 50 per cent iron powder covering with high (E7028) deposition rate Exx30 – Mineral covering similar to Exx20 but high deposition rates. F position only.
Note : Typical welding electrodes in brackets are most widely used. The use of mineral or iron oxide/silicate covered electrodes is decreasing in the USA and UK.
Electrodes Designations:
Electrode types: EX XXXX such as, ER 4211:
The first letter “E” indicates a covered electrode for SMAW, manufactured by extrusion process. The
second letter “R” indicates type of covering e.g., R = Rutile, A = Acid, B = Basic, C = Cellulosic, RR
= Rutile heavy coated, S = any other type not mentioned here.
The first numerical “4” indicates strength (UTS = 410-510 MPa) in combination with the yield strength of the weld metal deposit YS = 330 MPa. The second numerical digit indicates percent elongation in combination with the impact value of the weld metal deposited. Thus “2” means 22 per cent minimum elongation with impact 47 J at zero °C.
The third digit “1” shows welding position in which the electrode may be used. 1 = means all positions.
2 = all position except vertical
3 = flat butt weld horizontal/vertical fillet weld 4 = flat butt and fillet weld
5 = vertical down and flat butt
6 = any position not mentioned here.
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References:
1. AQC Inspection
