Welding Electrode Classifications

Mild Steel Coated Electrodes

E	Indicates that this is an electrode
70	Indicates how strong this electrode is when welded. Measured in thousands of pounds per square inch.
1	Indicates in what welding positions it can be used
8	Indicates the coating, penetration, and current type used (see the classification table below)
X	Indicates that there are more requirements. (See Additional Requirements below)

1 Flat, Horizontal, Vertical (up), Overhead

2 Flat, Horizontal

4 Flat, Horizontal, Overhead, Vertical (down)

Flat Position - usually groove welds, fillet welds only if welded like a "V"

Horizontal - Fillet welds, welds on walls (travel is from side to side).

Vertical - welds on walls (travel is either up or down).

Overhead - weld that needs to be done upside down.

E	Indicates that this is an electrode
70	Indicates how strong this electrode is when welded. Measured in thousands of pounds per square inch.
1	Indicates in what welding positions it can be used
8	Indicates the coating, penetration, and current type used (see the classification table below)
X	Indicates that there are more requirements. (See Additional Requirements below)

Same as for Mild Steel Coated Electrodes

Class	Electrode Coating	Penetration	Current Type
Exxx0	Cellulose, Sodium	Deep	AC, DCEP
Exxx1	Cellulose, Potassium	Deep	AC, DCEN
Exxx2	Rutile, Sodium	Medium	AC, DCEP, DCEN
Exxx3	Rutile, Potassium	Light	DCEP, DCEN
Exxx4	Rutile, Iron, Powder, Medium	AC
Exxx5	Low Hydrogen, Sodium, Medium	DCEP	DCEP
Exxx6	Low Hydrogen, Potassium, Medium	AC	AC, DCEN
Exxx7	Iron Powder, Iron, Oxide	Medium	AC, DCEP
Exxx8	Low Hydrogen, Iron, Powder	Medium	AC, DCEP, DCEN
Exxx9	Iron Oxide, Rutile, Potassium	Medium

-1	Increased toughness (impact strength) for E7018 electrodes. Also increased ductility in E7024 electrodes
-M	Meets most military requirements - greater toughness, lower moisture content as received after exposure, diffusible hydrogen limits for weld metal.
-H4	Indicates the maximum diffusible hydrogen limit measured in millimeters per 100 grams (mL/100g). The 4, 8, and 16 indicates what the limit is. Example: -H4 = 4mL per 100 grams
-H8	Indicates the maximum diffusible hydrogen limit measured in millimeters per 100 grams (mL/100g)
-H16	The 4, 8, and 16 indicates what the limit is. Example: -H4 = 4mL per 100 grams

C	Carbon	Most effective hardening element in steel
Mn	Manganese	Hardening element second to carbon
Si	Silicon	Deoxidizer, moderate strengthener
P	Phosphorus	Causes cracking if too high
S	Sulfur	Aids in machining - Cracking problems like P
Cr	Chromium	Hardness (low) - corrosion resistance (high)
Ni	Nickel	Hardening element - better cold toughness
Mo	Molybdenum	Hardenability - high temp tensile - creep strength
B	Boron	Very small amounts increase hardness
Cu	Copper	Corrosion resistance (low) - cracking (high)
Al	Aluminum	Deoxidizer - improves mechanical properties
Ti	Titanium	Removes: Oxygen, S, N, and C
N	Nitrogen	Improves strength - lowers toughness
Nb	Niobium	Hardness - Improves mechanical properties (formerly Columbium [Cb])
V	Vanadium	Hardness - Improves mechanical properties