Welding Electrode Classification for SMAW

Welding electrodes classification for Shielded Metal Arc Welding (SMAW) by American Welding Society (AWS) is as follows.

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Mild Steel Coated Electrodes

Example Electrode Designation :

E7018-X

E – Indicates that this is an Electrode.

70 – Indicates tensile strength. Measured in thousands of pounds per square inch.

1 – Indicates welding position.

8 – Indicates the coating, penetration, and current type used. (See Classification Table below)

X – Indicates that there are more requirements. (See Additional Requirements below)

WELDING POSITIONS

1 All positions (Flat, Horizontal, Vertical (up), Overhead) 2 Flat, Horizontal 4 Flat, Horizontal, Overhead, Vertical (down)

CLASSIFICATION TABLE

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

ADDITIONAL REQUIREMENTS

Suffix Additional Requirement -1 Increased toughness (impact strength). -M Meets most military requirements – greater toughness, lower moisture content as received after exposure, diffusible hydrogen limits for weld metal. -H4, -H8, -H16 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

LOW ALLOY STEEL COATED ELECTRODES

SUFFIX TABLE

Suffix Steel Alloy Type Suffix Number Description -A1 Carbon-Molybdenum 0.40 – 0.65 Mo -B1 Chromium-Molybdenum 0.40 – 0.65 Cr 0.40 – 0.65 Mo -B2 Chromium-Molybdenum 1.00 – 1.50 Cr 0.40 – 0.65 Mo -B2L Chromium-Molybdenum Lower Carbon B2 -B3 Chromium-Molybdenum 2.00 – 2.50 Cr 0.90 – 1.20 Mo -B3L Chromium-Molybdenum Lower Carbon B3 -B4L Chromium-Molybdenum 1.75 – 2.25 Cr 0.40 – 0.65 Mo -B5 Chromium-Molybdenum 0.40 – 0.60 Cr 1.00 – 1.25 Mo -B6 4.6 – 6.0 Cr 0.45 – 0.65 Mo -B8 8.0 – 10.5 Cr 0.8 – 1.2 Mo -C1 Nickel Steel 2.00 – 2.75 Ni -C1L Nickel Steel Lower Carbon C1 -C2 Nickel Steel 3.00 – 3.75 Ni -C2L Nickel Steel Lower Carbon C2 -C3 Nickel Steel 0.80 – 1.10 Ni -NM Nickel-Molybdenum 0.80 – 1.10 Ni 0.40 – 0.65 Mo -D1 Manganese-Molybdenum 1.00 – 1.75 Mn 0.25 – 0.45 Mo -D2 Manganese-Molybdenum 1.65 – 2.00 Mn 0.25 – 0.45 Mo -D3 Manganese-Molybdenum 1.00 – 1.80 Mn 0.40 – 0.65 Mo -W Weathering Steel Ni, Cr, Mo, Cu -G No required chemistry -M Military grade May have more requirements

CHEMICAL SYMBOLS FOR THE ELEMENTS

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 Cb Columbium Hardness – Improves mechanical properties V Vanadium Hardness – Improves mechanical properties