Welding electrodes Classification & baking

This document Describes
1.Welding electrodes Classification
2.baking

1. Welding
Electrodes
Classification
&Baking

2. What is a WeldingElectrode ??
An electrode is a coated metal wire. It is made of materials similar to the metal being welded. For starters, there
are consumable and non-consumable electrodes. In shield metal arc welding (SMAW) also known as stick, electrodes are
consumable, which means that the electrode is consumed during its use and melts with the weld. In Tungsten Inert Gas
welding (TIG) electrodes are non-consumable, so they don’t melt and become part of the weld. With Gas Metal Arc Welding
(GMAW) or MIG welding, electrodes are continuously fed wire. Flux-cored arc welding requires a continuously fed
consumable tubular electrode containing a flux.
How to choose welding electrodes?
Choosing an electrode is determined by the requirements of the welding job. These include:
•Tensile strength
•Ductility
•Corrosion resistance
•Base metal
•Weld position
•Polarity
•Current

3. What do the numbers and letters mean on welding rods?
The “E” indicates an arc welding electrode. The first two digits of a 4-digit number and the first three digits of a 5-digit
number stand for tensile strength. For example, E6010 means 60,000 pounds per square inch (PSI) tensile strength
and E10018 means 100,000 psi tensile strength. The next to last digit indicates position. So, “1” stands for an all
position electrode, “2” for a flat and horizontal electrode, and “4” for a flat, horizontal, vertical down and overhead
electrode. The last two digits specify the type of coating and the welding current.
E 60 1 10
Electrode Tensile Strength Position Type of Coating & Current
Digit Type of Coating Welding Current
0 High cellulose sodium DC+
1 High cellulose potassium AC, DC+ or DC-
2 High titaniasodium AC, DC-
3 High titania potassium AC, DC+
4 Iron powder, titania AC, DC+ or DC-
5 Low hydrogen sodium DC+
6 Low hydrogen potassium AC, DC+
7 High iron oxide, potassium powder AC, DC+ or DC-
8 Low hydrogen potassium, iron powderAC, DC+ or DC

4. Classification of welding rods
1.Basic Electrodes
2.CellulosicElectrodes
3.RutileElectrodes
4.HeavyRutile/HighIronPowder
1.BASICELECTRODES
•Basic electrodes have its last digit should be 5,6,7,8 (Example: 7018)
•Itiscapable of welding All positions.(Flat,horizontal,vertical,overhead)
•Itislowhydrogenelectrodes, Hydrogen occurred only 5 ml/100 gm of weld metal
•Itprovides high quality, Higher strength, good & mechanical properties.
•Baking&drying needed.
•The coating is low-hydrogen iron powder, TiO2, CaCO3, and CaF2(calcium fluoride).
•Basic electrodes such as E7018 are used for critical welds in structural steel construction, bridges, ships, and
offshore oil and gas applications where mechanical properties are important.
•Basic electrodes offer an arc with medium penetration and excellent mechanical properties.

5. 2.CELLULOSIC ELECTRODES
•Cellulosic electrodes have its last digit should be 0,1 (Example: 6010)
•The coating on a cellulosic electrode contains up to 30 percent or more wood flour.
•Cellulosic electrodes include E6010, E7010, and E6011, which are typically used for pipe, barges, farm repairs,
maintenance work, and dirty plate.
•Higher Penetration & Higher travelling speed.
•MainlyusedtoweldinginVerticaldownposition(StovePipeWelding)
•It is higher hydrogen electrodes, Hydrogen occurred only 80-90 ml/100 gm of weld metal
•It provides poor quality.
•Baking & drying not required
•It is capable of welding All positions.(Flat,horizontal,vertical,overhead)
•Cellulosic electrodes provide a digging/driving arc with deep penetration
•The weld puddle wets and spreads well, demonstrates excellent mechanical properties, and has distinctive
ripples.

6. 3. RUTILE ELECTRODES
•Rutile electrodes have its last digit should be 2,3,4 (Example: 6013)
•Rutile is a mineral composed primarily of titanium dioxide.
•Rutile electrodes such as E6013, E7014, and XXX-16 class stainless steel electrodes offer a soft arc with lighter
penetration than cellulosic electrodes.
•The slag is easily controlled, and the arc ignites and restrikes easily, offering greater welder appeal.
•Hydrogen occurred only 25-30 ml/100 gm of weld metal
•It provides low strength.
•Only Drying required.
•It is capable of welding All positions.(Flat,horizontal,vertical,overhead)
•They typically are used in general fabrication applications where mechanical properties for critical weldments
are not required.

7. 3. HEAVY RUTILE/HIGH IRON POWDER
•E7024 is a high iron powder electrode
•Mostlyused in flat horizontal, fillet welds
•Not goodforallpositions
•Only Drying required.
•HighRecoveryelectrodes

9. BAKING OF ELECTRODES
Electrodes exposed to the atmosphere for periods greater than those allowed in Table 5.1 shall be baked as follows:
•All electrodes having low-hydrogen coverings conforming to AWS A5.1 shall be baked for at least two
hours between 500°F and 800°F [260°C and 430°C], or
•All electrodes having low-hydrogen coverings conforming to AWS A5.5 shall be baked for at least one hour at temperatures
between 700°F and 800°F [370°C and 430°C].
•All electrodes shall be placed in a suitable oven at a temperature not exceeding one half the final baking temperature for
a minimum of one half hour prior to increasing the oven temperature to the final baking temperature. Final baking time
shall start after the oven reaches final baking temperature.
Low-Hydrogen Electrode Restrictions for ASTM A514 or A517 Steels.
When used for welding ASTM A514 or A517 steels, low-hydrogen electrodes shall meet the following requirements, as
applicable:
(1)WhenweldingwithE90XX-Xorhighertensilestrengthelectrodes,theelectrodemaybeusedwithoutbaking,providedthe
electrodeisfurnishedinhermeticallysealedcontainers.
(2) When welding with E90XX-X or higher tensile strength electrodes not furnished in hermetically sealed containers, or when

10. welding with E80XX-X or lower tensile strength electrodes whether furnished in hermetically sealed containers or otherwise,
the electrodes shall be baked for a minimum of one hour at temperatures between 700°F and 800°F [370°C and 430°C]
before being used
(3) When welding with E7018M electrodes, or electrodes with the optional H4R designator, the electrode may be used
without baking.