- Alloy Steel Electrode Classification Sheet
- Alloy Steel Electrode Classification Scale
- Welding Electrode Classification Numbers
RATNA 7015-A1 (AWS A5.5: E 7015 A1)Low Alloy Electrode for Low Temperature services CLASSIFICATION: AWS/SFA-5.5: E 7015 A1 APPROVAL: CHARACTERISTICS: A Basic coated, iron powder, Low hydrogen electrode producing 0.50% Mo weld deposit. Welding electrodes classification for Shielded Metal Arc Welding (SMAW) by American Welding Society (AWS) is as follows. Tags: #PipingEngineering #Welding #SMAW #WeldingElectrode 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.
GMAW (MIG welding) electrodes are designated by some letters and numbers such as ER70S-6, ER90S-6 and E308L etc. I will explain the meaning of these symbols:
FOR CARBON STEEL OR MILD STEEL (SUCH AS ER70S-6 OR ER70S-3)
Where,
ER – Designates electrode or filler rod
XX – Designates the minimum tensile strength of the deposited weld metal
S – Stands for solid wire
Y – Designates the chemical composition of the additives such as deoxidizing agent or cleansing agent used on the electrode, it may affect the polarity setting also.
FOR EXAMPLE:
ER70S-6
Where,
ER – Designates a welding electrode or filler wire
70 – Designates the minimum tensile strength of the deposited weld metal shall be 70 Ksi or 70,000 Psi
S – Stands for solid wire
6 – Reflects the amount of oxidizing agent and cleansing agent on the electrode. In particular the number 6 means that more deoxidizers have been added to the wire, which is helpful when welding on dirty or rusty steel.
FOR STAINLESS STEEL
Stainless steel electrodes are designated in a slight different way. Some of the commonly used stainless steel electrodes are ER308L and ER309L etc. Meaning of these symbols is explained below;
ER308L
Where;
ER – Stands for electrode or filler wire
308 – Designates the grade of stainless steel of the electrode or filler wire
L – Designates that it is a low carbon electrode
FOR ALUMINIUM
For Aluminum, electrodes are designated as ER4043, ER5350 etc. These electrodes are designated in a different way. For example;
ER4043
Where,
ER – Stands for electrode or filler wire
4 – Designates series of Aluminum of which the electrode is made from. In this case it’s a 4000 series Aluminum
043 – Reflects the amount of silicone added to the electrode
SHIELDING GAS:
GMAW requires a shielding gas, to protect the weld pool from atmospheric contamination. Following gases are used as shielding gas;
- Argon
- Carbon Dioxide
- Helium
(NOTE: Whenever Carbon dioxide is used as shielding gas in Gas Metal Arc Welding (GMAW). The term MAG (Metal Actve Gas) welding is used, because Carbon dioxide is an active gas. Whereas, other shielding gases such as Argon and Helium are inert in nature. Hence, whenever theses gases are used as shielding gas, the term MIG (Metal Inert Gas) welding is used.)
These gases are used alone or a combination of gases can also be used. Commonly used combinations of inert gases are;
- 75% Argon + 25% Carbon Dioxide (most popular combination)
- 98% Argon + 2% Carbon Dioxide
Argon helps in achieving cleaner weld whereas, Carbon dioxide helps in getting a deeper penetration. Carbon dioxide can be used alone also and it is effective while welding thinner metals.
Relationship between filler wire diameter, current range and wire feed speed:
Alloy Steel Electrode Classification Sheet
In MIG/MAG welding, Voltage, Current and wire feed speed must be controlled for sound welding
The Voltage controls the weld profile. Whereas, the Current controls the heat input, size of weld and the depth of penetration.
The following table (Table – 1) gives the current range and the filler wire feed speed, based on the filler wire diameter. This table is just a guide and the ranges may vary depending upon the shielding gas and parent metal.
Table – 1
| S.No. | Diameter (mm) | Current Range (A) | Wire feed speed (m/min) |
| 1 | 0.6 | 40 – 100 | 2 – 5 |
| 2 | 0.8 | 40 – 150 | 3 – 6 |
| 3 | 1.0 | 100 – 280 | 3 – 12 |
| 4 | 1.2 | 120 – 350 | 4 – 18 |
Each manufacturer has its own compounds for the coverings. Therefore, electrodes from different manufacturers may not have exactly the same tensile strengths, even though the classification numbers are identical. The classification number indicates the minimum tensile strength the filler metal may have. The letter E preceding the four or five digit number (EXXXX) indicates a welding electrode used in arc welding. See Figure 5-45.
The meaning of the digits in the AWS classification number is as follows. The first two or three digits of the four or five digit number (E60XX or E100XX) represent the tensile strength. That is, 60 means 60,000 psi (414MPa) and 100 means 100,000 psi (689MPa). The value 60,000 psi (pounds per square inch) may also be shown as 60 ksi. The letter “k” represents 1000 lbs (a “kilopound”), so 60 ksi (kilopounds per square inch) is the same as 60,000 psi (pounds per square inch). The tensile strength may be given in the “as-welded” or the “stress-relieved” condition. See the electrode manufacturer's specification to determine under what condition the indicated tensile strength occurs. “As-welded” means without post heating. “Stress-relieved” means the weld has been given a heat treatment after welding to relieve stress caused by the welding process. See Chapter 29 for an explanation of stress caused by welding.
The second digit from the right indicates the recommended position of the joint that the electrode is designed to weld. For example, an EXX1X electrode will weld in all positions whereas EXX2X electrodes are used for welds in the flat or horizontal welding position only. An EXX4X electrode is recommended for flat, horizontal, overhead, and vertical downhill welding.
The right-hand digit indicates the power supply (ac, DCEN, or DCEP), the type of covering, and the presence of iron powder or low-hydrogen characteristic (or both).
The last two digits need to be looked at together. The two digits give the welder information on the electrode covering, current to use, and position to use the electrode. See Figures 5-44 and 5-45, which show the type of electrode covering, position the electrode is designed for, and the type of current to use for various carbon and low-alloy steel electrodes.
Occasionally an electrode number may have a letter and number after the normal four or five digits, such as E7010-A1 or E8016-B2. The letter and number combination or suffix is used with low-alloy steel electrodes. The suffix indicates the chemical composition of the deposited weld metal. See Figure 5-46. The letter A indicates a carbon-molybdenum steel electrode. The letter B stands for a chromium-molybdenum steel electrode. The letter C is a nickel steel electrode, and the letter D, a manganese-molybdenum steel electrode. The final digit in the suffix indicates the chemical composition under one of these broad chemical classifications. The exact chemical composition may be obtained from the electrode manufacturer.
The letter G is used for all other low-alloy electrodes with minimum values of molybdenum (0.20% minimum); chromium (0.30% minimum); manganese (1% minimum); silicon (0.80% minimum); nickel (0.50% minimum); and vanadium (0.10% minimum) specified. Only one of these elements is required to meet the alloy requirements of the G classification.
An example of a complete electrode classification is E8016-B2:
- E—Indicates electrode.
- 80—Indicates tensile strength (80,000 psi or 80 ksi).
- 16—Indicates a low-hydrogen, potassium covering used with ac or DCEP (reverse polarity). DCEP means direct current electrode positive.
- 1—Indicates it is an all-position electrode.
- B2—Indicates that the deposited metal chemical composition is a low-alloy chromium-molybdenum steel with 1.25% chromium and 0.50% molybdenum.
Alloy Steel Electrode Classification Scale
Manufacturers imprint AWS numbers on the covering material near the grip end for identification. Figure 5-47 shows how shielded metal arc welding electrodes are marked with AWS numbers.Welding Electrode Classification Numbers