How can you select the best welding Electrodes?
Choosing the welding Electrode is a very crucial part of the manufacturing process, especially in the Building Construction and Automotive sectors. These Electrodes’ Classification marks start with E followed by either a four-digit number or a five-digit number for example E6013, E316, E7018, etc.
Every letter of the Electrodes represents some crucial information. For example Electrode E6011 –
E – Electrode
60 – Minimum Tensile Strength ( i.e 60 Ksi )
1 (second last digit) – The position in which the Electrodes should be positioned on the job.
11 – The last two digits collectively show the Polarity and the Flux Composition of the Electrodes.
E 60 1 10
Electrode Tensile Strength Position Type of Coating and Current
After knowing this fundamental information about the Electrodes let’s have a look at the top 5 fundamental factors to be considered while selecting the right Electrode.
- Information about the Base metal.
The mechanical and chemical properties of the Electrodes should be taken into consideration primarily for a sturdy outcome.
- Mechanical properties – The Tensile Strength of the Electrode and the Tensile Strength of the parent metal to be welded should be as close as possible to decrease the chances of cracking of the Electrodes.
- Chemical properties – To check the chemical properties of the Electrode is also an important aspect. Especially, Carbon percentage of the Electrode and the parent metal, both values should match and be as close as possible.
- Thickness of Base Metal – Welding Electrodes with a softer arc and less penetrating power can provide good results, but for thicker materials, we need the Electrodes with digging arcs that can achieve deeper penetration, maximum ductility, and low hydrogen content. To achieve defect-free welding.
- Welding position of Electrode-
The second factor is the welding position of the Electrode. Each Electrode is used for welding at a specific location. Therefore, we need to select the Electrode according to our working position. The welding position is specified by the Electrode Classification itself, that is, the second-to-last digit indicates the position. For example, in the Grade E6013 Welding Electrodes, the second last digit, position 1, indicates All Positions (i.e. Flat, Horizontal, Vertical (up) & Overhead position) which can be used further.
1 – All Positions
2 – Flat, Horizontal
4 – Flat, horizontal, Overhead, Verticle (down)
- Power supply variations on Electrode – Some Electrodes can be used with Alternating Current (AC), while some Electrodes can be used with Direct Current (DC), and some Electrodes can be used for both AC & DC. Therefore, according to the power output of the welding machine, we can choose the Welding Electrodes. For example, if the welding machine can only provide AC output, then we shall not be able to use Electrodes that are not suitable for AC. However, if the welding machine can output both AC and DC, then we can choose from a wider range of welding rods.
DC Electrode Positive (DCEP) or reverse polarity is used when using a Direct Current (DC) power supply, if the Electrode is connected to the Positive Terminal of the machine, and DC Electrode Negative (DCEN) or straight polarity is used if the Electrode is connected to the negative terminal of the machine. Mostly DCEN is the preferred polarity for most shielded metal arc welding.
- Preparation of joints –
Joint preparation is the fourth factor to consider when selecting Electrodes. You can use an Electrode with a digging arc, which can provide deeper penetration. If the installation is tight or there is no slope, for this purpose Electrodes such as E6010 or E6011 can be used. If there is enough root clearance and inclined root face then we can use Electrodes that provide shallow to moderate penetration, such as E6013.
- Finishing welding quality – Before selecting an Electrode, the required quality and welding finish are also important factors to consider. The Welding Electrodes can be selected according to the final processing requirements, such as flat bead, concave bead or convex bead. The weld quality must be suitable for the service requirements of the job.
For an instance, we need to use low-hydrogen Electrodes (such as E7018) to weld low-temperature container parts that should withstand high impact loads under extremely high temperatures and pressures or parts that can withstand corrosive atmospheres. This Electrodes also gives Higher ductility. Therefore, the chance of any welding defects during operation will be minimized.
Thus the very basic information about selecting the best Welding rods for the particular applications which will help you a lot.