The 7018 welding electrode is very popular for its versatility and flexibility on various types of welding purposes. This rod is always referred to as the “low-hydrogen electrode” with the moisture outer coating that is very useful to create a strong crack-resistant weld. However, the only tricky thing when working with the 7018 is its storage. So, let’s dive right into more details about the 7018 welding rod and other things that you might not know about this rod.
The 7018 or officially “the E7018 welding rod” is a medium-penetration “fill-freeze” electrode designed to weld high-tensile carbon-steel materials.
It is very suitable to use on the metals that are very difficult to be welded as the low-hydrogen flux coating that been coated on the 7018 rods is designed to make the welding process more smoothly and effectively for those hard-to-work metals. The E7018 welding rod is highly regarded especially in structural welding due to its robust weld qualities and is commonly used in the construction of high-rise buildings, bridges, shopping malls, dams, and other highly-strengthened structures. Moreover, E7018 welding rods are easy to use with smooth weld results.
Unlike most “fill-freeze” welding rods that use direct or straight polarity DC current, the E7018 is identified as a reverse polarity DC or DC+ electrode. However, the E7018 possesses a flux coating that is designed to work with AC or alternating current as well. Moreover, the same flux coating often leads to the classification of the E7018 as “low-hydrogen” electrode.
What Do the Numbers Mean on a 7018 Welding Rod?
The E7018 welding rod is one of the several electrode types with AWS designation. The AWS assigns four or five digits after the letter. In this designation system, the first two or three digits indicate the tensile strength of the welded material, which is measured in kpi or kilo-pounds per square inch.
Some electrodes like the E7018 have additional requirements, and these requirements are denoted by a suffix in its designation (i.e., E7018-1). The suffix “-1” indicates increased toughness or ductility; “-M” for military requirements; H4, H8, and H16 are indicative of diffusible hydrogen limits in mL/100 grams (e.g., H8 = 8 mL/100 grams). In addition to these requirements, the suffix can also signify the presence of a particular alloy in a low-alloy steel-coated electrode.
Tips on How To Weld E7018 Welding Rod
Welding with E7018 electrode can be tricky. The E7018 is a very versatile electrode as it deposits a significant amount of materials to create a very strong weld, but it can quickly solidify as well. In order to create an optimum weld, you should follow these guidelines:
7018 Amperage Settings
There is a recommended amperage for every corresponding rod diameter size or for the thickness of steel you plan to weld with the 7018 rods.
You can refer to the rod manufacturer’s manuals for setting up the accurate amps. If, for whatever reason, there is no such recommendation, the prevailing general rule for amperage as listed below.
In general rules of thumb, you can increase current up to 30 amps per 1/32 inch rod diameter. However, the thickness of steel is the additional factor you needed to take into consideration too.
In conclusion, These amperage recommendations may vary from one manufacturer to another. The best practice for identifying the correct amp’s volume is through the observation of the conditions of the welding rod and the results of the welding. Commonly, the maximum currents you can use with the 7018 rods is up to 225 amps.
What If The Current Is Too Low?
If the amp is too low, you will have a tough time to melt the rod and the joint effectively. The rod head will stick to the surface of the welding object occasionally during the welding process. And the molten puddle is that sufficiently penetrate through the metal to form the two metal in one piece.
What If The Current Is Too High?
If the current is too high, the welding “keyhole” during the welding process is too large and easily melt through the metal and leaving a broken hole on the steel. The welding rod will become melting-red up to if you set the current too high.
E7018 Welding Rod Care
It is of utmost importance that the E7018 are appropriately stored in a moisture-free environment as moisture can easily degrade the low-hydrogen flux coating of the electrode. When the low-hydrogen electrode flux absorbs moisture, the resulting arc tends to pop and spit. Moreover, the weld becomes weak and porous. Shielding the E7018 welding rod from moisture can be achieved by using specialized rod ovens. Improvised rod ovens made from defunct, old refrigerators can be used by simply adding a high-wattage lamp inside; but this is not widely recommended.
Welding rods exposed to moisture for a considerable amount of time should be re-baked at around 371℃ to 427℃ (700℉ to 800℉). Moreover, the E7018 welding rods should be handled with care as the flux coating can break-off from the rod. Damage rod tips can produce long electric arcs. However, if the flux is damaged along the length of the flux coating, the welding rod needs to be replaced before the damaged part or should be replaced completely.