Welding with 7018 has a few requirements which include storage and usage.
7018 electrode is known as a low-hydrogen rod because of the flux coating designation of 8, 5 and 6 are low-hydrogen electrodes too.
The nomenclature of 7018 stands for the following:
Low hydrogen electrodes need to be stored in an oven capable of maintaining 2500 f. After removal from oven, 7018 electrode has 4 hours of a window in which it should be used. The higher the tensile strength the smaller the window of time in which you must use the electrode. (Refer to Table 5.1 AWS D1.1, 2015)
Electrode current requires DC+ for deeper penetration, but is capable of using AC.
EXX18 electrode is classified under the group 4 designation, this is relevant during certain welding certifications.
Electrodes exposed to the atmosphere longer than the determined window, must be rebaked.
Using 7018 electrodes you will be able to produce smooth strong welds with the proper training and practice. This is known as a scratch rod, it is a medium penetrating electrode. The fumes from this electrode must be avoided, always adhere to the SDS and use proper ventilation.