Final answer:
The '1' before the '8' in E7018-1H4R represents the position of the electrode in welding.
Step-by-step explanation:
In the question, the '1' before the '8' represents the position of the electrode. In electrode classification for welding, the first digit indicates the type of current used, and the second and third digits represent the position in which the electrode can be used.
For the E7018-1H4R electrode, the '1' indicates that it can be used for all positions, including vertical, horizontal, and overhead welding.
Example:
E7018-1H4R:
- E: Electrode
- 70: Tensile strength
- 18: Welding position (all positions)
- -1H4R: Flux coating and other additional information