What does the 'ER' in ER70S-6 stand for in filler rod classification?

The 'ER' in the classification ER70S-6 refers to "Electrode Rod." In the context of filler metal classifications used in welding, specifically for Gas Tungsten Arc Welding (GTAW) and other processes, the "E" denotes that it is an electrode, and the "R" indicates that it can be used as a rod for filler material. The classification helps welders understand the properties and applications of different filler rods, including their suitability for various materials and welding conditions.

In this particular classification, the number '70' signifies the minimum tensile strength of the weld metal produced, which is 70,000 psi, while 'S' indicates that this rod is suitable for use in a flat or horizontal position, and '6' denotes that it has a specific chemical composition and mechanical properties that make it versatile for welding carbon steels. Understanding these elements assists welders in selecting the appropriate filler rods for their projects.