AWS A5.7 ERCu

ERCu

ERCu filler metals are made of deoxidized copper, but also may contain one or more of the following elements: phosphorus, silicon, tin, manganese, and silver. Phosphorus and silicon are added primarily as deoxidizers. The other elements add either to the ease of welding or to the properties of the final weldment. ERCu filler metals generally are used for the welding of deoxidized and electrolytic tough pitch copper. Reactions with hydrogen in oxygen-free copper, and the segregation of copper dioxide in tough pitch copper may detract from joint efficiency. ERCu welding electrode and rods may be used to weld these base metals when the highest quality is not required.

Preheating is desirable on most work; on thick base metal it is essential. Preheat temperatures of 400°F to 1000°F (205 to 540°C) are suitable.

For thick base metals, gas metal arc welding is preferred. Conventional joint designs consistent with good welding practice are generally satisfactory. An external source of preheating generally is not needed when welding base metal thicker than 1/4 in. (6.4 mm) if high-quality welds are to be obtained.