Which of the following is an example of an AWS classification aluminum filler rod?

The classification of aluminum filler rods according to the American Welding Society (AWS) follows a specific coding system. The correct example of an AWS classification aluminum filler rod is ER4043. This designation is significant because it specifies both the alloy type and the form, where 'ER' denotes 'electrode and rod' and '4043' refers to a specific aluminum alloy that is commonly used for welding applications.

ER4043 is a versatile filler metal that is primarily used for welding aluminum and its alloys, particularly in automotive, marine, and structural applications. It contains silicon, which improves fluidity and helps to reduce cracking during the welding process. This makes it well-suited for welding applications where good aesthetics and resistance to cracking are necessary.

In contrast, the other options refer to filler metals associated with different materials; for instance, ER308L and ER70S-6 are fillers used for stainless steel and carbon steel, respectively. This distinction highlights the unique properties and applications of different filler metals based on their classifications, making ER4043 the correct choice for an aluminum filler rod.