What characteristic is unique to the abrasive process of SMAW?

The unique characteristic of the abrasive process in Shielded Metal Arc Welding (SMAW) is that it generates heat through an electric arc. This is the fundamental principle behind SMAW, where an electric current is passed between a coated electrode and the base metal. The arc created by the electrical discharge generates sufficient heat to melt both the electrode and the workpiece, allowing for the creation of a strong welded joint.

This process differentiates SMAW from other welding techniques that do not rely on an electric arc for heat generation. The electric arc can reach high temperatures, which is crucial for melting the metals being welded. The other options either do not accurately describe the SMAW process or relate to different welding techniques. For instance, water cooling is more associated with some other processes that require temperature control, while the notion of operating at low temperatures does not align with the high-heat nature of arc welding. Manual application is indeed a part of SMAW, but it is not exclusive to this process, as other welding methods can also involve manual control.