Final answer:
When metal work pieces are welded while laying flat and parallel to the bench or shop floor, this is known as flat welding.
Step-by-step explanation:
Welding is the process of joining metal work pieces by melting them with solder and heat. The technique can vary depending on the position of the work pieces in relation to the welder. When the work pieces are laid out flat and parallel to the bench or shop floor, this position is referred to as flat welding. It is commonly used because it allows the welder to work on the pieces in a stable and easily accessible manner.