Final answer:
The process of heating copper to 1300 degrees Fahrenheit is known as annealing, which softens the metal and improves ductility.
Step-by-step explanation:
The process of heating copper tubing to a temperature of 1300 degrees Fahrenheit is best described as annealing. Annealing is a heat treatment process used to soften metals, improve their ductility and remove internal stresses. During annealing, the metal is heated to a specific temperature, maintained at that temperature to allow transformation to occur, and then slowly cooled. This is different from quenching, which involves rapid cooling, tempering, aimed at decreasing brittleness after hardening, and hardening, which increases toughness.