Final answer:
The correct option is C) Fusion and pressure welding. Welding processes are mainly divided into fusion welding, where metal pieces are melted and fused together, and pressure welding, where metals are joined using mechanical pressure without melting. These processes are key in metal fabrication and construction.
Step-by-step explanation:
Welding processes are a critical aspect of modern engineering, and they can be mainly classified into two categories: fusion welding and pressure welding. Fusion welding involves heating two or more pieces of metal to their melting point and joining them, allowing the same kinds of metal to coalesce into a single piece as they cool. Examples of fusion welding include arc welding, gas welding, and the thermite reaction, where a reaction generates sufficient heat to melt iron. On the other hand, pressure welding employs mechanical pressure to join metals at a temperature below their melting points; an example is forge welding, a process used for thousands of years by blacksmiths.
Both welding processes play a pivotal role in the fabrication and construction of metal structures and components. They are chosen based on the materials involved, the desired strength and characteristics of the weld, and the application for which the weld is being made. Each weld type has its unique benefits and is suitable for different scenarios in the broad field of metalworking and construction.