Final answer:
GTAW and PAW are both arc welding processes, but differ in terms of energy source used and the type of materials they are commonly used for.
Step-by-step explanation:
In GTAW (Gas Tungsten Arc Welding), a non-consumable tungsten electrode is used to create an electric arc that melts the base metal and forms a weld. This process is commonly used for welding thin materials and in applications where a high degree of precision is required. On the other hand, in PAW (Plasma Arc Welding), an ionized gas called plasma is used to generate the arc. The plasma arc has higher energy density and can achieve deeper penetration than the GTAW process.
While both GTAW and PAW are arc welding processes, there are some differences between them. One major difference is the energy source used - GTAW utilizes a direct current (DC) power source, whereas PAW can use either DC or alternating current (AC). Additionally, GTAW is generally used for smaller welds and thin materials, while PAW is more suitable for thicker materials and larger welds.
Therefore, the answer to the question is that the energy source used (DC or AC) and the type of materials they are commonly used for (thin or thick) are not common to both GTAW and PAW.