Which two types of gas cups are commonly used in welding?

Ceramic and fused-quartz cups are commonly used in welding because they provide excellent thermal stability and resistance to the high temperatures encountered during the GTAW (Gas Tungsten Arc Welding) process. These materials are capable of withstanding the intense heat generated while welding, making them suitable for tasks that require precision and durability.

Ceramic gas cups help in providing a consistent and stable gas coverage to the weld area, which can enhance the quality of the arc. Fused-quartz cups are particularly valued for their ability to maintain clarity and withstand thermal shocks, thus ensuring consistent shielding gas flow.

The other types of cups, while they may serve specific purposes, do not generally offer the same level of performance in high-temperature environments or with the precision required in welding applications. This is why ceramic and fused-quartz are the preferred materials in this context.