Which two metal transfer methods are limited to flat and horizontal welding positions?

In MIG welding, different metal transfer methods have specific characteristics that influence their application in various positions. The correct choice highlights that globular and spray transfer methods are primarily suited for flat and horizontal positions.

Globular transfer involves the formation of large metal drops that fall under the influence of gravity. This transfer can be less stable and tends to produce significant spatter, which warrants control over the welding conditions. It is generally used in situations where the weld pool is less likely to be affected by gravity, making it suitable for flat and horizontal positions.

Spray transfer, on the other hand, involves a fine stream of molten metal droplets propelled from the electrode. This method provides a very stable arc and a clean weld with minimal spatter. However, it requires a higher voltage and is primarily effective at flat or slightly inclined positions, as the force of the weld pool could struggle against gravity in vertical or overhead positions.

The other methods listed in the options have different characteristics and applications. For example, pulsed spray transfer can be advantageous for various positions due to its control over heat input and deposition rate. In contrast, short circuit transfer is known to be versatile, but its limitation arises from its efficacy in varying positions, including vertical and overhead, especially in thin materials.