What is the primary type of current used in gas metal arc welding?

The primary type of current used in gas metal arc welding (GMAW), also known as metal inert gas (MIG) welding, is direct current. This type of current provides a stable and consistent arc, which is crucial for producing high-quality welds. Direct current allows for better control over the welding process, enhancing penetration into the base metal and improving the overall arc stability.

In GMAW, using direct current enhances the efficiency of the welding process, allowing the welder to achieve controlled heat input, reducing spatter, and providing a clean weld appearance. The ability to manipulate the weld bead shape and size is notably easier when using direct current as opposed to alternating current, which can result in varying arc characteristics and may lead to less consistent weld quality.

While other types of current exist, such as alternating current, which is more suitable for certain applications like aluminum welding or specific tasks in tig welding, they do not provide the same benefits as direct current does in gas metal arc welding.