How do weld overlays differ from standard GMAW welding?

Weld overlays are specifically designed to enhance the functional properties of base materials, particularly to improve characteristics like wear resistance, corrosion resistance, and other protective features. This process involves depositing a layer of material on the surface of a component to create a protective barrier without altering the fundamental structure of the underlying metal.

In contrast to standard GMAW, which primarily focuses on joining two base materials together to form a weld joint, weld overlays are not primarily intended for structural bonding but rather for improving surface performance. This distinction makes option B the most accurate description of what differentiates weld overlays from standard GMAW welding.

The other choices do not accurately reflect the purpose and application of weld overlays. For example, stating that they are only for decorative purposes undermines their function as a means to improve durability and performance. Suggesting that they only apply to thin materials overlooks their application across a wide range of thicknesses and types. Lastly, the assertion that weld overlays do not involve any additional materials is incorrect, as they typically require specific overlay materials to achieve the desired enhancements.