What is the significance of using filler material in welding?

Using filler material in welding is essential because it contributes to the necessary properties and strength of the weld joint. Filler materials are often added to the molten pool during the welding process to help create a strong, cohesive bond between the base materials. This is especially important in situations where the base metals have different thicknesses, compositions, or mechanical properties. The filler not only reinforces the joint but also allows for adjustments in composition to meet specific mechanical requirements, such as tensile strength, ductility, and resistance to various forms of stress.

In essence, the filler material plays a crucial role in ensuring that the final welded joint meets the required performance criteria for the intended application, making it integral to the overall integrity and durability of the weld.