Assumptions made in design of welded joints?

In the design of welded joints, several key assumptions are typically made, including uniform material properties across the joint and base materials, consistent weld quality and integrity, and that the weld will behave similarly to the base material under load. Additionally, it is often assumed that the heat input during welding does not significantly alter the microstructure or mechanical properties of the surrounding material. Lastly, the effects of residual stresses and distortion due to welding are frequently simplified or approximated in analyses.