An area next to the heat-affected zone that has suffered some softening and loss of strength.

The microstructure of the weld that has been melted and will therefore have properties more like a casting than the base metal.

An area near the heat-affected zone affected by welding that may experience intergranular corrosion.

The high residual stress zone adjacent to the weld fusion line that will have higher hardness than the weld or base material.