Definition - What does Gusset Plate mean?
A gusset plate is a thin metal object, typically made of steel, that is used to affix independent members of a structure to each other or to a beam to aid alignment.
Gusset plates are used in joint, bend or otherwise disjointed structural locations that require additional support to withstand stresses. They typically occur as flat dish-like triangular or rectangular units and are fastened to beams with the use of bolts or welds.
Corrosionpedia explains Gusset Plate
Gusset plates are prone to crevice and pitting corrosion if used on a structure made of an incompatible base metal that causes it to passivate. When dust or other granular substances are deposited on surfaces, they create an environment where water can accumulate and promote electrochemical reactions that cause corrosion. This can occur between two metals or between a metal and a nonmetal. It causes damage, corrosion and rust formation to the metallic part.