weld
v.v. to join two pieces of metal or plastic together by heating them until they melt and fuse. You use this when you need a very strong, permanent connection between parts.
v. to join pieces of metal or plastic by heating the surfaces to the point of melting and pressing them together. Often used metaphorically to describe the uniting of people or ideas into a single whole.
The mechanic needs to weld the broken frame back together.
The technician used a laser to weld the delicate components of the medical device without damaging the surrounding material.
The artist sought to weld industrial scrap metal into a fluid, organic sculpture that challenged the viewer's perception of weight and rigidity.
The verb is transitive and takes a direct object; it can also be used intransitively to describe the process itself.