Crossword Clue:

to join together with heat

AnswerCrossword Clue
FUSEJoin with heat
WELDJoin with heat
OPTEDChose to join, with "in"
ROPEDCoerced to join, with "in"
ANNEALTreat with heat to toughen
LIAISEConnect so as to work together (with)