AG Mechanics CDE Practice Exam Prep – Practice Test & Study Guide

The molten part of the weld where the heat is being applied is called the puddle. This is the area where the weld filler metal and base material are joined together to form the weld. This is the primary area of heat and fusion, making it the correct answer.

Bead and tack weld are incorrect options because they refer to specific types of welds rather than the molten part of the weld. Flux is also incorrect because it is a material used to clean and prevent oxidation during the welding process, rather than the molten part itself.