What should be done immediately after the closure weld before applying a pulling force?

The correct procedure after completing a thermite weld involves cooling the welded area to a specific temperature, which is crucial for the integrity of the weld and the adherence of the materials being joined. Cooling to 700° F serves to ensure that the weld does not become brittle and maintains adequate strength and ductility before any pulling forces are applied. This temperature allows the material to stabilize and helps prevent any stress that could lead to cracking or failure of the weld during subsequent operations.

Cooling to room temperature or finishing grinding the weld might result in issues related to early application of force or compromising the surface integrity of the weld, while curing for an hour does not address the necessary temperature management right after welding. Proper cooling to the specified range is critical in maintaining the quality and effectiveness of the weld before any mechanical stress is introduced.