The principle of the plug test is used to measure the cold crack sensitivity of the low alloy steel heat affected zone.

The experimental principle of the plug: The experimental process is to process the welded steel into a cylindrical pin, and pull the pin out of the corresponding hole in the bottom plate so that the notched end is flush with the outer surface of the bottom plate, according to the selected welding method and severe Controlled process parameters, deposited on the floor a layer of surfacing weld bead, the centerline of the weld pass through the center of the test rod, the penetration depth should be in the coarse-grained region of the heat-affected zone.