What is the expected result of applying both pressure and electric current in the weld zone during resistance welding?

Applying both pressure and electric current in the weld zone during resistance welding enhances the fusion of the metals being joined. In this process, the electric current generates heat at the contact surfaces due to the resistance of the materials. Simultaneously, the application of pressure helps to promote the intimate contact between the two metal surfaces, facilitating better heat transfer and thus achieving a higher temperature required for welding. This combination of heat and pressure is vital as it encourages the melting of the metal at the interface, leading to a solid weld joint as the molten metal cools down.

Improved fusion is critical for achieving strong and durable welds, as it ensures that the base metals intermingle at a molecular level. This results in a weld that can withstand the stresses and strains it may encounter in service. In contrast, diminished dimensional accuracy, increased corrosion resistance, or reduced residual stress in the weld does not directly result from the principles of resistance welding in the same manner as improved fusion does.