MFE 201 Lecture Notes - Lecture 41: Electrical Resistance And Conductance, Carbon Steel, Superplastic Forming
31 Mar 2016
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Rely on high pressures to achieve metallurgical bond. Sometimes they are used with heat but not enough to melt. Exception: resistance welding uses pressure but does melt the base metal. Relies on heating the workpiece interface with electric current. Commonly, "spot welding" refers to resistance spot welding. Due to the spot nature of the process, it produces stress concentrations, also it is not watertight. Resistance seam welding produces a series of contiguous welds that form a line weld which is watertight. Geometries are limited to lap and lap modi ed welds. (a) sequence in resistance spot welding. This is one of the most commonly used process in sheet-metal fabrication and in automotive-body assembly. Note that the peak temperature occurs at the interface of the material where the resistance is greatest. Other peaks occur at other interfaces as well. Note that the electrodes are cooled to keep them from softening and deforming.
