Microstructural Evolution During a Solid State Tube Pinch Weld of Type 304l Stainless Steel

Abstract Microstructure development is examined for a specialized spot weld that used as solid-state closure process austenitic stainless steel tubing, referred to pinch welding. In order elucidate the microstructural evolution of weld, series test welds were made at nominal conditions using tubing and production like components. These normally terminate after twelve cycles 60 Hz AC process. this study, tubes welded from one microstructure variables each individual cycle number characterized radiography optical metallography. Two electrochemical etchants highlight different features. The study revealed that: (1) type largely complete about six current, half time utilized; (2) resistance, deformation, length approach “steady-state” cycles; (3) both oxalic nitric acid electrolytic are useful highlighting specific attributes 304 L steel. Finally, two distinct regions can be identified these welds: edge which driven by concentrated recrystallization, grain growth, center region, more typical forge welding micro-asperity breakdown followed diffusion grain-growth.