Recrystallization in type 304L stainless steel during friction stirring

Development of Microstructure and Crystallographic Texture in a Double-Sided Friction Stir Welded Microalloyed Steel

“…Austenitic stainless steels were among the first to be studied [5][6], and there is now a growing body of literature demonstrating successful welds in ferritic steels, together with the potential for joining dissimilar steels [7][8][9]. Also, the lower heat inputs, producing fewer metallurgical changes in the heataffected zone (HAZ) compared to fusion welding, is regarded as an additional advantage for FSW of steels [10].…”

“…This is most likely because the application of FSW to ferrous alloys, including microalloyed steel, with high melting points has been limited due to the high temperatures and critical wear conditions encountered by the rotating tools. Therefore, most studies have focused on developing appropriate tool materials for FSW of ferrous alloys with ability to resist the aforementioned problems [3,[5][6][7][8][9]11]. Generally, the studies on microstructural evolution during FSW of ferrous metals, having both face-centred cubic (FCC) and body-centred cubic (BCC) crystal structures, are mainly on materials in which solid state phase transformation does not occur during the process.…”

“…FSW has been developed to process steels, which has been achieved through improvements in the tools which are capable of withstanding higher flow stresses at higher temperatures, in the range 1000-1200°C [3,[5][6][7][8][9]. Austenitic stainless steels were among the first to be studied [5][6], and there is now a growing body of literature demonstrating successful welds in ferritic steels, together with the potential for joining dissimilar steels [7][8][9].…”

“…It is claimed that the advantages of FSW include rapid joining speeds, elimination of weld cracking and porosity and no need for shielding gas of filler metal. All lead to improved mechanical and metallurgical weld properties, and normally, a lower residual stress than fusion welding [1][2][3][4][5]. The restriction of welding only lower melting temperature alloys such as aluminium, due to the severe conditions encountered by the rotating tool has over the past decade, to some extent, been overcome, and FSW developed to process some steels.…”

A microtexture investigation of recrystallization during friction stir processing of as-cast NiAl bronze

“…Friction stir processing has been employedt oh omogenize and refine microstructures in both cast and wrought metals, includinga lloys of Al [5][6][7][8][9][10] and Mg [11,12] and higher melting alloys of Cu, [13] Fe, [14] and Ti. [15] BenefitsofFSP in cast metals include elimination of porosity and local conversion of cast microstructures to awrought condition, with enhanced near-surface properties.S ignificantly improved strength/ductilityc ombinations [16,17] and high-strain-rate superplasticity [3][4][5][6][7]18] havebeen achieved by FSP of wrought materials.…”