Suppression of intergranular corrosion by surface grain boundary engineering of 304 austenitic stainless steel using laser peening plus annealing

Shun Tokita, Hiroyuki Kokawa, Shohei Kodama, Yutaka S. Sato, Yuji Sano, Zhuguo Li, Kai Feng, Yixiong Wu

Research output: Contribution to journalArticlepeer-review

Abstract

Grain boundary engineering (GBE) has a high potential to suppress intergranular degradation and improve weld properties. Thermomechanical processing is typically used to optimize grain boundary character distributions (GBCDs) for the GBE of face-centered cubic materials with low stacking fault energy. Pre-straining plus annealing has achieved the optimal GBCD for GBE of austenitic stainless steels. Typically, cold rolling is used for pre-straining, but is not suitable for products with complex shapes. Laser peening can introduce strain locally and flexibly, even on complex parts. Therefore, this study attempted to apply laser peening as a pre-straining method during the thermomechanical processing. Several sets of process parameters during laser peening were selected to introduce suitable pre-strain into the surface of a 304 steel specimen based on previous GBE studies focusing on cold rolling plus annealing. Annealing at 1260 K for 48 h following laser peening led to an optimal GBCD with over 80 % frequency for coincidence site lattice boundaries and disconnected random boundaries. An intergranular corrosion test revealed that the laser-peened and annealed 304 steel with an optimal GBCD exhibits excellent intergranular corrosion resistance, which is far greater than that of an as-received sample and comparable to that of a cold-rolled and annealed sample.

Original languageEnglish
Article number101572
JournalMaterials Today Communications
Volume25
DOIs
Publication statusPublished - 2020 Dec

Keywords

  • Austenitic stainless steel
  • Coincidence site lattice boundary
  • Corrosion
  • EBSD
  • Grain boundary engineering
  • Intergranular
  • Laser peening

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Materials Chemistry

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