Formability behavior of friction stir processed dual phase steel

AKTARER S. M., KÜÇÜKÖMEROĞLU T.

METALLURGICAL RESEARCH & TECHNOLOGY, cilt.118, sa.6, 2021 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 118 Sayı: 6
  • Basım Tarihi: 2021
  • Doi Numarası: 10.1051/metal/2021083
  • Dergi Adı: METALLURGICAL RESEARCH & TECHNOLOGY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Applied Science & Technology Source, Compendex, Computer & Applied Sciences, INSPEC
  • Anahtar Kelimeler: friction stir process, formability, Erichsen test, orange peel effect, dual phase steel, MECHANICAL-PROPERTIES, MICROSTRUCTURE EVOLUTION, TWIP STEEL, DEFORMATION
  • Karadeniz Teknik Üniversitesi Adresli: Evet

Özet

This study investigated the formability behavior of dual-phase (DP) steel subjected to friction stir process (FSP), using a miniaturized Erichsen test. The friction stir process yielded a refined microstructure, which consisted of lath martensite and fine ferrite, as a result of dynamic recrystallization (DRX) and phase transformation. Both yield and tensile strength were significantly increased via the grain refinement and increasing martensite fraction. Biaxial formability behavior of the friction stir processed sample exhibited a decline as the Erichsen index (EI) decreased from 2.7 mm to 2.2 mm. However, the required punch load (F-EI) increased compatibly with the strength value after FSP. The grain refinement caused by FSP led to an improvement in the orange peel effect, defined as a negative effect of increased surface roughness after metal forming. The value of mean roughness in the free dome surface of the FSPed sample decreased from 4.90 mu m to 2.62 mu m. It can be concluded that the roughening with the orange peel effect on free surfaces of stretched metal can be eliminated by the friction stir process.