Heterogeneous Nano-structure and Its Evolution in Heavily Cold-rolled SUS316LN Stainless Steels

• Watanabe Chihiro

  Division of Mechanical Engineering, Kanazawa University

• Kobayashi Shuhei

  Graduate student, Kanazawa University

• Aoyagi Yoshiteru

  Department of Finemechanics, Tohoku University

• Todaka Yoshikazu

  Department of Mechanical Engineering, Toyohashi University of Technology

• Kobayashi Masakazu

  Department of Mechanical Engineering, Toyohashi University of Technology

• Sugiura Natsuko

  Steel Research Labs., Nippon Steel & Sumitomo Metal Corporation

• Yoshinaga Naoki

  Steel Research Labs., Nippon Steel & Sumitomo Metal Corporation

• Miura Hiromi

  Department of Mechanical Engineering, Toyohashi University of Technology

Bibliographic Information

Other Title

• 冷間強圧延したSUS316LN鋼のヘテロナノ組織とその形成過程
• レイカン キョウアツ ノバシタ SUS316LNコウ ノ ヘテロナノ ソシキ ト ソノ ケイセイ カテイ

Abstract

Evolution of heterogeneous nano-structure in heavily cold-rolled SUS316LN stainless steels was investigated in detail. Transmission electron microscopic observations from the transverse direction (TD) of the 92% rolled specimen revealed the formation of a typical hetero-nano structure composed of ultra-fine lamellae embedded with deformation twin domains. The twin domains had prolate ellipsoidal shape elongated parallel to TD. Two types of twin domains with different crystallographical orientations to matrices could be identified, i.e., i) <211> // rolling direction (RD) and <110> // TD or ii) <110> // RD and <211> // TD, although all the {111} twining planes of both twin domains were oriented nearly parallel to the rolling planes. The ultra-fine lamellae were elongated along <100> direction and nearly parallel to RD. Deformation twins with a few nano-meter spacing were also frequently observed to develop in the lamellae. Evolution sequence of the hetero-nano structure during cold rolling was also investigated. At an early stage of rolling, deformation twins were gradually formed in the whole grains. Then, the regions fragmented grains by twins were further subdivided by a numerous number of shear bands inclined at about 20~45° from the RD, resulting in the formation of “eye-shaped” twin domains surrounded by shear bands and their crystallographical rotation. Cold rolling up to 50% caused a considerable increase in strength and decrease in ductility. While the strength was raised more with increasing reduction up to 92%, both the strength and ductility eventually slightly decreased by further rolling.

Journal

• Tetsu-to-Hagane

  Tetsu-to-Hagane 105 (2), 254-261, 2019

  The Iron and Steel Institute of Japan

Keywords

• heavy cold rolling
• heterogeneous nano-structure
• austenitic stainless steels
• microstructure

Details

• CRID: 1390564238073753472
• NII Article ID: 130007585467
• NII Book ID: AN00151251
• DOI: 10.2355/tetsutohagane.tetsu-2018-075
• ISSN: 18832954
• ISSN: 00211575
• NDL BIB ID: 029495440
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I029495440
• Web Site: https://www.jstage.jst.go.jp/article/tetsutohagane/105/2/105_TETSU-2018-075/_pdf
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed