Advertisement

Development of High Strength Austenitic Stainless Steel for Conduit of Nb3Al Conductor

  • H. Nakajima
  • Y. Nunoya
  • M. Nozawa
  • O. Ivano
  • K. Takano
  • T. Ando
  • T. Kawasaki
  • H. Hanawa
  • S. Seki
  • H. Tsuji
  • Y. Sato
  • A. Yamamoto
  • S. Ohkita
Part of the Advances in Cryogenic Engineering Materials book series (ACRE, volume 42)

Abstract

Japan Atomic Energy Research Institute (JAERI) started developing new austenitic stainless steel for a conduit (1–2 mm) of a Nb3Al conductor in collaboration with Nippon Steel Corporation (NSC). A high strength austenitic stainless steel is required for a conduit of a Nb3Al conductor to make the best use of superconducting properties of a Nb3Al conductor. JAERI and NSC successfully developed the high strength austenitic stainless steel, JN1 (YS = 1,300 MPa, KIc = 200 MPavm at 4K) for magnet structures having thick section. However, JN1 is not suitable for a conduit material because elongation of JN1 decreases to less than 10 % due to sensitization during reaction heat treatment for Nb3Al. Therefore, modification of JN1 was performed as a first step to develop a new conduit material which withstands Nb3Al reaction heating. Small trial lots heat-treated at 973 – 1173 K for 2 – 200 hours were prepared and evaluated by Charpy impact test and tensile test at 77 K and 4K. A material having yield strength of 1,390 MPa and elongation of 34 % after aging at 973 K × 200 h are developed up to now. This paper describes requirements on the mechanical properties and status of the development work. In addition, empirical equations to predict 4K yield strength, elongation, and Charpy absorbed energy from 77K data are proposed in this paper.

Keywords

Yield Strength Fracture Toughness Austenitic Stainless Steel High Yield Strength Charpy Impact Test 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    H. Ogata et al. Design of the ITER central solenoid (CS) model coil, to be presented in Proc. of MT-14 (1995).Google Scholar
  2. 2.
    M. Sugimoto et al., Design of the CS insert coil to be presented in Proc. of MT-14 (1995).Google Scholar
  3. 3.
    K. Koizumi et at., Nb3Al insert to be tested in ITER central solenoid model coil, to be presented in Proc. of MT-14 (1995).Google Scholar
  4. 4.
    W. Specking et al., First results of strain effects on lc of Nb3Al cable in conduit fusion superconductors, IEEE Trans. on Applied Superconductivity, Vol. 3, NO. 1 (1993) P. 1342.CrossRefGoogle Scholar
  5. 5.
    A. Bonito-Oliva et al., The potential for SAGBO cracking in a Nb3Sn wind-and-react solenoid using a CICC with Incoloy 908 jacket and glass fabric insulation, to be presented in Proc. of MT-14 (1995).Google Scholar
  6. 6.
    Y. Takahashi et al., Experimental results of the Nb3Sn demo poloidal coil (DPC-EX), Cryogenics. Vol. 31 (1991) p. 640.CrossRefGoogle Scholar
  7. 7.
    M. Shimada et al., Effect of niobium on cryogenic mechanical properties of aged stainless steels, in: “Advances in Cryogenic Engineering Materials,” Vol. 34 (1988) p. 131.Google Scholar
  8. 8.
    H. Nakajima et al., Development of new cryogenic steels for the superconducting magnets of the fusion experimental reactor, ISIJ International, Vol 30 (1990) No. 8, p. 567.CrossRefGoogle Scholar
  9. 9.
    H. Nakajima et al., The Charpy impact test as an evaluation of 4 K fracture toughens, in: “Advances in Cryogenic Engineering Materials,” Vol. 38 (1992) p. 207.Google Scholar

Copyright information

© Springer Science+Business Media New York 1996

Authors and Affiliations

  • H. Nakajima
    • 1
  • Y. Nunoya
    • 1
  • M. Nozawa
    • 1
  • O. Ivano
    • 1
  • K. Takano
    • 1
  • T. Ando
    • 1
  • T. Kawasaki
    • 1
  • H. Hanawa
    • 1
  • S. Seki
    • 1
  • H. Tsuji
    • 1
  • Y. Sato
    • 2
  • A. Yamamoto
    • 2
  • S. Ohkita
    • 2
  1. 1.Japan Atomic Energy Research InstituteNaka, IbarakiJapan
  2. 2.Nippon Steel CorporationFuttsu, ChibaJapan

Personalised recommendations