Journal of Materials Engineering and Performance

, Volume 12, Issue 6, pp 609–622 | Cite as

Optimization of process parameters for the manufacturing of rocket casings: A study using processing maps

  • G. S. Avadhani
Applications Of Processing Maps

Abstract

Maraging steels possess ultrahigh strength combined with ductility and toughness and could be easily fabricated and heat-treated. Bulk metalworking of maraging steels is an important step in the component manufacture. To optimize the hot-working parameters (temperature and strain rate) for the ring rolling process of maraging steel used for the manufacture of rocket casings, a systematic study was conducted to characterize the hot working behavior by developing processing maps for γ-iron and an indigenous 250 grade maraging steel. The hot deformation behavior of binary alloys of iron with Ni, Co, and Mo, which are major constituents of maraging steel, is also studied. Results from the investigation suggest that all the materials tested exhibit a domain of dynamic recrystallization (DRX). From the instability maps, it was revealed that strain rates above 10 s−1 are not suitable for hot working of these materials. An important result from the stress-strain behavior is that while Co strengthens γ-iron, Ni and Mo cause flow softening. Temperatures around 1125 °C and strain rate range between 0.001 and 0.1 s−1 are suitable for the hot working of maraging steel in the DRX domain. Also, higher strain rates may be used in the meta-dynamic recrystallization domain above 1075 °C for high strain rate applications such as ring rolling. The microstructural mechanisms identified from the processing maps along with grain size analyses and hot ductility measurements could be used to design hot-working schedules for maraging steel.

Keywords

gamma iron hot workability/ductility kinetic analysis maraging steel processing maps 

References

  1. 1.
    Anon., “Making Shaping and Treating of Steel,” H.E. McGannon, ed., United States Steel Corp., Pittsburgh, PA, 1964.Google Scholar
  2. 2.
    Y.V.R.K. Prasad and T. Seshachryulu: “Modeling of Hot Deformation for Microstructural Control,” Intl. Mater. Rev., 1998, 43(6), pp. 243–58.Google Scholar
  3. 3.
    Y.V.R.K. Prasad, H.L. Gegel, S.M. Doraivelu, J.C. Malas, J.T. Morgan, K.A. Lark, and D.R. Barker: “Modeling of Dynamic Materials Behaviour in Hot Deformation: Forging of Ti-6242,” Metall. Trans. A, 1984, 15, p. 1883.Google Scholar
  4. 4.
    J.L. Robbins, O.C. Shepard, and O.D. Sherby: “Role of Crystal Structure on the Ductility of Pure Iron at Elevated Temperature,” J. Iron Steel Inst., 1961, 199, p. 175.Google Scholar
  5. 5.
    R.A. Reynolds and W.J. McG. Tegart: “The Deformation of Some Pure Irons by High Speed Torsion Over the Temperature Range 700–1250°C.” J. Iron Steel Inst., 1962, 200, p. 1044.Google Scholar
  6. 6.
    J.J. Jonas, C.M. Sellars, and J. McG. Tegart: “Strength and Structure Under Hot Working Conditions,” Metall. Rev. 1969, 14, p. 1–24.Google Scholar
  7. 7.
    Anon., Diffusion Data, F.H. Wohlbier, ed., Ohio Diffusion Info. Centre, P.O. Box 505, CH 4500, Solothurn, Switzerland; Vol. 3, No. 4, 1969, p. 394.Google Scholar
  8. 8.
    Anon., Diffusion Data, F.H. Wohlbier, ed., Ohio Diffusion Info. Centre, P.O. Box 505, CH 4500, Solothurn, Switzerland, Vol. 1, No. 3, 1969, p. 280.Google Scholar
  9. 9.
    W. Roberts: in Deformation Processing and Structure, G. Krauss, ed., ASM, Metals Park, OH, 1984, p. 109.Google Scholar
  10. 10.
    G.S. Avadhani: “Hot Deformation Mechanisms and Microstructural Evolution During Upset Forging of γ-Fe, Fe-5Ni, Fe-5Co, and Fe-5Mo Alloys and Maraging Steel,” Ph.D. Thesis, Indian Institute of Science, Bangalore, India, 2001.Google Scholar
  11. 11.
    M. Srinivas, G. Malkondaiah, and P. Rama Rao: “A First Report on Fracture Toughness of bcc Iron as Influenced by Solutes: Opposite Effects of Silicon and Cobalt,” Bull. Mater. Sci., 1988, 11, p. 329.Google Scholar
  12. 12.
    N. Ravichandran and Y.V.R.K. Prasad: “Influence of Oxygen on Dynamic Re-Crystallization During Hot Working of Polycrystalline Copper,” Mater. Sci. Eng., 1992, A156, p. 156.Google Scholar
  13. 13.
    Y.V.R.K. Prasad and S. Sasidhara: Hot Working Guide: A Compendium of Processing Maps, ASM International, Materials Park, OH, 1997.Google Scholar

Copyright information

© ASM International 2003

Authors and Affiliations

  • G. S. Avadhani
    • 1
  1. 1.Principal Research Scientist, Department of MetallurgyIndian Institute of ScienceBangaloreIndia

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