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Journal of Materials Science

, Volume 31, Issue 3, pp 707–711 | Cite as

Secondary carbide precipitation in an 18 wt%Cr-1 wt% Mo white iron

  • G. L. F. Powell
  • J. V. Bee
Papers

Abstract

High chromium (18%) white irons solidify with a substantially austenitic matrix supersaturated with chromium and carbon. The austenite is destabilized by a hightemperature heat treatment which precipitates chromium-rich secondary carbides. In the as-cast condition the eutectic M7Ca3 carbides are surrounded by a thin layer of martensite and in some instances an adjacent thicker layer of lath martensite. The initial secondary carbide precipitation occurs on sub-grain boundaries during cooling of the as-cast alloy. After a short time (0.25 h) at the destabilization temperature of 1273 K, cuboidal M23C6 precipitates within the austenite matrix with the cube-cube orientation relationship. After the normal period of 4 h at 1273 K, there is a mixture of M23C6 and M7C3 secondary carbides and the austenite is sufficiently depleted in chromium and carbon to transform substantially to martensite on cooling to room temperature.

Keywords

Carbide Chromium Heat Treatment Austenite Martensite 
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.

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Copyright information

© Chapman & Hall 1996

Authors and Affiliations

  • G. L. F. Powell
    • 1
  • J. V. Bee
    • 2
  1. 1.CSIRO Division of Manufacturing TechnologyWoodville
  2. 2.Department of Mechanical EngineeringUniversity of Adelaide

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