Journal Published Online: 04 April 2011
Volume 8, Issue 4

Isothermal Martensite Formation at Sub-Zero Temperatures

CODEN: JAIOAD

Abstract

Sub-zero treatment of steels with an Mf below 0°C relies (partly) on a continuation of the martensite formation. The present work reports on the observation of isothermal martensite formation in the sub-zero temperature regime for two steels: AISI 1070 and AISI 52100. Samples were austenitized, quenched in oil, and thereafter investigated with vibrating sample magnetometry, which allows a quantitative assessment of the fraction of retained austenite as a function of the sub-zero temperature and time. Isothermal martensite formation was observed on interrupting the continuous cooling (5 K/min) at temperatures in the range of 80–233 K. The kinetics of isothermal martensite formation depends strongly on the temperature and can be described by Johnson–Mehl–Avrami–Kolmogorov kinetics. Isothermal experiments with dilatometry indicated the occurrence of a volume increase on isothermal holding, consistent with a continuation of the martensitic transformation. On prolonged isothermal holding, a volume reduction was observed for AISI 52100, but not for AISI 1070.

Author Information

Stojko, Allan
Grundfos A/S, Bjerringbro, Denmark
Hansen, Mikkel
Technical Univ. of Denmark, Dept. of Micro- and Nanotechnology, Kgs. Lyngby, Denmark
Slycke, Jan
Formerly at SKF Engineering and Research Centre, Nieuwegein, The Netherlands
Somers, Marcel
Technical Univ. of Denmark, Dept. of Mechanical Engineering, Kgs. Lyngby, Denmark
Pages: 9
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Stock #: JAI103459
ISSN: 1546-962X
DOI: 10.1520/JAI103459