On Various Aspects of Decomposition of Austenite in a High-Silicon Steel During Quenching and Partitioning

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• 作者：Mahesh Chandra Somani (1)
  D. A. Porter (2)
  L. P. Karjalainen (1)
  R. D. K. Misra (3)
  
• 刊名：Metallurgical and Materials Transactions A
• 出版年：2014
• 出版时间：March 2014
• 年：2014
• 卷：45
• 期：3
• 页码：1247-1257
• 全文大小：1,157 KB
• 作者单位：Mahesh Chandra Somani (1)
  D. A. Porter (2)
  L. P. Karjalainen (1)
  R. D. K. Misra (3)
  
  1. Department of Mechanical Engineering, Centre for Advanced Steels Research, University of Oulu, Post Box 4200, 90014, Oulu, Finland
  2. Materials Engineering Laboratory, Department of Mechanical Engineering, Centre for Advanced Steels Research, University of Oulu, Post Box 4200, 90014, Oulu, Finland
  3. Laboratory for Excellence in Advanced Steel Research, Center for Structural and Functional Materials, Institute for Materials Research and Innovation, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA, 70504-4130, USA
  
• ISSN：1543-1940

文摘

Using a Gleeble thermomechanical simulator, a high-silicon steel (Fe-0.2C-1.5Si-2.0Mn-0.6Cr) was laboratory hot-rolled, re-austenitized, quenched into the M s-em class="a-plus-plus">M f range, retaining 15 to 40?pct austenite at the quench stop temperature (T Q), and annealed for 10 to 1000?seconds at or above T Q in order to better understand the mechanisms operating during partitioning. Dilatometer measurements, transmission electron microscopy, and calculations showed that besides carbon partitioning, isothermal martensite and bainite form at the partitioning temperature. While isothermal martensite formation starts almost immediately after quenching with the rate of volume expansion dropping all the time, the beginning of bainite formation is marked by a sudden increase in the rate of expansion. The extent of its formation depends on the partitioning temperature following TTT diagram predictions. At the highest partitioning temperatures martensite tempering competes with partitioning. Small fractions of bainite and high-carbon martensite formed on cooling from the partitioning temperature. The average carbon content of the austenite retained at room temperature as determined from XRD measurements was close to the carbon content estimated from the M s temperature of the martensite formed during the final cooling.