Paper Titles
Effect of Carbon on Work Hardening Behavior of 18%Ni Martensitic Steel
p.4783
Nano-Carbides and the Strength of Steels as Assessed by Electrical Resistivity Studies
p.4789
Modeling of Microstructure Evolution of Athermal Transformation of Lath Martensite
p.4795
The Ultrahigh Ductility of an Ultrahigh Carbon Steel Containing 3%Si
p.4801
Ultra Rapid Softening of High Strength Structural Steels by Thermomechanical Treatment
p.4807
Coarsening Behavior of Nanometer-Sized Carbides in Hot-Rolled High Strength Sheet Steel
p.4813
Microstructural Features of 'Quenching and Partitioning': A New Martensitic Steel Heat Treatment
p.4819
Thermomechanical Treatments of Ultrahigh Carbon Steels and Optimal Microstructures to Improve Toughness
p.4826
Substructure and Crystallography of Degenerate Pearlite in an Fe-C Binary Alloy
p.4832

Ultra Rapid Softening of High Strength Structural Steels by Thermomechanical Treatment

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Abstract:

This study aims to shorten the softening treatment period as possible in high strength structural steels. The steel used is SCM440 steel. As an initial microstructure, martensite, bainite, pearlite and complicated microstructure consisting of ultrafine polygonal, martensite and equiaxed cementite were extensively examined to understand their softening process on aging at 973K. These initial microstructures were prepared by heat or thermomechanical treatment. Their initial Vickers hardness (Hv(10kgf)) were 634, 281, 219 and 238, respectively. It is noteworthy that within five minutes on aging hardness of the complicated microstructure reached lower than Hv200, while it took more than several hours for other initial microstructures. A quantitative evaluation of microstructures appears to help in understanding the mechanism of the softening kinetics.

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Periodical:

Materials Science Forum (Volumes 539-543)

Pages:

4807-4812

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.539-543.4807

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Online since:

March 2007

Authors:

Yoshitaka Adachi, Kaneaki Tsuzaki

Keywords:

Cementite, High Strength Steel (HSS), Softening, Spheroidizing, Thermomechanical Treatment (TMT)

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© 2007 Trans Tech Publications Ltd. All Rights Reserved

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