Processing and Stability of Ultrafine Grained Structures in Some Microalloy Steels

L.X. Pan; L. Pentti Karjalainen; Mahesh Chandra Somani

doi:10.4028/www.scientific.net/MSF.500-501.363

Paper Titles

Kinetics and Microstructural Aspects of the Coupling between Deformation at the Austenitic State and Ferrite Transformation in Carbon Steels
p.329

Contribution to the Understanding of Austenite Stability in a 12Cr-9Ni-4Mo Maraging Steel
p.339

Microstructure Evolution in Fine-Grained Microalloyed Steels
p.347

Factors Limiting the Achievable Ferrite Grain Refinement in Hot Worked Microalloyed Steels
p.355

Processing and Stability of Ultrafine Grained Structures in Some Microalloy Steels
p.363

Study on Ferrite Intragranular Nucleation in a V-Microalloyed Steel
p.371

In Situ X-Ray Diffraction Measurements of Deformation-Induced Austenite to Martensite Transformation in a Multiphase TRIP Steel
p.379

Characterisation and Quantification of Complex Bainitic Microstructures in High and Ultra-High Strength Linepipe Steels
p.387

Austenite Decomposition in Low Carbon Steels with Microalloy Additions
p.395

HomeMaterials Science ForumMaterials Science Forum Vols. 500-501Processing and Stability of Ultrafine Grained...

Processing and Stability of Ultrafine Grained Structures in Some Microalloy Steels

Abstract:

The dynamic strain-induced transformation (DSIT) of ferrite from austenite in intense deformation at temperatures close to Ar3 were applied to one C-Mn steel and several Nb and Nb-Ti microalloy steels to obtain an ultrafine ferrite grain size. As another route the static recrystallisation of severely cold-rolled martensite (SRM) was utilized. It was found that in the DSIT route a fine prior austenite grain size was crucial to form ferrite with the grain size of 1-3 µm with a considerable fraction of a secondary phase, carbide aggregate/pearlite or martensite. Grain sizes achieved were somewhat finer in steels with a higher microalloying content. In the SRM route, the ferrite grain size of 1-1.5 µm was obtained by using the cold rolling of 80-90% reduction. Thermal stability of the ultrafine-grained structures, especially those from the DSIT route, was found to be excellent. In electron or laser beam welding of 1-2.5 mm sheets neither any coarse-grained zone existed in the heat-affected zone, nor did form any softened zone.

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Periodical:

Materials Science Forum (Volumes 500-501)

Pages:

363-370

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.500-501.363

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Online since:

November 2005

Authors:

L.X. Pan, L. Pentti Karjalainen, Mahesh Chandra Somani

Keywords:

Cold Rolling, Martensite, Microalloyed Steel, Recrystallisation Annealing, Strain Induced Transformation, Thermal Stability, Ultra-Fine Ferrite Grain Size, Welding

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References

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