Effects of Transformation Temperature on Variant Grouping of Bainitic Ferrite in Low Carbon Steel

2011 ◽  
Vol 172-174 ◽  
pp. 155-160
Author(s):  
Naoki Takayama ◽  
Goro Miyamoto ◽  
Tadashi Furuhara
Keyword(s):  
Transformation Temperature ◽  
Electron Backscatter Diffraction ◽  
Lath Martensite ◽  
Bainitic Ferrite ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Low Alloy Steel ◽  
Bainite Structure ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Effects of transformation temperature on variant grouping tendency of bainitic ferrite in a low carbon low alloy steel transformed isothermally are investigated by means of electron backscatter diffraction analysis. Baintic variants of Kurdjumov-Sachs (K-S) orientation relationship belonging to the same Bain correspondence tend to form adjacently in the bainite structure formed at 823K, while the K-S variants sharing the same close-packed plane parallel relation form adjacently in the bainite structure formed at 723K and lath martensite formed by quenching.

The Application of 3D-EBSD for Investigating Texture Development in Metals and Alloys

2011 ◽  
Vol 702-703 ◽  
pp. 469-474
Author(s):  
Michael Ferry ◽  
M. Zakaria Quadir ◽  
Nasima Afrin Zinnia ◽  
Lori Bassman ◽  
Cassandra George ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Electron Backscatter Diffraction ◽  
Ion Beam ◽  
Low Carbon Steel ◽  
Texture Development ◽  
Data Generation ◽  
Low Carbon ◽  
Resolution Electron ◽  
Multi Phase ◽  
Backscatter Diffraction

A focused ion beam (FIB) coupled with high resolution electron backscatter diffraction (EBSD) has emerged as a useful tool for generating crystallographic information in reasonably large volumes of microstructure. In principle, data generation is reasonably straightforward whereby the FIB is used as a high precision serial sectioning device for generating consecutive milled surfaces suitable for mapping by EBSD. However, there are several challenges facing the technique including the need for accurate reconstruction of the EBSD slice data and the development of methods for representing the myriad microstructural features of interest including, for example, orientation gradients arising from plastic deformation through to the structure of grains and their interfaces in both single-phase and multi-phase materials. This paper provides an overview of the use of 3D-EBSD in the study of texture development in alloys during deformation and annealing and includes an update on current research on the crystallographic nature of microbands in some body centred and face centred cubic alloys and the nucleation and growth of grains in an extra low carbon steel.

scholarly journals Revealing the Unexpected Two Variant Pairing Shifts Due to Temperature Change in a Single Bainitic Medium Carbon Steel

2021 ◽  
Author(s):  
Adam Ståhlkrantz ◽  
Peter Hedström ◽  
Niklas Sarius ◽  
Annika Borgenstam
Keyword(s):  
Carbon Steel ◽  
Electron Backscatter Diffraction ◽  
Low Carbon Steel ◽  
Medium Carbon Steel ◽  
Low Carbon ◽  
Medium Carbon ◽  
Strong Relation ◽  
Upper Bainite ◽  
The Common ◽  
Backscatter Diffraction

AbstractThe microstructure of a low alloy medium carbon bainitic steel, austempered in the temperature range 275 °C to 450 °C has been investigated by detailed electron backscatter diffraction and variant pairing analysis. It is observed that the variant pairing tendency has two distinct changes with varying temperature. At low temperature V1-V6 is the most frequent, whereas V1-V2 is the most frequent at intermediate temperature and at the highest temperature, V1-V4 dominates. This is distinct from the literature on low carbon steel where only two dominant variants pairs, related to the common distinction of bainite into lower and upper bainite, are typically reported. The change of the variant pairing in bainite also has many similarities with the change of variant pairing in martensite when its carbon content changes. Another observation is that the morphological orientation of cementite in the bainite has a strong relation with the variant pairing at lower austempering temperatures.

Crystallographic Features of Low-Carbon Bainite Formed under Non-Isothermal Conditions

2013 ◽  
Vol 762 ◽  
pp. 110-115 ◽  
Author(s):  
S.N. Panpurin ◽  
Nikolay Y. Zolotorevsky ◽  
Yuri F. Titovets ◽  
A.A. Zisman ◽  
E.I. Khlusova
Keyword(s):  
Cooling Rate ◽  
Electron Backscatter Diffraction ◽  
Bainitic Ferrite ◽  
Low Carbon ◽  
Austenite Grain Size ◽  
Orientation Data ◽  
Austenite Grain ◽  
Low Carbon Bainite ◽  
Backscatter Diffraction ◽  
Parent Austenite

The effects of cooling rate and austenite structure on bainite formation was investigated by means of electron backscatter diffraction analysis and processing of obtained orientation data. Variant pairing tendency of bainitic ferrite was found to depend on the austenite grain size, austenite plastic deformation and cooling rate. In the bainite formed at low cooling rate the variant pairs having the same Bain axis correspondence are more frequent, while at high cooling rate the variant pairs having the same parallel correspondence of close-packed planes are formed side by side preferably. At the same time, these features are influenced significantly by structural state of parent austenite.

Determination of Dislocation Density in Lath Martensite by Means of Electron Backscatter Diffraction

2017 ◽  
Vol 885 ◽  
pp. 275-279 ◽  
Author(s):  
Péter János Szabó ◽  
András Csóré
Keyword(s):  
Dislocation Density ◽  
Martensitic Steel ◽  
Electron Backscatter Diffraction ◽  
Lath Martensite ◽  
Electron Backscatter ◽  
Density Values ◽  
Cold Rolled ◽  
Backscatter Diffraction ◽  
Scanning Electron

As a novel procedure for determining dislocation density, a software was improved with which data obtained by Scanning Electron Microscope (SEM) measurements can be collected and the value of superficial dislocation density can be calculated. Applying this method we investigated cold rolled lath martensitic steel samples. Besides dislocation density values, microstructure mapped by Electron Backscatter Diffraction (EBSD) will be discussed.

Microstructure–Property Relationship in 22mm Thick X80 Coil Skelp

2010 ◽  
Author(s):  
M. Liebeherr ◽  
N. Bernier ◽  
D. Le`bre ◽  
N. Ilic´ ◽  
D. Quidort
Keyword(s):  
Grain Size ◽  
Impact Toughness ◽  
Electron Backscatter Diffraction ◽  
Bainitic Ferrite ◽  
Hot Strip Mill ◽  
Low Carbon ◽  
Welded Pipe ◽  
Hot Rolled ◽  
Backscatter Diffraction ◽  
The Impact

The progress in the development of heavy gauge X80 linepipe steel on coil at ArcelorMittal was recently rewarded with a 6000 ton commercial order for the production of 21.6mm wall thickness spiral welded pipe. The further product development is concentrating on the improvement of the impact toughness at low temperatures. Research is currently focussing on the relationship between the mechanical properties and the microstructure of the steels. In the present study, two industrially hot rolled X80 steels with thickness 21.6mm were investigated. The steels had the same chemical composition but were processed with different parameter sets in the hot strip mill. The two resulting low-carbon bainitic microstructures were composed predominantly of quasi-polygonal ferrite and globular bainitic ferrite / bainitic ferrite, respectively. Emphasis of the microstructure and property characterisation was laid on through-thickness gradients of grain size, hardness, texture, impact toughness and tensile properties. Accordingly, the materials were characterised at different positions in the thickness. Grain size and texture were determined by means of Electron Backscatter Diffraction (EBSD). Sub-size Charpy as well as sub-thickness tensile test specimens were taken at different positions in the cross section. The results show that the link between microstructure and properties is not at all obvious. The influence of mean grain size, grain size distribution and texture is discussed in detail.

scholarly journals An Accurate Method for Crystallographic Reconstruction of Parent Austenite from Inherited Martensite in a Low-Alloy Steel

Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 358 ◽  
Author(s):  
Daokuan Wang ◽  
Junsong Jin ◽  
Qiaomin Li ◽  
Xinyun Wang
Keyword(s):  
Electron Backscatter Diffraction ◽  
Accurate Method ◽  
Reconstruction Method ◽  
Low Alloy Steels ◽  
Low Alloy Steel ◽  
Reconstruction Procedure ◽  
Electron Backscatter ◽  
Alloy Steels ◽  
Backscatter Diffraction ◽  
Parent Austenite

The microstructure of austenite at high temperatures, which cannot be reserved at room temperatures, determines the properties of its transformed phase in low-alloy steels. Consequently, an accurate method is herein developed to reconstruct local orientations of the parent austenite ( γ ) phase from electron backscatter diffraction maps of the martensite ( α ′ ) microstructure. The orientation map of α ′ is cropped into a grid of data squares as the reconstruction unit. The cropped square is then divided into the square inherited from only one γ grain and the square inherited from more than one γ grain. The local orientations around parent γ grain boundaries are more accurately determined using a newly proposed reconstruction criterion. Furthermore, the solution spaces for the orientation relationship and the parent γ orientation are refined, which simultaneously improves the calculation accuracy and efficiency of reconstruction procedure. The validated reconstruction method is applied to obtain local orientations of the deformed γ microstructure accurately.

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