scholarly journals The Three-Dimensional Morphology and Distribution of CaS Inclusions in Continuous Casting Slab of Ni20Mn6 Steel

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3891
Author(s):  
Jing Chen ◽  
Jing Zhang ◽  
Shaobo Zheng ◽  
Jieyu Zhang
Keyword(s):  
Grain Boundary ◽  
Continuous Casting ◽  
Three Dimensional ◽  
Solidification Structure ◽  
Calcium Sulfide ◽  
Electrolytic Extraction ◽  
X Ray ◽  
Continuous Casting Slab ◽  
Austenite Grain ◽  
Austenite Grain Boundary

Calcium sulfide (CaS) inclusion with large and irregular shape is detrimental to the properties of steel. Understanding the shape and distribution of CaS inclusions in a continuous casting (CC) slab is of significance for improving the rolling properties. In this study, CaS inclusions were extracted from CC slab of Ni20Mn6 steel using the electrolytic extraction and investigated by scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX). The CaS inclusions morphologies vary with their locations in the CC slab and, thus, are classified into five categories. The thermodynamics calculated results showed that CaS inclusions precipitated at the end of solidification due to the microsegregation of sulfur and calcium in the interdendrite liquid and finally precipitated along the austenite grain boundary. The macrosegregation degree of solutes in different regions is one of the reasons that affect the size of CaS inclusion. The morphologies of CaS inclusion are affected by the solidification structure of slab and austenite grain boundary.

Three-Dimensional Observation and Growth Kinetics of Proeutectoid Ferrite Formed at Austenite Grain Boundary in a Low Carbon Microalloyed Steel

2007 ◽  
Vol 539-543 ◽  
pp. 4578-4583 ◽  
Author(s):  
Kai Ming Wu ◽  
A.M. Guo ◽  
Lin Cheng
Keyword(s):  
Grain Boundary ◽  
Growth Kinetics ◽  
Three Dimensional ◽  
Low Carbon ◽  
Austenite Grain ◽  
Ferrite Allotriomorphs ◽  
Proeutectoid Ferrite ◽  
Carbon Microalloyed ◽  
Austenite Grain Boundary ◽  
Kinetics Of

Three-dimensional observations of proeutectoid ferrite formed at grain boundary in an Fe-0.09%C-1.48%Mn vanadium microalloyed alloy was revealed by techniques of serial sectioning along with computer-aided reconstruction. The ferrite allotriomorphs nucleated at grain boundary edges were approximately prolate ellipsoids. Not all the ferrite allotriomorphs formed at grain boundary faces were oblate ellipsoids. The growth kinetics of ferrite allotriomorphs nucleated at grain boundary edges was greater than that of ferrite allotriomorphs nucleated at grain boundary faces.

Cavitation control in steels of high residual element content

1980 ◽  
Vol 295 (1413) ◽  
pp. 305-305 ◽  
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Prior Austenite ◽  
Low Alloy Steels ◽  
Boundary Zone ◽  
Austenite Grain ◽  
Alloy Steels ◽  
Austenite Grain Boundary ◽  
Prior Austenite Grain ◽  
Transverse Boundary

The cavitational mode of failure of prior austenite grain boundaries in bainitic creep-resisting low alloy steels is now well established as a principal factor in the high incidence of cracking problems which has developed on modern power plant in recent years. The microstructural features dominating the cavitation process at the reheat temperature in a ½CMV bainitic steel of high classical residual level have been determined. The prior austenite grain boundaries become zones of comparative weakness ca . 1 pm thick at 700 °C and are incapable of sustaining significant shear loads. Deformation is therefore initiated by a relaxation of load, through a process of prior austenite grain boundary zone shear, from inclined to transverse boundaries such that a concentration of normal stress develops across the latter. The overall deformation is thereafter determined by cavitation of the transverse boundary zones, the necessary inclined boundary displacements being accommodated by further grain boundary zone shear. Transverse boundary cavitation is shown to be an essentially time-independent process of localized ductile microvoid coalescence resulting from the plastic deformation of the boundary zone.

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