Modeling and Predication of Shrinkage Porosity Formation in Steel Ingot

Author(s):  
Chaojie Zhang ◽  
Yanping Bao ◽  
Min Wang ◽  
Lechen Zhang
2014 ◽  
Vol 790-791 ◽  
pp. 429-434 ◽  
Author(s):  
Sadaf Vazehrad ◽  
Jessica Elfsberg ◽  
Attila Diószegi

The purpose of this work is to investigate the relation between macro shrinkage porosity level and the level of graphite nodularity, gaseous elements and the size of eutectic colonies in compacted graphite iron. Also, the internal shrinkage-pore surfaces were analyzed by SEM and EDS techniques. It was found that samples with higher shrinkage porosity level, contained higher level of graphite nodularity and number of eutectic colonies. Also, samples with higher level of gaseous elements (Hydrogen and Nitrogen) showed higher tendency to shrinkage porosity formation. Austenite dendrites with different morphologies were observed inside the pores, indicating that were formed at different times during solidification, and the surface of the pores were covered with a layer of carbon film indicating that the pores were internal, with no contact to the atmosphere at elevated temperatures.


2021 ◽  
Vol 871 ◽  
pp. 59-64
Author(s):  
Ya Nan Zhao ◽  
Shi Guang Ba

The effect of riser necking ratio and taper on solidification process of 96T steel ingot have been studied numerically using the software package ProCAST. The results show that the solidification time decrease with the increase of riser necking ratio, and the position of shrinkage porosity moves up and the secondary porosity presents a tendency of increase, and the inclusions on the shoulder of body ingot decreases. The riser taper has little effect on the solidification process of heavy ingots.


2014 ◽  
Vol 941-944 ◽  
pp. 1782-1787
Author(s):  
Nan Lv ◽  
Yong Long Jin ◽  
Sheng Li Li ◽  
Xin Gang Ai

Shrinkage porosity and segregation defects are often found in an air cooled jumbo steel ingot, which will influence the quality of the final rolled plates.The solidification behaviours for a 60t jumbo slab ingot under varied cooling conditions were simulated using the ProCast software.The influences of different cooling speed on dendrite distribution and segregation were studied.The results show the jumbo slab ingot could freeze layer by layer when the heat transfer coeffcients of mould increase to 1000W·K-1·m-2. The thick finer chill zone were achieved. At the same time, the columnar crystals grow preferentially parrelling to the density of heat flow, and finer equiaxied crystals are formed in the core of the ingot. They all improve the microstructure and decrease the composition segregation of jumbo slab ingot.


Author(s):  
Shishira Bhagavath ◽  
Zhixuan Gong ◽  
Tim Wigger ◽  
Saurabh Shah ◽  
Bita Ghaffari ◽  
...  

2013 ◽  
Vol 336 ◽  
pp. 135-146 ◽  
Author(s):  
Zenon Ignaszak ◽  
Paweł Popielarski ◽  
Jakub Hajkowski

This paper highlights permanent development of process virtualization in the mechanical engineering industry, especially in the area of foundry. Virtualization is increasingly developed on the stage of product design and materials technologies optimization. Simultaneously, increasing expectations of design and process engineers regarding the practical effectiveness of applied simulation systems is observed. To enhance the knowledge in the scope of modelling and simulation in the foundry processes, one should be acquainted with the hard modelling based on physical-mathematical formula and also the soft modelling, burdened with simplifications resulting from both knowledge level on description of particular phenomena and level of theirs complexity. The trends observed in modelling of foundry processes and expectations of users compared with creators upgraded propositions new, additional modules based mostly on poorly tested theory are discussed. In such cases, each new module should be tested on sensitivity of additional parameters, which appear in these new modules. If needed and possible, these tests ought to be related to validation of the whole complex model containing such new modules. The purpose is to obtain simulation tools allowing the most possible realistic prognosis of the casting structure, including indication, with the highest possible probability, places in the casting that are endangered with the possibility of a gas and shrinkage porosity formation. These problems with elements of model validation are presented in the paper.


2016 ◽  
Vol 16 (2) ◽  
pp. 27-32 ◽  
Author(s):  
C. Zhang ◽  
Y. Bao ◽  
M. Wang ◽  
L. Zhang

Abstract In order to predict the distribution of shrinkage porosity in steel ingot efficiently and accurately, a criterion R√L and a method to obtain its threshold value were proposed. The criterion R√L was derived based on the solidification characteristics of steel ingot and pressure gradient in the mushy zone, in which the physical properties, the thermal parameters, the structure of the mushy zone and the secondary dendrite arm spacing were all taken into consideration. The threshold value of the criterion R√L was obtained with combination of numerical simulation of ingot solidification and total solidification shrinkage rate. Prediction of the shrinkage porosity in a 5.5 ton ingot of 2Cr13 steel with criterion R√L>0.21 m · °C1/2 · s−3/2 agreed well with the results of experimental sectioning. Based on this criterion, optimization of the ingot was carried out by decreasing the height-to-diameter ratio and increasing the taper, which successfully eliminated the centreline porosity and further proved the applicability of this criterion.


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