scholarly journals Comparison of the Microstructure of M2 Steel Fabricated by Continuous Casting and with a Sand Mould

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 560
Author(s):  
Jinwen Zhang ◽  
Zhigang Zhao ◽  
Wenxian Wang ◽  
Yutian Wang
Keyword(s):  
Grain Size ◽  
Continuous Casting ◽  
Cooling Rate ◽  
Continuous Caster ◽  
Casting Process ◽  
Sand Mold ◽  
Average Grain Size ◽  
Kg Medium ◽  
The Relationship ◽  
Continuous Casting Billet

AISI M2 steel was smelted in a 150 kg medium-frequency induction furnace and cast to form round billets with a cross-section diameter of 100 mm via a vertical continuous caster and sand mold. The secondary dendrite arm spacing (λ2), cooling rates, permeability and size and distribution of grains and network carbides of the two billets were studied. The results show that the continuous casting process can effectively decrease the λ2 value, permeability and size of the grains and carbides and improve the distribution of the grains and carbides during solidification. The λ2 values of the billets cast with a sand mold and continuous caster are 37.34 μm and 21.14 μm, respectively, and the cooling rate is 3.6 K·s−1 and 12.0 K·s−1, respectively. The area fractions of carbides at the center of the billets cast with the sand mold and continuous caster are 0.24 and 0.16, respectively, and increase by 27.7% and 25.4%, respectively, compared with their average values. The average grain size of billets cast with the sand mold and continuous caster is 69.4 μm and 50.5 μm, respectively. Compared with the sand mold billet, the grain size at the center of the continuous casting billet is reduced by 25.5%. The relationship between the grain size and cooling rate is presented in this paper.

Microstructure Prediction by Finite Element Analysis during Hot Rolling of Magnesium Alloy Sheets

2015 ◽  
Vol 661 ◽  
pp. 105-112
Author(s):  
Yeong Maw Hwang ◽  
Tso Lun Yeh
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Optimal Conditions ◽  
Compression Tests ◽  
Element Analysis ◽  
Grain Sizes ◽  
Average Grain Size ◽  
Microstructure Prediction ◽  
Alloy Microstructure ◽  
The Relationship

Material’s plastic deformation by hot forming processes can be used to make the materials generate dynamic recrystallization (DRX) and fine grains and accordingly products with more excellent mechanical properties, such as higher strength and larger elongation can be obtained. In this study, compression tests and water quenching are conducted to obtain the flow stress of the materials and the grain size after DRX. Through the regression analysis, prediction equations for the magnesium alloy microstructure were established. Simulations with different rolling parameters are conducted to find out the relationship between the DRX fractions or grain sizes of the rolled products and the rolling parameters. The simulation results show that rolling temperature of 400°C and thickness reduction of 50% are the optimal conditions. An average grain size of 0.204μm-0.206μm in the microstructure is obtained and the strength and formability of ZK60 magnesium alloys can be improved.

scholarly journals Effect of Sc on the Hot Cracking Properties of 7xxx Aluminum Alloy and the Microstructure of Squeeze Castings

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6881
Author(s):  
Yongtao Xu ◽  
Zhifeng Zhang ◽  
Zhihua Gao ◽  
Yuelong Bai ◽  
Purui Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Aluminum Alloy ◽  
Performance Test ◽  
Casting Process ◽  
Hot Cracking ◽  
Hot Tearing ◽  
Average Grain Size ◽  
Cylindrical Parts ◽  
Series Aluminum Alloy

In this paper, the effect of adding the refiner Sc to the high Zn/Mg ratio 7xxx series aluminum alloy melt on the hot tearing performance, microstructure, and mechanical properties of the alloy is studied. The hot tearing performance test (CRC) method is used to evaluate the hot tearing performance of the alloy. The squeeze casting process was used to form solid cylindrical parts to analyze the structure and properties of the alloy. This study shows that the hot cracking sensitivity of the alloy after the addition of the refiner Sc is significantly reduced. The ingot grain size is significantly reduced, and the average grain size is reduced from about 86 μm to about 53 μm. While the mechanical properties are significantly improved, and the tensile strength reduced from 552 MPa is increased to 571 MPa, and the elongation rate is increased from 11% to 14%.

scholarly journals The Effect of Cooling Rate on Mechanical Properties of Carbon Steel (St 35)

2014 ◽  
Vol 7 (1) ◽  
pp. 109-118
Author(s):  
Jenan Mohammed Nagie
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Carbon Steel ◽  
Cooling Rate ◽  
Experimental Results ◽  
Heat Treated ◽  
Before And After ◽  
Water Media ◽  
The Relationship

This paper is aimed to study the effect of cooling rate on mechanical properties of Steel 35. Specimens prepared to apply tensile, torsion, impact and hardness tests.Many prepared specimens heat treated at (850ºC) for one hour and subsequently were cooled by three different media [Water-Air-furnace] to show the effect of Medias cooling rate on mechanical properties. Microstructures of all specimens examined before and after heat treatment by an optical microscopy.To figure the phases obtained after heat treatment and its effect on the mechanical properties Experimental results have shown that the microstructure of steel can be changed and significantly improved by varying line cooling rate thus, improving one property will effect on the others because of the relationship between all properties.In water media tensile, torsion and hardness improved while impact results reduced. Air media contributed in improving most of the mechanical properties because of grain size homogeneity. At furnace media ductility and impact improved

Effect of Cooling Rate on the Microstructure and Precipitates of Directional Solidified 50W600 Non-oriented Silicon Steel

2013 ◽  
Vol 32 (6) ◽  
pp. 597-603
Author(s):  
Yong Wan ◽  
Wei-qing Chen ◽  
Shao-jie Wu
Keyword(s):  
Grain Size ◽  
Cooling Rate ◽  
Volume Fraction ◽  
Silicon Steel ◽  
Growth Region ◽  
State Growth ◽  
Average Size ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
The Relationship

AbstractThe microstructure, morphologies of precipitates in directional solidified 50W600 non-oriented silicon steel with three cooling rates (0.095, 0.33 and 4.28 °C/s) were investigated. The results showed that the morphology of solid-liquid interface evolved from cellular to cellular dendritic, and then to dendritic with an increase of cooling rate. The grain size of specimen in the steady-state growth region decreased with increasing cooling rate. The precipitates in the steel were mainly four types as follows: AlN, MnS, AlN-MnS and Fe3C. The amount and volume fraction of precipitates firstly increased and then decreased with increasing cooling rate, and reached maximum values in the specimen with a cooling rate of 0.76 °C/s. The average size of precipitates decreased gradually with increasing cooling rate. The relationship between the average size of precipitates and cooling rate was D = 75.762·R−0.190.

The Effect of Grain Size Distribution on the Mechanical Properties of Nanometals

2008 ◽  
Vol 140 ◽  
pp. 185-190 ◽  
Author(s):  
T.B. Tengen ◽  
Tomasz Wejrzanowski ◽  
R. Iwankiewicz ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Flow Stress ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Deformation Mechanisms ◽  
Average Grain Size ◽  
Significant Interest ◽  
Size Dispersion ◽  
The Relationship

Predicting the properties of a material from knowledge of the internal microstructures is attracting significant interest in the fields of materials design and engineering. The most commonly used expression, known as Hall-Petch Relationship (HPR), reports on the relationship between the flow stress and the average grain size. However, there is much evidence that other statistical information that the grain size distribution in materials may have significant impact on the mechanical properties. These could even be more pronounced in the case of grains of the nanometer size, where the HPR is no longer valid and the Reverse-HPR is more applicable. This paper proposes a statistical model for the relationship between flow stress and grain size distribution. The model considered different deformation mechanisms and was used to predict mechanical properties of aluminium and copper. The results obtained with the model shows that the dispersion of grain size distribution plays an important role in the design of desirable mechanical properties. In particular, it was found that that the dependence of a material’s mechanical properties on grain size dispersion also follows the HPR to Inverse-HPR type of behaviour. The results also show that copper is more sensitive to changes in grain size distribution than aluminium.

scholarly journals Method of Verification of Carbon Segregation Ratio Determined with Experimental Methods

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 499
Author(s):  
Jan Falkus ◽  
Katarzyna Miłkowska-Piszczek ◽  
Paweł Krajewski ◽  
Tomasz Ropka
Keyword(s):  
Continuous Casting ◽  
Continuous Caster ◽  
High Carbon Steel ◽  
Metal Flow ◽  
Casting Process ◽  
Segregation Ratio ◽  
Carbon Steels ◽  
High Carbon ◽  
Continuous Casting Process ◽  
Carbon Segregation

The problem of macrosegregation of alloying elements occurring during cast strand solidification in the continuous casting process is still valid; it is the subject of numerous experiments and theoretical considerations. A large percentage of this research is dedicated to carbon segregation, which, for understandable reasons, is vital for the production of high-carbon steels. The background knowledge on the mechanism of segregation occurrence indicates that it is a very complex effect, and a broad range of factors influencing the continuous casting process need to be considered. Therefore, it is difficult to translate information (provided by complex models of metal flow through a diphase area at the solidification interface of a cast strand) into practical engineering recommendations to reduce the macrosegregation effect. The presented study shows the latest research related to the carbon macrosegregation effect for selected high-carbon steel grades cast with a continuous caster. Problems related to the recording of the effect concerned have been pointed out. The second part of the paper presents the influence of selected casting parameters on carbon macrosegregation intensity when casting 160 × 160 billets with a six-strand caster. In this case, the main subject of the research was the influence of the casting speed on macrosegregation intensity. In the following step, an attempt was made to find the relationship between the cast strand structure and the distribution of carbon content on its cross-section. The ultimate objective of the presented study was to find an answer to the question on the technological capabilities of restricting the segregation effect.

β Microtexture Analysis in Correlation with HCP Textured Regions Observed in a Forged Near Alpha Titanium Alloy

2005 ◽  
Vol 105 ◽  
pp. 127-132 ◽  
Author(s):  
Philippe Bocher ◽  
Mohammad Jahazi ◽  
Lionel Germain ◽  
Priti Wanjara ◽  
Nathalie Gey ◽  
...  
Keyword(s):  
Grain Size ◽  
Titanium Alloy ◽  
Thermomechanical Processing ◽  
Continuous Dynamic Recrystallization ◽  
Orientation Image Microscopy ◽  
Average Grain Size ◽  
Alpha Titanium ◽  
Imi 834 ◽  
Continuous Dynamic ◽  
The Relationship

The presence of hcp regions with grains having relatively close orientations has been reported in commercial near alpha titanium billets (IMI 834, Ti 6246, etc). The size of these textured regions (called macrozones) is significantly larger than the average grain size of the microstructure observed after thermomechanical processing. The elongated shape of these large hcp regions suggests that they are eventually related to large prior b grains that pancaked during the ingot break down process. In this contribution, Orientation Image Microscopy was used to study the relationship between the hcp local microtexture heterogeneities and the prior b orientations. Specifically, the orientations of the primary (equiaxed) ap grains and the secondary (lamellar) as colonies produced after the transformation of the b phase were discriminated from OIM maps. Furthermore, from the as inherited OIM map, it was possible to reconstruct the corresponding b OIM map over large regions. The analysis showed that the large hcp macrozones observed in the as received material are not related to corresponding bcc macrozones. However, within an hcp macrozone, various clusters of b grains with similar orientations can be found. In such coherent regions, randomly orientated b grains were also observed, which could be related to microstructural changes during deformation (continuous dynamic recrystallization) as suggested by hot deformation results.

Development and Application of CISDI Online Slab Quality Diagnosis & Analysis System

2012 ◽  
Vol 542-543 ◽  
pp. 647-652
Author(s):  
Shui Gen Wang ◽  
Ke Feng ◽  
Zhi Wei Han ◽  
Yi Wen Kong ◽  
Jian Feng Cao
Keyword(s):  
Continuous Casting ◽  
Process Analysis ◽  
Continuous Caster ◽  
Casting Process ◽  
Internal Crack ◽  
Quality Level ◽  
Strain Calculation ◽  
Solidification Simulation ◽  
Analysis System ◽  
Quality Diagnosis

An online slab quality diagnosis & analysis system named CISDI_SQDS ONLINE R2011 has been presented in this paper. The system is based on mechanism of defects, which mainly refer to surface crack & internal crack, heat-transfer & solidification simulation, stress & strain calculation and metallurgical process analysis about continuous casting. Combining with BP neural network, several kinds of quality loss factors are used to describe the possibility of inducement. Meanwhile, the respective crack formation indexes are introduced to be the theoretical reference data for slab quality level evaluation and guiding production. The CISDI_SQDS ONLINE R2011 system was firstly applied on the No.1 Slab Continuous Caster of Bayi Steel in China. It is preliminary proved that the model is reliable and reasonable. It can be widely used as an important theoretical tool for prediction & control for slab quality in continuous casting process.

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