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Karasev, Andrey
Publications (10 of 17) Show all publications
Al-Saadi, M., Sandberg, F., Hulme-Smith, C., Karasev, A. & Jönsson, P. (2019). A study of the static recrystallization behaviour of cast Alloy 825 after hot-compressions. Paper presented at 7th International Conference on Recrystallization and Grain Growth, Ghent,August 4-9, 2019. IOP Conference Series: Materials Science and Engineering, 1270
Open this publication in new window or tab >>A study of the static recrystallization behaviour of cast Alloy 825 after hot-compressions
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2019 (English)In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Journal of Physics, Vol. 1270Article in journal, Editorial material (Refereed) Published
Abstract [en]

The static recrystallization behaviour of a columnar and equiaxed Alloy 825 material was studied on a Gleeble-3800 thermo-simulator by single-hit compression experiments. Deformation temperatures of 1000-1200 °C, a strain of up to 0.8, a strain rate of 1s-1, and relaxation times of 30, 180, and 300 s were selected as the deformation conditions to investigate the effects of the deformation parameters on the SRX behaviour. Furthermore, the influences of the initial grain structures on the SRX behaviors were studied. The microstructural evolution was studied using optical microscopy and EBSD. The EBSD measurements showed a relaxation time of 95 % for fractional recrystallization grains, 𝑡95, in both structures, was less than 30 seconds at the deformation temperatures 1100 °C and 1200 °C. However, fewer than 95% of recrystallized grains recrystallized when the deformation temperature was lowered to 1000 °C. From the grain-boundary misorientation distribution in statically recrystallized samples, the fraction of high-angle grain boundaries decreased with an increasing deformation temperature from 1000 °C to 1200 °C for a given relaxation time. This was attributed to grain coarsening

Keywords
Alloy 825, Static recrystallization, hot compression, Gleeble-3800 thermo simulator
National Category
Metallurgy and Metallic Materials
Research subject
Materials Science and Engineering
Identifiers
urn:nbn:se:kth:diva-258210 (URN)10.1088/1742-6596/1270/1/012023 (DOI)
Conference
7th International Conference on Recrystallization and Grain Growth, Ghent,August 4-9, 2019
Available from: 2019-09-10 Created: 2019-09-10 Last updated: 2019-09-10
Wang, Y., Karasev, A. & Jönsson, P. G. (2019). An Investigation of Non-Metallic Inclusions in Different Ferroalloys using Electrolytic Extraction. Metals, 9(6)
Open this publication in new window or tab >>An Investigation of Non-Metallic Inclusions in Different Ferroalloys using Electrolytic Extraction
2019 (English)In: Metals, ISSN 2075-4701, Vol. 9, no 6Article in journal (Refereed) Published
Abstract [en]

Ferroalloys are integral constituents of the steelmaking process, since non-metallic inclusions (NMIs) from ferroalloys significantly influence the transformation of inclusions present in liquid steel or they are directly involved in casted steel. In this study, the characteristics of inclusions (such as the number, morphology, size, and composition) in different industrial ferroalloys (FeV, FeMo, FeB, and FeCr) were investigated using the electrolytic extraction (EE) technique. After extraction from the ferroalloy samples and filtration of the solution, the inclusions were investigated on a film filter. The three-dimensional (3D) investigations were conducted using a scanning electron microscopy in combination with energy dispersive spectroscopy (SEM-EDS). The characteristics of inclusions observed in the ferroalloys were compared with previous results and discussed with respect to their possible behaviors in the melt and their effects on the quality of the cast steels. The particle size distributions and floatation distances were plotted for the main inclusion types. The results showed that the most harmful inclusions in the ferroalloys investigated are the following: pure Al2O3 and high Al2O3-containing inclusions in FeV alloys; pure SiO2 and high SiO2-containing inclusions in FeMo alloys; Al2O3 and SiO2-containing inclusions in FeB alloys; and MnO-Cr2O3, Al2O3, and Cr2O3-based inclusions in FeCr alloys.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
ferroalloy, non-metallic inclusions, electrolytic extraction, steel quality
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-255578 (URN)10.3390/met9060687 (DOI)000475356500071 ()
Note

QC 20190802

Available from: 2019-08-02 Created: 2019-08-02 Last updated: 2019-08-02Bibliographically approved
Nabeel, M., Alba, M., Karasev, A., Jönsson, P. G. & Dogan, N. (2019). Characterization of Inclusions in 3rd Generation Advanced High-Strength Steels. Metallurgical and materials transactions. B, process metallurgy and materials processing science, 50(4), 1674-1685
Open this publication in new window or tab >>Characterization of Inclusions in 3rd Generation Advanced High-Strength Steels
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2019 (English)In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 50, no 4, p. 1674-1685Article in journal (Refereed) Published
Abstract [en]

Samples taken from laboratory-produced 3rd generation advanced high-strength steels, solidified at a low cooling rate, have been investigated to study the characteristics of non-metallic inclusions. Two steels, containing 2 and 5 pct Mn content, were produced for this purpose. A higher number of total inclusions were observed in 5 pct Mn steel. The four main types of inclusions observed were Al2O3, AlN, MnS, and AlSiMn-oxide. These classes were divided into subclasses according to variations in their chemistry. The major subclasses of AlN inclusions are either plate-like or regular in shape and have different size distributions. Thermodynamic calculations suggest that plate-like AlN inclusions are formed at the initial stage of solidification, while faceted/regular-shaped inclusions are precipitated toward the end of solidification. Moreover, it was found that the size of nitride inclusions is related to their N content. This phenomenon is discussed from the viewpoint of nucleation theory.

Place, publisher, year, edition, pages
Springer, 2019
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-255553 (URN)10.1007/s11663-019-01605-0 (DOI)000475698700016 ()2-s2.0-85066623028 (Scopus ID)
Note

QC 20190808

Available from: 2019-08-08 Created: 2019-08-08 Last updated: 2019-08-08Bibliographically approved
Sidorova, E., Karasev, A., Kuznetsov, D. & Jönsson, P. (2019). Modification of Non-Metallic Inclusions in Oil-Pipeline Steels by Ca-Treatment. METALS, 9(4), Article ID 391.
Open this publication in new window or tab >>Modification of Non-Metallic Inclusions in Oil-Pipeline Steels by Ca-Treatment
2019 (English)In: METALS, ISSN 2075-4701, Vol. 9, no 4, article id 391Article in journal (Refereed) Published
Abstract [en]

Corrosion rate in different steel grades (including oilfield pipeline steels) is determined by the presence of non-metallic inclusions (NMI) in steels. Specifically, the effect of different inclusions on the quality of steels depends on their characteristics such as size, number, morphology, composition, and physical properties, as well as their location in the steel matrix. Therefore, the optimization and control of NMI in steels are very important today to obtain an improvement of the material properties of the final steel products. It is well known that a Ca-treatment of liquid steels in ladle before casting is an effective method for modification of non-metallic inclusions for improvement of the steel properties. Therefore, the NMI characteristics were evaluated in industrial steel samples of low carbon Ca-treated steel used for production of oil-pipelines. An electrolytic extraction technique was used for extraction of NMI from the steel samples followed by three-dimensional investigations of different inclusions and clusters by using SEM in combination with EDS. Moreover, the number and compositions of corrosion active non-metallic inclusions were estimated in hot rolled steel samples from two different heats. Finally, the corrosion resistance of these steels can be discussed depending on the characteristics of non-metallic inclusions present in the steel.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
oil-pipeline steel, Ca-treatment, non-metallic inclusions, electrolytic extraction, corrosion
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-252645 (URN)10.3390/met9040391 (DOI)000467637000008 ()2-s2.0-85064179266 (Scopus ID)
Note

QC 20190610

Available from: 2019-06-10 Created: 2019-06-10 Last updated: 2019-06-10Bibliographically approved
Du, H., Karasev, A., Sundqvist, O. & Jönsson, P. (2019). Modification of Non-Metallic Inclusions in Stainless Steel by Addition of CaSi. METALS, 9(1), Article ID 74.
Open this publication in new window or tab >>Modification of Non-Metallic Inclusions in Stainless Steel by Addition of CaSi
2019 (English)In: METALS, ISSN 2075-4701, Vol. 9, no 1, article id 74Article in journal (Refereed) Published
Abstract [en]

The focus of this study involved comparative investigations of non-metallic inclusions in 316L stainless steel bars without and with Ca treatments. The inclusions were extracted by using electrolytic extraction (EE). After that, the characteristics of the inclusions, such as morphology, size, number, and composition, were investigated by using a scanning electron microscope (SEM) in combination with an energy dispersive X-ray spectroscopy (EDS). The following four types of inclusions were observed in 316L steels: (1) Elongated MnS (Type I), (2) MnS with hard oxide cores (Type II), (3) Undeformed irregular oxides (Type III), and (4) Elongated oxides with a hard oxide core (Type IV). In the reference sample, only a small amount of the Type III oxides (Al2O3-MgO-MnO-TiOx) existed. However, in Ca-treated 316L steel, about 46% of the observed inclusions were oxide inclusions (Types III and IV) correlated to gehlenite and to a mixture of gehlenite and anorthite, which are favorable for the machinability of steel. Furthermore, untransformed oxide cores (Al2O3-MgO-MnO) were also found in the inclusions of Type IV. The mechanism leading to different morphologies of oxide inclusions is also discussed.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
stainless steel, Ca treatment, non-metallic inclusion, electrolytic extraction
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-246294 (URN)10.3390/met9010074 (DOI)000459738500073 ()2-s2.0-85060092047 (Scopus ID)
Note

QC 20190325

Available from: 2019-03-25 Created: 2019-03-25 Last updated: 2019-03-25Bibliographically approved
Nabeel, M., Alba, M., Sun, S., Karasev, A., Jönsson, P. & Dogan, N. (2018). Characterization of inclusions in high-Mn steel using two-dimensional and three-dimensional methods. In: AISTech - Iron and Steel Technology Conference Proceedings: . Paper presented at AISTech 2018 Iron and Steel Technology Conference and Exposition, 7 May 2018 through 10 May 2018 (pp. 1483-1491). Association for Iron and Steel Technology, AISTECH
Open this publication in new window or tab >>Characterization of inclusions in high-Mn steel using two-dimensional and three-dimensional methods
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2018 (English)In: AISTech - Iron and Steel Technology Conference Proceedings, Association for Iron and Steel Technology, AISTECH , 2018, p. 1483-1491Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Association for Iron and Steel Technology, AISTECH, 2018
Keywords
Automated SEM, Electrolytic extraction, High manganese, Inclusions
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-247402 (URN)2-s2.0-85062522160 (Scopus ID)9781935117728 (ISBN)
Conference
AISTech 2018 Iron and Steel Technology Conference and Exposition, 7 May 2018 through 10 May 2018
Note

QC20190418

Available from: 2019-04-18 Created: 2019-04-18 Last updated: 2019-04-18Bibliographically approved
Al-Saadi, M., Karasev, A., Jönsson, P. & Sandberg, F. (2018). Comparative Study of Microstructures Evolution of Columnar and Equiaxed Grain Structurs in Alloy 825 after Hot Compression. In: 3rd InternationalConference on Ingot Casting, Rolling and Forging, ICRF2018, in Stockholm, 16-19October: . Paper presented at 3rd International Conference on Ingot Casting, Rolling and Forging, ICRF2018, in Stockholm, 16-19 October. , Article ID 114.
Open this publication in new window or tab >>Comparative Study of Microstructures Evolution of Columnar and Equiaxed Grain Structurs in Alloy 825 after Hot Compression
2018 (English)In: 3rd InternationalConference on Ingot Casting, Rolling and Forging, ICRF2018, in Stockholm, 16-19October, 2018, article id 114Conference paper, Published paper (Refereed)
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:kth:diva-235343 (URN)
Conference
3rd International Conference on Ingot Casting, Rolling and Forging, ICRF2018, in Stockholm, 16-19 October
Note

QCR 20181008

Available from: 2018-09-21 Created: 2018-09-21 Last updated: 2018-10-08Bibliographically approved
Al-Saadi, M., Jönsson, P., Sandberg, F., Karasev, A. & Jonsson, S. (2018). Microstructure characterisation in alloy 825. In: : . Paper presented at 17th International Conference on Metal Forming, Metal Forming 2018, 16-19 September 2018, Toyohashi, Japan (pp. 1626-1634). , 15
Open this publication in new window or tab >>Microstructure characterisation in alloy 825
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2018 (English)Conference paper, Published paper (Refereed)
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:kth:diva-234261 (URN)10.1016/j.promfg.2018.07.294 (DOI)2-s2.0-85063780828 (Scopus ID)
Conference
17th International Conference on Metal Forming, Metal Forming 2018, 16-19 September 2018, Toyohashi, Japan
Note

QC 20180906

Available from: 2018-09-05 Created: 2018-09-05 Last updated: 2019-05-16Bibliographically approved
Yoshioka, T., Ideguchi, T., Karasev, A., Ohba, Y. & Jönsson, P. G. (2018). The Effect of a High Al Content on the Variation of the Total Oxygen Content in the Steel Melt during a Secondary Refining Process. Steel Research International, 89(2), Article ID 1700287.
Open this publication in new window or tab >>The Effect of a High Al Content on the Variation of the Total Oxygen Content in the Steel Melt during a Secondary Refining Process
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2018 (English)In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 89, no 2, article id 1700287Article in journal (Refereed) Published
Abstract [en]

The aim of this study is to clarify the mechanism of low total oxygen (T.O) contents in high-Al containing steel grades. Steel samples are taken from a ladle during an LF-RH process, and the compositions of both the steels and inclusions are determined. According to thermodynamic considerations, the low T.O contents of high Al steel grades are due to the low insoluble oxygen contents. Due to the high Al contents in a steel melt, thermodynamic driving forces of the Al2O3 modification are lower than those in ordinary Al-killed steels. Both the low thermodynamic driving force of the Al2O3 modification and the inclusion removal from the melts contribute to the low CaO contents in inclusions in high-Al steel melts. The contact angles of inclusions in high Al steel melts are higher than 90 degrees due to the low CaO content in inclusions. Therefore, the removal tendency of inclusions in high Al steel melts is kept high throughout an LF-RH process. Due to this high removal tendency, the T.O contents in high Al steel melts decreases remarkably during an LF refining process. Thereafter, they decrease further during the following RH treatment.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2018
Keywords
contact angle, high Al, inclusion evolution, inclusion removal, thermodynamics
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-223274 (URN)10.1002/srin.201700287 (DOI)000423833200011 ()2-s2.0-85028726650 (Scopus ID)
Note

QC 20180216

Available from: 2018-02-16 Created: 2018-02-16 Last updated: 2018-05-14Bibliographically approved
Kellner, H. E. O., Karasev, A., Sundqvist, O., Memarpour, A. & Jönsson, P. (2017). Estimation of Non-Metallic Inclusions in Industrial Ni Based Alloys 825. Steel Research International, 88(4), Article ID UNSP 1600024.
Open this publication in new window or tab >>Estimation of Non-Metallic Inclusions in Industrial Ni Based Alloys 825
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2017 (English)In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 88, no 4, article id UNSP 1600024Article in journal (Refereed) Published
Abstract [en]

It is well known that inclusions affect the properties of the steel and other alloys. The importance of understanding the behavior of the inclusions during production can never be overstated. This study has examined the main types of big size (> 10 mu m) inclusions that exist in Ni-based Alloy at the end of ladle treatment and after casting during industrial production of Ni based Alloys 825. Sources, mechanisms of formation and behavior of different type large size inclusions in Alloy 825 are discussed based on 2 and 3D investigations of inclusion characteristics (such as, morphology, composition, size, and number) and thermodynamic considerations. The large size inclusions found can be divided in spherical (Type I and II) inclusions and in clusters (Type III-V). Type I-A inclusions (Al2O3-CaO-MgO) originate from the slag. Type I-B inclusions and Type II inclusions consist of CaO-Al2O3-MgO and Al2O3-TiO2-CaO, respectively. Both types originate from the FeTi70R alloy. Type III clusters (Al2O3-MgO-CaO) are formed during an Al deoxidation of the Ni-based alloy. Type IV clusters (Al2O3-TiO2-CaO) formed from small inclusions, which are precipitated in local zones which contain high Ti and Al levels. These clusters are transformed to Type III clusters over time in the ladle. Finally, Type V clusters are typical TiN clusters.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2017
Keywords
Alloy 825, inclusion distribution, non-metallic inclusions
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-206287 (URN)10.1002/srin.201600024 (DOI)000398639200012 ()2-s2.0-85014553773 (Scopus ID)
Note

QC 20170509

Available from: 2017-05-09 Created: 2017-05-09 Last updated: 2017-11-22Bibliographically approved
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