scholarly journals Effect of Zr Additions on Non-Metallic Inclusions in X11CrNiMo12 Steel

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1183
Author(s):  
Jaka Burja ◽  
Mitja Koležnik ◽  
Barbara Šetina Batič ◽  
Jožef Medved
Keyword(s):  
Martensitic Steel ◽  
Inclusion Size ◽  
Reaction Products ◽  
Clean Steel ◽  
Metallic Inclusions ◽  
Inclusion Modification ◽  
Steel Cleanliness ◽  
Steel Grades ◽  
Al Additions ◽  
Deoxidation Practice

The production of clean steel is associated with high-quality steel grades for demanding applications. The formation of oxide inclusions mainly depends on the deoxidation practice; it is usually carried out through Al additions, but alumina inclusions can have detrimental effects. An alternative zirconium inclusion modification was used in a creep-resistant steel to improve the cleanliness of laboratory-made steel. The thermodynamics behind the inclusion modification are presented, the reaction products are identified and the steel cleanliness improvement is quantified. The resulting influence of zirconium addition on non-metallic inclusions and mechanical properties is discussed. While the Zr additions drastically reduce the non-metallic inclusion size and area, additions above a certain amount result in the formation of zirconium nitrides that ultimately soften the martensitic steel due to the depletion of nitrogen in solid solution.

Effect of CaO–SiO2–Al2O3–MgO top slag on solute elements and non-metallic inclusions in Fe-xMn(x = 10, 20 mass pct) steel

2021 ◽  
Vol 118 (3) ◽  
pp. 302
Author(s):  
Huixiang Yu ◽  
Dexin Yang ◽  
Muming Li ◽  
Ni Zhang
Keyword(s):  
Reaction System ◽  
Manganese Steel ◽  
High Manganese ◽  
Precise Control ◽  
Metallic Inclusions ◽  
Steel Cleanliness ◽  
Steel Grades ◽  
High Manganese Steels ◽  
Manganese Steels ◽  
Top Slag

Medium/high manganese steels have broad application prospects in automotive industry, cryogenic material, etc. because of excellent properties. Precise control on steel composition and improvement of cleanliness are very important for commercial production of these steel grades. In this study, the effect of CaO–SiO2–Al2O3–MgO slag on solute elements and inclusions of Fe-xMn(x = 10, 20 mass pct) steel was studied and discussed. After slag/steel reaction, the concentration of Mn and S in steel reduced, while Si increased. Most MnO type inclusions, which were the main inclusions in master high manganese steel, transformed to MnO–SiO2 type and MnO–Al2O3–MgO type, with MnO–SiO2 sharing the majority. Thermodynamic analysis indicates that the change of solute elements and inclusions was mainly the result of reaction SiO2(s) + 2[Mn] = 2MnO(s) + [Si] between molten steel and top slag as well as slag desulphurization. Increase of oxygen potential of the reaction system would restrain the reaction. Because of the inclusion absorption by top slag, large sized inclusions decreased and steel cleanliness improved greatly after CaO–SiO2–Al2O3–MgO slag was added.

The effects of morphology of ferrite and non-metallic inclusions on corrosion behaviour of as-cast 304 stainless steel

CORROSION ◽  
10.5006/3763 ◽  
2021 ◽  
Author(s):  
Danbin Jia ◽  
Liangcai Zhong ◽  
Jingkun Yu ◽  
Zhaoyang Liu ◽  
Yuting Zhou ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Corrosion Behaviour ◽  
Solidification Process ◽  
Inclusion Size ◽  
304 Stainless Steel ◽  
Experimental Conditions ◽  
Quenching Temperature ◽  
Δ Ferrite ◽  
Metallic Inclusions

The effects of morphology of ferrite and non-metallic inclusions on corrosion resistance of as-cast 304 stainless steel (304 SS) were investigated. With the decrease in quenching temperature from 1723 K to 1648 K, the different microstructures of the as-cast 304 SS were obtained as the following series: austenitic-lathy δ ferrite, austenitic-colony δ ferrite and austenitic-blocky δ ferrite, and the average inclusion size increased. The electrochemical results show that the sample with the microstructure of austenitic- lathy δ ferrite and smaller size inclusions had a higher corrosion tendency and the lower pitting resistance. Furthermore, the effect of morphology and content of ferrite on corrosion resistance was greater than that of inclusion size under the current experimental conditions. Therefore, a promising method was developed to improve the corrosion resistance of as-cast 304 SS by changing the solidification process.

scholarly journals Study of the Influence of Intermix Conditions on Steel Cleanliness

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 852 ◽  
Author(s):  
Branislav Bul’ko ◽  
Marek Molnár ◽  
Peter Demeter ◽  
Dana Baricová ◽  
Alena Pribulová ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Negative Impact ◽  
Cast Steel ◽  
Continuous Casting Machine ◽  
Casting Machine ◽  
Chemical Compositions ◽  
Negative Effect ◽  
Type Size ◽  
Steel Cleanliness ◽  
Steel Grades

Modern steel plants produce today a large portfolio of various steel grades, many for end-uses demanding high quality. In order to utilize the maximum productivity of the continuous-casting machine, it is sometimes necessary to cast steel grades with different chemical compositions in one sequence. It is important, therefore, to know the possibilities of a specific continuous-casting machine to make the Intermix connections as short as possible. Any interference with established procedures may, however, have a negative impact on the cleanliness of the cast steel. Using physical and numerical simulation tools, it was found that reducing the steel level in the tundish during the exchange of ladles makes it possible to shorten the transition zone. However, when the steel level is reduced, the flow of steel is impaired, which can have a negative effect on the cleanliness of the cast steel and, in extreme cases, may even lead to entrapment of slag in the mold. The cleanliness of cast steel was evaluated using one of the most advanced tools for automatic steel cleanliness evaluation, AZtecFeature (Oxford Instruments, Abingdon, UK), which enables determination of the type, size, distribution, and shape, as well as the chemical composition, of individual types of non-metal inclusions.

Characterization of Non-Metallic Inclusions in API Steel Grades Using Automated Energy Dispersive X-Ray

2018 ◽  
Vol 916 ◽  
pp. 217-220
Author(s):  
Masoud Al-Gahtani ◽  
Sunilkumar Pillai ◽  
Ahmad Al-Raddadi
Keyword(s):  
Inclusion Composition ◽  
X Ray ◽  
Steel Making ◽  
Metallic Inclusions ◽  
Hydrogen Induced Cracking ◽  
Steel Processing ◽  
Steel Grades ◽  
Formation And Evolution ◽  
Scanning Electron

Non-metallic inclusions in API steel grades deteriorate steels’ mechanical properties and their resistance to hydrogen induced cracking. The formation and evolution of inclusion during liquid steel processing was investigated by analyzing samples taken from different stages of the steel making process in API X52 and X60 steel grades. Scanning electron microscope (SEM) with automated feature EDX analyzer (INCAF 250) was used to identify each inclusion in terms of its size, area and composition. It was found that non-metallic inclusions in API X52 and X60 grades from steelmaking and casting samples were mainly Al2O3, Ca–Al and Ca-Mg-Al. In this work changes in inclusion composition, size and area fraction from ladle processing to casting were mapped and this information was used to improve steel cleanness and product quality.

Evaluation of Inclusions in P/M Superalloy

2013 ◽  
Vol 747-748 ◽  
pp. 513-517 ◽  
Author(s):  
Hua Yuan ◽  
Zhou Li ◽  
Guo Qing Zhang ◽  
Wen Yong Xu ◽  
Na Liu
Keyword(s):  
Master Alloy ◽  
Inclusion Size ◽  
Metallic Inclusions ◽  
Powder Billet

The non-metallic inclusions in master alloy, P/M superalloy and HIP powder billet were studied in this paper. The results show that the amount of inclusions in master alloy is higher than that of the superalloy powers. The EB-button analysis shows that the main non-metallic inclusions in both the master alloy and the HIP powder billet is Al2O3.The amount of the inclusion in master alloy is about 0.166cm2/kg and the size of most inclusions is in the range of 100μm to 200μm, while the maximum inclusion size reaches 400μm.In the P/M superalloy billet, the content of inclusion is only 0.01cm2/kg and the size of most inclusions is less than 50 μm.

Effect of Non-Metallic Inclusions on Notched Low Cycle Fatigue in P/M IN100 Nickel-Base Superalloy

2007 ◽  
Vol 539-543 ◽  
pp. 2960-2965
Author(s):  
Agnieszka M. Wusatowska-Sarnek ◽  
P. Bhowal ◽  
Daniel Gynther ◽  
Rick Montero
Keyword(s):  
Low Cycle Fatigue ◽  
Notch Root ◽  
Stress Gradient ◽  
Inclusion Size ◽  
Critical Conditions ◽  
Nickel Base Superalloy ◽  
Cycle Fatigue ◽  
Metallic Inclusions ◽  
Nickel Base ◽  
Applied Stresses

The notched low cycle fatigue (LCF) behavior of a P/M (Powder Metallurgy) gas turbine disk superalloy (IN100) was investigated to determine the role of inclusions, such as oxides, that are intrinsic in the process of making powder superalloys. Tests were carried out at temperatures ranging from 426°C to 621°C at several applied stresses. The majority of LCF failures initiated from inclusions (oxides) with minority initiation sites being grain facet in the microstructure. The locations of initiation sites were surface or subsurface, and reduced LCF life was generally associated with surface initiation at the notch root. However, surface initiation was infrequent and observed only at high stresses (i.e., in the presence of large plasticity at the notch root). The stress gradient at the notch root coupled with inclusion size determined the critical conditions for fatigue initiation. In the present paper, these failures and the associated LCF life are discussed in terms of inclusion size and its proximity to the notch root.

scholarly journals Evolution of Non-Metallic Inclusions in Secondary Steelmaking: Learning from Inclusion Size Distributions

2013 ◽  
Vol 53 (11) ◽  
pp. 1974-1982 ◽  
Author(s):  
Marie-Aline Van Ende ◽  
Muxing Guo ◽  
Enno Zinngrebe ◽  
Bart Blanpain ◽  
In-Ho Jung
Keyword(s):  
Inclusion Size ◽  
Size Distributions ◽  
Metallic Inclusions ◽  
Secondary Steelmaking

Analyzing the Features of Non-Metallic Inclusion Distribution in Ø410 mm Continuously Cast Billets of Low Carbon Steel Grades

2019 ◽  
Vol 973 ◽  
pp. 21-25
Author(s):  
Mikhail Y. Chubukov ◽  
Dmitriy V. Rutskiy ◽  
Dmitriy P. Uskov
Keyword(s):  
Low Carbon Steel ◽  
Low Carbon ◽  
Metallic Inclusion ◽  
Peritectic Steel ◽  
Cross Section Area ◽  
Section Area ◽  
Metallic Inclusions ◽  
Steel Grades ◽  
Continuously Cast ◽  
Inclusion Distribution

The paper reports findings on the morphology of non-metallic inclusions in low carbon pre-peritectic and peritectic steel grades used for the fabrication of seamless pipes. It is demonstrated that the distribution of non-metallic inclusions over the cross section area of continuously cast billets is of a step-like nature conditioned by the features of billet solidification. In all the steels analyzed the non-metallic inclusions are presented by oxides, sulfides and complex oxi-sulfides not larger than 2 μm.

scholarly journals Evolution of non-metallic inclusions during heat treatment

2020 ◽  
Vol 117 (4) ◽  
pp. 408
Author(s):  
Chengsong Liu ◽  
Bryan Webler
Keyword(s):  
Heat Treatment ◽  
Size Distribution ◽  
Inclusion Size ◽  
Isothermal Heat Treatment ◽  
Number Density ◽  
Inclusion Composition ◽  
Steel Microstructure ◽  
Metallic Inclusions ◽  
Higher Temperature ◽  
Average Size

Isothermal heat treatment can not only modify steel microstructure, but also non-metallic inclusions. In this work, heat treatment experiments were conducted between 1373 and 1573 K (1100 and 1300 °C) to study the evolution of inclusion composition, morphology, and size distribution. Results showed that during the heat treatment at 1473 and 1573 K (1200 and 1300 °C), two main kinds of inclusions initially in the steel, CaS and MgO–Al2O3–CaO–CaS, gradually transformed to (Ca, Mn)S and MgO–Al2O3–(Ca, Mn)S inclusions, and some MgO–Al2O3–CaO inclusions also transformed to MgO–Al2O3–(Ca, Mn)S. At the lowest temperature studied, 1373 K (1100 °C), little change was observed. No significant changes in number density and area fraction of the measured inclusions were observed, while the average size of inclusions increased after the heat treatment. The extent of transformation of CaS, MgO–Al2O3–CaO–CaS and MgO–Al2O3–CaO inclusions increased with decreasing inclusion size and higher temperature.

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