Interpretation of nature of non-metallic inclusions in assessing the quality of metal products in the industrial conditions

Kazakov, A. A.; Murysev, V. A.; Kiselev, D. V.

doi:10.17580/chm.2021.09.08

Cited by 7 publications

(7 citation statements)

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“…It follows from the Table 1, that slags and refractory materials do not serve as a source of sulfur in non-metallic inclusions, so CaS in their composition should be definitely related to products of steel modification by calcium. The authors of publications [5][6][7][8][9][10][18][19][20] have the same opinion, however, several of them [6][7][8][9] have wrongly associated the origin of CaO and Al 2 O 3 in the inclusions found in discontinuities of defects, with exogenous particles of slag. It is impossible to agree with this, since all the slags used during secondary steelmaking and casting still include SiO 2 , especially in the tundish and mould, where its concentration, calculated on the silicon content, reaches 30% (Table 1).…”

Section: Sources Of Exogenous Non-metallic Inclusionsmentioning

confidence: 99%

“…Earlier, we developed a "cluster" technique for interpretation of composition of nonmetallic inclusions found in discontinuities of HFIW welds, which allowed us to summarize many years of factory experience in studying these defects in steels 09G2S [19] and 22GYu [20]. Compositions of NMIs calculated by thermodynamic simulation were combined into the first type of clusters of indigenous deoxidation and modification products.…”

Section: Introductionmentioning

confidence: 99%

“…Summarizing more than 400 compositions of inclusions found mainly in the hook cracks of welded joints, it is proved that they are conglomerates consisting of deoxidation products absorbed on the surface of the refractories of metal wiring. These conglomerates, separated by the onset flow of steel melt from the surface of refractories together with the particles of these refractories, get into the mould, also after the interaction with its slag [19][20]. Such coarse conglomerates cannot penetrate deeply into the solidifying slab, so after its rolling they all find themselves at the edges of the sheet.…”

Section: Introductionmentioning

confidence: 99%

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Non-metallic inclusions and hook cracks of high-frequency induction welded pipes

Kazakov¹,

Kiselev²,

Murysev³

et al. 2022

cisisr

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Based on the analysis of foreign experience, it is shown that hook cracks are the most common defect of pipe joints obtained by high-frequency induction welding (HFIW). Particular attention is paid to the non-metallic inclusions (NMIs) that caused this defect. Their composition, origin and ways of elimination are considered. It was found that in the foreign literature the nature of certain oxides found in the vicinity of defects is often declared without objective evidence of their origin. The interpretation technique of NMIs composition, which caused the formation of defects of pipe joints obtained by HFIW, is presented. This technique is a part of the "Metal products quality system", implemented on the basis of Thixomet image analyzer, working in the laboratories of Vyksa Steel Works JSC. The compositions of NMIs found in the discontinuities of welded joint defects of 09G2S steel grade were interpreted using thermodynamic simulation of primary NMIs and generalized for two sets of 65 and 70 defects in each set. These compositions differ significantly from each other and correspond to the following indigenous inclusions: Al 2 O 3 , MgO•Al 2 O 3 , calcium aluminates, CaO and CaS. The same compounds can form exo-indigenous NMIs conglomerates after the interaction between liquid calcium aluminates and refractories based on MgO or ZrO 2 , and/or mould powder. The unique ranges of concentration changes of the main elements included in individual phases and their combinations in NMIs conglomerates are used for automated determination of their origin when conducting metallographic examination of defects using the Thixomet image analyzer. Examples of using the origin of NMIs to find the exact place in the secondary steelmaking and steel casting technologies for their improvement and on this basis to improve the quality of HFIW pipe joints are also presented.

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Section: Sources Of Exogenous Non-metallic Inclusionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Non-metallic inclusions and hook cracks of high-frequency induction welded pipes

Kazakov¹,

Kiselev²,

Murysev³

et al. 2022

cisisr

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“…To summarize the chemical compositions of the nonmetallic inclusions found in the vicinity of the defects, on the one hand, and the indigenous inclusions found by thermodynamic simulation, on the other hand, we calculated clusters combining similar compositions in each of these two groups of NMIs [13].…”

Section: Cluster Analysis and Interpretation Of Non-metallic Inclusionsmentioning

confidence: 99%

Non-metallic inclusions interpretation technique for factory expertise of metal product defects

Kazakov¹,

Murysev²,

Kiselev³

2021

cisisr

Self Cite

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“…It is known from the work of present-day researchers that segregation heterogeneity in finished rolled products can be manifested in the form of axial central segregation heterogeneity, which is a consequence of axial chemical heterogeneity, as well as the axial discontinuity of a continuously cast billet [15]. The degree of the segregation band development in the structure of rolled products depends both on the concentration of highly segregating elements such as sulfur, phosphorus, carbon, non-ferrous metal impurities, a number of alloying elements, and on the crystallization conditions, as well as the solidification parameters of the continuously cast billet [16,17]. Rolled sheets and coils with a pronounced segregation band are characterized by an increased tendency towards defect formation, including internal delamination with the formation of cracks directed along the interface between the segregation band and the base metal.…”

Section: Introductionmentioning

confidence: 99%

Structural Anisotropy Parameters’ Effect on the Low-Temperature Impact Strength of Alloy Steels in Rolled Products

Kovalyova

Issagulov

Kovalev

et al. 2023

Metals

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The present work is devoted to the study of the influence of the parameters of the structural anisotropy of rolled products on the low-temperature impact strength of alloyed steels. A quantitative metallographic analysis of the microstructure of rolled steel samples obtained after testing for low-temperature toughness was carried out. It was established that the main reason for the decrease in the low-temperature impact strength of rolled steel samples is a highly developed segregation band enriched with carbon films formed at the stage of steelmaking conversion in violation of the technology of continuous casting of steel. The microstructural analysis of rolled stock samples was used in the work, and studies of the fracture surface of rolled stock samples were carried out with a scanning electron microscope using X-ray microanalysis methods. The studies carried out showed that the metallurgical quality of sheets of one heat, as well as individual samples within one sheet, varied over a wide range, from satisfactory to unacceptably low. It was established that the main reason for the decreasing low-temperature impact strength of rolled products was a highly developed segregation band enriched with carbon films, formed at the stage of steelmaking in case of violation of the continuous casting of steel technology. The multivariate statistical analysis carried out showed that only the size of the segregation band has an effect on the low-temperature impact strength of 10 mm thick rolled coil samples.

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Interpretation of nature of non-metallic inclusions in assessing the quality of metal products in the industrial conditions

Cited by 7 publications

References 0 publications

Non-metallic inclusions and hook cracks of high-frequency induction welded pipes

Non-metallic inclusions and hook cracks of high-frequency induction welded pipes

Non-metallic inclusions interpretation technique for factory expertise of metal product defects

Structural Anisotropy Parameters’ Effect on the Low-Temperature Impact Strength of Alloy Steels in Rolled Products

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