Benetzbarkeit von festen CaO-MgO-SiO2
 - und Al2
O3
-SiO2
-CaO-Oxiden durch flüssigen Stahl

Staronka, Andrzej; Gołas, Wojciech

doi:10.1002/srin.198004863

Cited by 4 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Refractory erosion of the ladle and metal delivery system introduce inclusions that can impair the quality of what was otherwise very clean refined steel. 3,9,[13][14][15][16][17][18] In addition, air entrainment 8,19) during teeming generates reoxidation inclusions, such as alumina clusters in Al-killed steels, and the turbulent flow and mixing with the teeming flux during the initial entry of steel into the mold can induce flux entrainment [20][21][22][23][24][25][26]27) during solidification. Inclusion distribution in an ingot is affected by fluid flow, heat transfer and solidification of the steel.…”

Section: Introduction and Methodologymentioning

confidence: 99%

Large Inclusions in Plain-carbon Steel Ingots Cast by Bottom Teeming

et al. 2006

View full text Add to dashboard Cite

Inclusions in industrial-cast bottom-teemed ingots of plain carbon steel are investigated using ultrasonic detection, optical microscope observation, and SEM analysis. The composition, size distribution, entrapment locations, and sources of ingot inclusions were revealed by examining all the macro-inclusions (larger than 20 mm) that were observed in 35 000 mm 2 of sample surface area. Based on 78 non-sulfide inclusions observed, around 3.23ϫ10 7 macro-inclusions per m 3 steel exist in the ingot, with a size distribution increasing with decreasing size. Inclusions are distributed uniformly within a given horizontal section through the ingot, but with more found towards the bottom. The largest inclusions exceed 7 mm and originate from mold flux in the ingot. The largest inclusion source appears to be reoxidation, as evidenced by 59% of the ingot inclusions composed of pure alumina clusters and lumps. Eroded refractories from the ladle well block and ladle inner nozzle bricks accounted for 31% of the ingot inclusions.KEY WORDS: steel ingot; inclusions; mold flux; alumina; exogenous inclusions.portion, due to the mechanism of positive segregation.29) It should be noticed that most of these papers on inclusions in steel ingots were published before 1990s, and very few are published in recent 15 years.This current work is part of a larger project to investigate inclusions in bottom-teemed steel ingots by combining computational models and plant experiments conducted at member companies of the Ingot Metallurgy Forum. A survey with responses from six steel ingot producers in the US revealed that the total annual tonnage of bottom-poured ingots where cleanliness is a concern is at least 700 000 tons. Rejections at these companies due to inclusion defects range from 0.2-5 % with a cost of $900-3 600/tonne (depending on grade). This corresponds to $10 million per year (assuming a typical rejection rate of 1 % at $1 500/ ton). From the survey replies, 10-25 % of defects sources are estimated to be related to ladle sand/packing sand entrapment, 25-50 from mold flux entrainment, 0-5 % from runner erosion, and 0-35 % related to other exogenous inclusion sources. In addition to the above exogenous inclusion sources, the companies estimated that 0-15 % of their defects were from alumina inclusions (deoxidation products), 0-20 % from air absorption, 0-5 % from reoxidation reactions with slag and refractory, and 0-10 % from unknown sources. Clearly, exogenous defects are the greatest problem. The actual amount and nature of these inclusion sources is investigated in the present work, based on industrial trials conducted at Ellwood Quality Steels Co. Process Description and MethodologyThis work investigates large inclusions measured in a bottom-teemed ingot of 1022 carbon steel, with a composition (ladle analysis) shown in Table 1.The ingot production process of concern is shown Fig. 1 and is described as follows:Step 1: Scrap is loaded into clam-shell buckets and charged into an ultra high powered (UHP) eccentric bottom tapping (E...

show abstract

Section: Introduction and Methodologymentioning

confidence: 99%

Large Inclusions in Plain-carbon Steel Ingots Cast by Bottom Teeming

et al. 2006

View full text Add to dashboard Cite

show abstract

“…The slight decrease in q at 1% glass fiber added may be explained as being due to the insufficient amount of liquid glass. It was reported in [18,21] that the angle q at contact steel + SiO 2 was 112°. Our results for angle q in the contact zone steel -MgO + 2 or 8% glass fiber were 113 and 111°, respectively.…”

Section: Additive To Glass Fiber Substratementioning

confidence: 98%

Wettability of tundish periclase lining by steel

et al. 2006

View full text Add to dashboard Cite

Results of a study of the wettability of the tundish periclase lining by molten steel using a sessile drop method are presented. The wetting angle q tends to decrease with increase in temperature and contact time on adding glass fiber and Fe 2 O 3 powder in excess of 2% to the magnesite powder; a similar effect is observed in steels high in manganese. An increase in angle q is observed on adding carbon fiber or glass fiber (not in excess of 1%) to the magnesite powder; the angle q tends to increase with increase in MgO powder grain size and with carbon contained in steel in excess of 0.04%.In recent years, there has been an increased demand for steels with a low impurity content. Technologically, the tundish ladle is the last refractory-lined vessel in which the molten steel is processed metallurgically before pouring into molds. MgO-based refractory materials are preferred for making the hot layer of the refractory lining of the tundish ladle. To increase the strength of the lining (normally applied using a gunning technique), additives are introduced into the gunning mix -paper fiber (coarse-or fine-fibrous), mineral wool, glass fiber, expandable clay, and polystyrene beads [1 -3].The interaction between tundish lining and molten steel and slag is an important concern for manufacturing high-purity steels. This interaction involves two related phenomena: wetting and reaction between the three components, which determines the service life of the refractory and the properties of molded preforms, slabs, and blooms [4,5]. To determine the wettability of a solid substrate by molten metal, Young's equation is conventionally used [6]:where q is the wetting angle, deg; g SV is the surface tension of the solid; g SL is the energy of surface interaction between the liquid and the solid; g LV is the surface tension of the liquid. As is known, the liquid wets the solid if q < 90°; in unwettable systems, it is q > 90°.Data have been reported on the wettability of various refractory surfaces [7 -21] by molten iron and steel [7 -9] and on their interaction with gas media [7 -9, 11, 21] and molten slag [7 -9].In [13 -16], the wettability of aluminosilicate refractories by steel or iron was studied; in [17], the effect of Steel 35 on corundum composites was studied, and in [20], the wetting angle q at zirconium surfaces and molten iron was measured. MgO is the most widely used material for manufacturing the tundish lining; still, data on the wettability of periclase lining by molten steel and the effect of additives on wettability are sadly lacking [7,22]. Therefore our goal in this work was to study the wettability of MgO by molten steel. EXPERIMENTALThe low-carbon steels were made available from the Eregli Iron and Steel Works (Turkey); their composition is given in Table 1. The tests were carried out by a sessile drop method; the test specimens were cubes of steel weighing about 0.3 g; the substrate was a magnesite powder of composition, wt.%: MgO, 95.08; SiO 2 , 2.49; CaO, 1.73; Fe 2 O 3 , 0.54; Al 2 O 3 , 0.16. The powde...

show abstract

“…[172,173,174] Without mold powder, an oxide scum forms on the surface of the metal as it rises in the mold. This is more prominent in steels containing aluminum and titanium, where the scum formed is heavy and viscous.…”

Section: B Slag Entrainment Mechanismsmentioning

confidence: 99%

State of the art in the control of inclusions during steel ingot casting

Zhang

Thomas

2006

Metall Mater Trans B

244

129

View full text Add to dashboard Cite

This article extensively reviews published research on inclusions in ingot steel and defects on ingot products, methods to measure and detect inclusions in steel, the causes of exogenous inclusions, and the transport and entrapment of inclusions during fluid flow, segregation, and solidification of steel cast in ingot molds. Exogenous inclusions in ingots originate mainly from reoxidation of the molten steel, slag entrapment, and lining erosion, which are detailed in this article. The measures to prevent the formation of exogenous inclusions and improve their removal are provided, which are very useful for the clean steel production of ingot industries.

show abstract

Benetzbarkeit von festen CaO-MgO-SiO₂ - und Al₂ O₃ -SiO₂ -CaO-Oxiden durch flüssigen Stahl

Cited by 4 publications

References 0 publications

Large Inclusions in Plain-carbon Steel Ingots Cast by Bottom Teeming

Large Inclusions in Plain-carbon Steel Ingots Cast by Bottom Teeming

Wettability of tundish periclase lining by steel

State of the art in the control of inclusions during steel ingot casting

Contact Info

Product

Resources

About

Benetzbarkeit von festen CaO-MgO-SiO2 - und Al2 O3 -SiO2 -CaO-Oxiden durch flüssigen Stahl

Cited by 4 publications

References 0 publications

Large Inclusions in Plain-carbon Steel Ingots Cast by Bottom Teeming

Large Inclusions in Plain-carbon Steel Ingots Cast by Bottom Teeming

Wettability of tundish periclase lining by steel

State of the art in the control of inclusions during steel ingot casting

Contact Info

Product

Resources

About

Benetzbarkeit von festen CaO-MgO-SiO₂ - und Al₂ O₃ -SiO₂ -CaO-Oxiden durch flüssigen Stahl