Influence of Ti and REE on Primary Crystallization and Wear Resistance of Chromium Cast Iron

Dojka, Malwina; Dojka, Rafał; Stawarz, M.; Studnicki, A.

doi:10.1007/s11665-019-04088-x

Cited by 11 publications

(17 citation statements)

References 18 publications

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“…The source literature explains the existing research outlook regarding the modification of chromium cast iron [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. A large number of publications describe the effects of nucleogenic elements after their addition to liquid metal, typically in the form of ferroalloys, which stimulate the creation of hard-to-melt compounds as crystallization underlays for primary austenite and chromium carbides (inoculation process), depending on the selected cast iron chemical composition [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. Their use increases the number of eutectic colonies in the microstructure, with carbides featuring more favorable morphologies.…”

Section: Introductionmentioning

confidence: 99%

“…Their use increases the number of eutectic colonies in the microstructure, with carbides featuring more favorable morphologies. As was mentioned in previous works [ 2 , 3 ], in order to create an effective underlay the mismatch δ between lattice parameters of the underlay and the phase that one wants to inoculate has to be low. The effectiveness of inoculation decreases when the mismatch δ is higher than 6%.…”

Section: Introductionmentioning

confidence: 99%

“…Chung et al [ 6 ] proved that the addition of carbide forming elements V, B, and Nb may result in enhanced performance under pin-on-disc testing conditions. Interesting results can be obtained after adding rare earth elements such as Ce and La into the melt [ 3 , 4 , 5 , 10 , 11 , 12 ]. The lattice parameters of Cr 7 C 3 carbides are a = b = 6.99 Å, c = 4.036 Å; while the parameters of Ce 2 O 2 S are a = b = 6.942, c = 4.036 Å ( δ = 0.69) in a hexagonal system [ 3 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

“…Interesting results can be obtained after adding rare earth elements such as Ce and La into the melt [ 3 , 4 , 5 , 10 , 11 , 12 ]. The lattice parameters of Cr 7 C 3 carbides are a = b = 6.99 Å, c = 4.036 Å; while the parameters of Ce 2 O 2 S are a = b = 6.942, c = 4.036 Å ( δ = 0.69) in a hexagonal system [ 3 , 10 ]. The low mismatch δ between lattice parameters of Ce 2 O 2 S and Cr 7 C 3 makes the Ce 2 O 2 S compounds suitable crystallization underlays for Cr 7 C 3 eutectic chromium carbides.…”

Section: Introductionmentioning

confidence: 99%

“…The low mismatch δ between lattice parameters of Ce 2 O 2 S and Cr 7 C 3 makes the Ce 2 O 2 S compounds suitable crystallization underlays for Cr 7 C 3 eutectic chromium carbides. Studies in this area show that the addition of rare earth elements improves the morphology of the carbide phase and make carbides more rounded and refined [ 3 , 10 , 11 , 12 ]. The microstructure refinement after the addition of Ce and La, resulting in better wear resistance [ 3 , 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

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Bifilm Defects in Ti-Inoculated Chromium White Cast Iron

Dojka

Stawarz

2020

Materials

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In recent years, white chromium cast iron has gained a well-settled position among wear-resistant materials. In recent times, chromium cast iron samples containing titanium have attracted attention. In cast iron samples, titanium combines with carbon and forms TiC particles, which may be form a crystallization underlay for eutectic M7C3 carbides and austenite. Accordingly, the inoculation process occurring in the crystallizing alloy should result in the proper, regular distribution of fine eutectic chromium carbides in the austenitic matrix. The presented research was conducted on 20% Cr hypoeutectic white cast iron with the addition of 0.5, 1, and 2% of Ti. Ti inoculation and the presence of TiC allowed for superior wear properties to be obtained. However, the conducted study revealed a significant decrease in the impact strength of examined alloys, especially for the cast iron samples with a high amount of Ti, in which the TiC compounds agglomerated. Titanium compounds accumulate in clusters and their distribution is irregular. Most of the TiC compounds were transported by the crystallization front into the center of the castings, where micropores were formed, meaning they were no longer effective crystallization underlays. In the authors’ opinion, the agglomerate formation is strictly connected with the appearance of bifilm defects in the casting microstructure. The conducted research shows how an incorrect volume of an additive may have negative influences on the properties of the casting. This is a vital issue not only from a technological point of view, but also for economic reasons.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Bifilm Defects in Ti-Inoculated Chromium White Cast Iron

Dojka

Stawarz

2020

Materials

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Corrosion Resistance of Selected Cast Iron Grades Under Deposit Mining Conditions

Stawarz

Dojka

2021

Inter Metalcast

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The paper analyzes two types of alloyed cast iron used for pump impellers operated in mine working conditions. The research on corrosion resistance of two cast iron grades resistant to abrasive wear was presented. Tests were performed for chromium cast iron (HCCI) grade EN-GJN HV600 (XCr18) (acc. to EN 12513) and high-silicon cast iron HSCI Grade 1 (acc. to ASTM A 518/ A 518M - 99). Deposit mining is characterized by variable working conditions. Both types of cast iron are resistant to abrasive wear and are suitable for loaded elements (e.g. pump impellers). The paper presents a metallographic analysis of selected cast iron grades based on light microscopy. The chemical composition of the tested cast irons was determined with the Leco GDS 500 spectrometer; C and S content was determined with the CS125 Leco Carbon–Sulfur Determinator. The Si content for HSCI Grade 1 was determined by gravimetric method. Corrosion tests were performed under laboratory conditions. In-service tests of cast impellers were performed under real conditions (working mines applications). Corrosion resistance tests were measured with VoltaLab® Potentiostat (PGP 201). Performed tests resulted in the determination of the usefulness of materials used for dewatering pump impellers in mine working conditions. The results of laboratory tests were verified under the operating conditions of cast impellers. In the conditions of transporting a liquid-solid mixture at the moment of appearance of impurities (e.g. chlorine impurities) in the liquid, the impellers from cast iron HCCI revealed a tendency to pitting corrosion, which explains the exploitation results collected in the mining. After laboratory tests for sample from HCCI, the low value of breakdown potential Eb and repassivation Ecp was concluded which says about the absence of pitting corrosion resistance.

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Study of possibility of manufacture of the complex titanium-containing ferroalloy via single-stage carbothermal method

Vorobkalo¹,

Makhambetov²,

Baisanov³

et al. 2022

cisisr

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The object of research is the melting technology of a complex titanium-containing ferroalloy by single-stage slagfree carbothermal method using high-ash coals as a reducing agent. The ilmenite concentrate (Shokash deposit, Aktobe region, Kazakhstan), rich titanium slag, which was obtained by the scientists of the Chemical and Metallurgical Institute named after Zh. Abishev (Karaganda, Kazakhstan), as well as high-ash coal as a reducing agent were used as charge materials. Several physical-chemical characteristics of used charge materials were previously studied to carry out large-scale labour tests on the complex titanium-containing ferroalloy melting via single-stage slag-free carbothermal method. The chemical and phase composition of materials was established and two optimal compositions of the charge mixture for alloy melting were selected on their basis. The first composition contains: coal -67.35 %; rich titanium slag -26.12 %; quartzite -6.5 %. The second composition includes^ coal -66.95 %; rich titanium slag -23.1 %; ilmenite -3.3 %; quartzite -6.61 %. Tests for melting of a new complex titanium-containing ferroalloy were conducted in the ore-smelting furnace with 0.2 MVA transformer power. As a result of the tests, a batch of new complex titanium-containing ferroalloy was obtained, with the following average chemical composition: Ti -18-21 %; Si -35-45 %; Al -10-20 %; P is no more than 0.08 %, the rest is Fe. Also metallographic studies of the alloy sample were carried out in the work. The obtained alloy according corresponds in its titanium content to the brand FeTi25 (GOST 4761-91). The test results showed the principal possibility of obtaining a new complex titanium-containing ferroalloy from rich titanium slag and ilmenite concentrate using high-ash coal as a reducing agent.

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Influence of Ti and REE on Primary Crystallization and Wear Resistance of Chromium Cast Iron

Cited by 11 publications

References 18 publications

Bifilm Defects in Ti-Inoculated Chromium White Cast Iron

Bifilm Defects in Ti-Inoculated Chromium White Cast Iron

Corrosion Resistance of Selected Cast Iron Grades Under Deposit Mining Conditions

Study of possibility of manufacture of the complex titanium-containing ferroalloy via single-stage carbothermal method

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