Effects of Cu and Other Tramp Elements on Steel Properties. Necessity of Scrap Reclamation Technologies and Present Conditions of Technical Development.

Noro, Katsuhiko; Takeuchi, Mitsugu; Mizukami, Yoshimasa

doi:10.2355/isijinternational.37.198

Cited by 57 publications

(34 citation statements)

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“…3) For this reason there are limits on the Cu and Sn contents in each kind of steel. 1) But the concentration of Cu in a certain kind of steel scrap is now higher than the maximum tolerable limit. 1) From the viewpoint of recycling of steel, the surface hot shortness is the most serious problem.…”

Section: Introductionmentioning

confidence: 99%

“…As for the methods y and z, over the past ten years in Japan, tremendous efforts have been made in order to remove Cu and Sn from steel scrap and steels. 1) In those activities, several methods have been proposed. But it has never been clarified whether they are applicable in the practical processes of steel recycling.…”

Section: Introductionmentioning

confidence: 99%

“…As a natural result, the amount of steel scrap, especially obsolete steel scrap, is expected to increase at a considerable rate. 1) Therefore the usage of steel scrap has become important in steel manufacturing in Japan from the viewpoints of resource saving and preventing environmental problems.…”

Section: Introductionmentioning

confidence: 99%

“…That is to say, concentrations of Cu and Sn, especially Cu, in steel scrap are increasing. 1) Copper is mainly contained in the scrap of cars and home electronic appliances. Tin is mainly contained in the scrap of tin-coated cans.…”

Section: Introductionmentioning

confidence: 99%

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Suppression of Surface Hot Shortness due to Cu in Recycled Steels

et al. 2002

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The most serious problem in the recycling of steel is the occurrence of surface hot shortness during hot deformation due to the mixing of Cu from scrap into steels. Tin accelerates the effect of Cu. The surface hot shortness is caused by liquid embrittlement, that is, formation of the liquid Cu-enriched phase through preferential oxidation of Fe atoms at the steel/scale interface during heating for hot deformation and penetration of this Cu-enriched phase into the grain boundaries. Decrease in the amount of the liquid Cu-enriched phase penetrating into grain boundaries can suppress the surface hot shortness. The amount of the liquid Cu-enriched phase penetrating into the grain boundaries can be reduced by the suppression of oxidation, occlusion of the Cu-enriched phase into the scale, back-diffusion of Cu into the steel matrix and suppression of penetration of the liquid Cu-enriched phase. Therefore, the effects of various elements and conditions of heating and deformation on the surface hot shortness, oxidation, amount of the Cu-enriched phase at the interface and the penetration were examined by tensile tests at high temperatures, thermogravimetry and optical microscopy. The conclusion can be summarized as follows. Silicon, Mn, S (+Mn) and B reduce the susceptibility to the surface hot shortness through decreasing the amount of Cu-enriched phase at the steel/scale interface. The effect of Si is significant. Carbon reduces the oxidation rate in LNG combustion gas. Phosphorus, Si, B and C reduce the susceptibility to the surface hot shortness through restraining the penetration of the Cu-enriched phase into grain boundaries. Heating at higher temperatures reduces the susceptibility mainly through a reduction in the amount of the Cu-enriched phase at the steel/scale interface, although the loss of steels by oxidation increases. A large grain size accelerates the surface hot shortness. A small amount of H 2 O in air significantly accelerates the surface hot shortness. Effects of H 2 O in heating atmosphere depend on the steel composition and more detailed research on this is desired. Very slow deformation does not cause liquid embrittlement through dynamical re-crystallization, while at a fast deformation rate the embrittlement is suppressed by an increase in the critical stress for the liquid embrittlement. Multiple methods using physical metallurgy suggested by the present research for suppressing the surface hot shortness should be applied together with other methods through separation, smelting and design of fabrication in order to promote the recycling of steels.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Suppression of Surface Hot Shortness due to Cu in Recycled Steels

et al. 2002

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“…Steel recycling is commonly used because it is environmentally friendly in the sense that the reduction of iron oxide is not required to obtain the molten metal and therefore CO 2 emissions and energy requirements are reduced. 4) However, this steelmaking process presents some drawbacks related to the higher content of residual elements, i.e. Cu, Sn, Ni, Sb or As, and impurities.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Hot Ductility of a C–Mn Steel Produced from Scrap Recycling

Calvo¹,

Cabrera²,

Ahmad

et al. 2007

ISIJ Int.

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The use of scrap for the production of steel has been related to a high incidence of transverse cracking during continuous casting. This phenomenon is linked to the high contents on residual elements and impurities present in recycled steels. In order to understand the embrittlement mechanisms that can take place at high temperatures, the hot ductility of a C-Mn steel with residual contents of Cu and Sn was analyzed. The steel was evaluated in two as-received conditions, i.e. as-cast and as-rolled, and samples were subjected to different reheating and in-situ melting cycles prior to tensile tests. Testing temperatures ranged from 650 to 1 100°C and strain rate was 5 · 10 Ϫ3 s Ϫ1. Results show that the width and depth of ductility troughs depend on both the reheating cycle and the as-received condition of the material. According to the fractographical analysis, a reheating of the samples at 1 100°C leads to a combined intergranular and interdendritic fracture while samples reheated at 1 330°C exhibit mainly intergranular features at temperatures in the ductility trough. The interdendritic brittleness for samples reheated at the low temperature is related to the microsegretation taking place during solidification as it can be demonstrated with samples in-situ melted. On the other hand, intergranular brittleness is related to the segregation of impurities and residuals to grain boundaries. The recovery of the ductility in the high temperature range is associated to the appearance of D-REX. The differences observed between the as-cast and as-rolled as-received condition of the steel are associated to differences in the austenite grain size and its effect on dynamic recrystallization.

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Efficiency of Resources for Production of Density Reduced Steels by Direct Strip Casting

Klöpfer

Bach

Evertz

et al. 2012

Chemie Ingenieur Technik

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Das Bandgießen bietet beachtliche Chancen zur energieeffizienten und ressourcenschonenden Erzeugung von Warmband bei gleichzeitig erheblichen Anforderungen an die Anlagen-und Prozessentwicklung des endabmessungsnahen Gießverfahrens. Das Verfahren ermöglicht insbesondere die Herstellung von hochmanganhaltigen Stählen, wie dem HSD ® -Stahl oder weiter dichtereduzierten Stahlsorten. Im ersten Schritt wurde der Al-Gehalt bis zu 8 Gew.-% variiert, die mechanischtechnologischen und physikalischen Eigenschaften sind hier dargestellt.Direct strip casting offers significant prospects for resource-saving and energy-efficient production of hot strip. It is associated with substantial demands on the system and process development of a near net shape casting process. The technique allows in particular the production of high-manganese steels, such as the HSD ® steels or additionally density reduced steels. In the first step Al content was varied up to 8 wt %. The according mechanical and physical properties are shown here.

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Effects of Cu and Other Tramp Elements on Steel Properties. Necessity of Scrap Reclamation Technologies and Present Conditions of Technical Development.

Cited by 57 publications

References 0 publications

Suppression of Surface Hot Shortness due to Cu in Recycled Steels

Suppression of Surface Hot Shortness due to Cu in Recycled Steels

Evaluation of the Hot Ductility of a C–Mn Steel Produced from Scrap Recycling

Efficiency of Resources for Production of Density Reduced Steels by Direct Strip Casting

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Effects of Cu and Other Tramp Elements on Steel Properties. Necessity of Scrap Reclamation Technologies and Present Conditions of Technical Development.

Cited by 57 publications

References 0 publications

Suppression of Surface Hot Shortness due to Cu in Recycled Steels

Suppression of Surface Hot Shortness due to Cu in Recycled Steels

Evaluation of the Hot Ductility of a C&ndash;Mn Steel Produced from Scrap Recycling

Efficiency of Resources for Production of Density Reduced Steels by Direct Strip Casting

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Product

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Evaluation of the Hot Ductility of a C–Mn Steel Produced from Scrap Recycling