Effects of Cu and Other Tramp Elements on Steel Properties. Effects of 0.4% Si and 0.02% P Additions on Surface Hot Shortness in 0.1%C-0.5%Mn Steels Containing 0.5% Cu.

Seo, Seok-Jong; Asakura, Kentaro; Shibata, Koji

doi:10.2355/isijinternational.37.240

Cited by 43 publications

(26 citation statements)

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“…On the other hand, Seo et al 5) found that the susceptibility to the surface hot shortness depended on the strain rate and showed the maximum at around 1 × 10 −1 s −1 . Figure 17 shows the effect of strain rate on stress-strain curves of specimens implanted with a Cu-20%Sn rod into 0.1%C-0.5%Mn-0.5%Cu steel.…”

Section: Effects Of Atmosphere Of Heating Furnace and Deformation Ratementioning

confidence: 99%

“…4, E p and E p at 1473 K are found to be maller than those at 1373 K. As for E e the effect of heating temperature is opposite and the reason for this has been mentioned before (3.2). It has been generally observed that the surface hot shortness tends to occur most severely around 1373 K. 2,5,12) The reasons for this result are conceived to be as follows. At higher temperatures, internal oxidation and grain boundary oxidation tend to occur and occlusion of the Cu-enriched phase into scale are accelerated.…”

Section: Effects Of Heating Temperaturementioning

confidence: 99%

“…Considering the above background, the present authors have stressed the necessity for the suppression of the surface hot shortness by physical metallurgy, namely, the method {. [4][5][6][7][8][9] The method { aims to suppress the surface hot shortness through controlling of microstructures near the steel/scale interface in order to reduce the amount of the liquid Cu-enriched phase penetrating into grain boundaries.…”

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: Effects Of Atmosphere Of Heating Furnace and Deformation Ratementioning

confidence: 99%

Section: Effects Of Heating Temperaturementioning

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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“…5) The silicon addition also decreases the amount of precipitated copper by the occlusion of copper in the oxide scale and reduces the susceptibility of hot shortness at 1 373 K, where the liquid Fe-Si oxide does not formed. 6) It is reported that the addition of phosphorus, carbon, and boron are favourable elements for hot shortness. These elements are thought to change the distribution of liquid copper in the scale, steel grain size, and the toughness of steel grain boundary for the crack propagation.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4] The addition of silicon also has been beneficial to this problem. 5,6) The addition of silicon reduces the susceptibility of hot shortness at more than 1 473 K, since the liquid precipitation of copper is trapped in the liquid oxide formed by silicon. 5) The silicon addition also decreases the amount of precipitated copper by the occlusion of copper in the oxide scale and reduces the susceptibility of hot shortness at 1 373 K, where the liquid Fe-Si oxide does not formed.…”

Section: Introductionmentioning

confidence: 99%