• 한국주조공학회지
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• 제24권4호
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• pp.202-208
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• 2004

Effects of Co addition on sliding wear properties of multi-component white cast iron were investigated. The microstructures of multi-component white cast iron containing from 0%Co to 10%Co exhibited little difference. However, the hardness increased with an increase of the Co content. Increasing the Co content, wear properties were improved and the iron oxide on worn surface was increased in the low sliding speed range of the steady-state wear region. Hence, Co addition was effective to improve the wear properties of multi-component white cast iron by accelerating the corrosive wear as well as the enhancement effect of hardness.

• 한국재료학회지
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• 제7권4호
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• pp.310-316
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• 1997

The effects of carbide and matrix structures on the abrasion wear resistance of multi-component white cast irons with 3.0 mass%C have been studied in this paper. Four different heats were poured in order to obtain the specimens with different combinations of the carbide structures: a basic iron(3.0 mass%C-5.0 mass%Cr-5.0 mass%V-5.0 mass% Mo-12.5mass%W)for M$_{6}$C and M$_{7}$C$_{3}$ carbides, and a Cr free iron(3.0 mass%C-5.0 mass%V-2.5mass%Mo-12.5 mass%W) for MC and M6C carbides. A conventional high Cr free free iron(3.0 mass%C-5.0 mass%V-2.5 mass%Mo-12.5 mass%W) for MC and M6C carbides. A conventional high Cr white cast iron was also poured to compare its wear resistance with those of the multi-component white cast irons. In the as-cast condition, the range of abrasive wear rate(Rw=mg/min) was from 4.15 to 5.98 . The lowest Rw, which means the highest wear resistance, was obtained in the basic iron with nodular MC, lamellar M$_{2}$C and cellular M$_{7}$C$_{3}$ carbides. On the other hand, the Rw of the high Cr white cast iron ranked between the basic iron and the Mo and W free iron. In each alloy, the Rw of air hardened or tempered specimen was lower than that of the as-cast one because of the change of matrix structures by the heat treatments. The Rw of the hear treated speci-mens increased in the order Mo and W free iron, basic iron, Cr free iron, high Cr iron, and V free iron.n.n.n.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2009년 추계학술발표대회
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• pp.38-38
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• 2009

36 percent nickel-iron alloy possesses a useful combination of low thermal expansion, moderately high strength and good toughness at temperatures down to that of liquid helium, $-269^{\circ}C$. These propeties coupled with good weldability and desirable physical properties make this alloy attractive for many cryogenic applications such as the cargo containment system in Liquefied Natural Gas carriers and pipes for low temperature. Generally, welding method of the 36% nickel-iron is applied with the manual and autogeneous GTAW. Lately white spots have been observed on the some autogeneous GTA welds of them. But the white spot formation have not been studied yet. This paper covers the analysis results of the white spots formation as changing welding variables.

• 한국재료학회지
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• 제24권7호
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• pp.363-369
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• 2014

This is the study on diffusion of ceramic body oxide compounds to glaze. For ceramic bodies, no ferrous oxides contain white ware, celadon, and 3 wt% iron oxides contained white ware was used in this experiment. These ceramic bodies were glazed by transparency glaze, iron oxides contained glaze, and glaze made by pine tree ash that treated in 1240 degree, under reduction condition for an hour. An electron probe microanalyzer(EPMA) was used to study diffusion of oxides and to calculate distance of ceramics bodies. As a result, only iron oxide and magnesium oxide from the body diffused to glaze, and also made a band which shown very thin layer of iron oxide and magnesium oxide between the body and glaze. The densest band of iron oxide formed 100 to $150{\mu}m$ in the glaze, and the densest band of magnesium oxide was found 50 to $100{\mu}m$ in the glaze. Therefore, it could be concluded that iron oxide in the body is diffused to the glaze and it affects the color of glaze, even though iron oxide exists in the glaze. Furthermore, the thickness of the glaze has an effect on the color of celadon.

• 한국주조공학회지
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• 제35권6호
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• pp.178-184
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• 2015

Due to excellent abrasion resistance the high-chrome white irons are widely used in mining and mineral industries. Minor variation of carbon content in 28% chrome white iron resulted in difference in primarily solidified microstructure. Sub-eutectic (hypoeutectic) composition led to formation of primarily solidified dendrites. Formation of primarily solidified dendrites which were supersaturated with carbon and chrome also caused precipitation of fine secondary carbides that are different from relatively large plate type $M_7C_3$ carbides in the eutectic structure. Small portion of primarily solidified dendrite expected to contribute significantly to the improvement of abrasion resistance of the white iron because the dendrites provided mechanical support to carbides. The relative fraction of primary dendrite increased with reduction of carbon content from the eutectic composition. The increased fraction of primary dendrite increased hardness value of the white irons.

• Corrosion Science and Technology
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• 제23권4호
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• pp.310-314
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• 2024

The corrosion behavior of high chromium white cast iron was studied in 0.5 mol dm^-3 H₂SO₄ + 0.01 mol dm^-3 HCl solution over time through electrochemical and immersion experiments. Potentiodynamic and potentiostatic polarizations revealed active-passivation transition behavior, with critical current densities observed at -0.27 V_SSE and 0.00 V_SSE, repectively. The former potential showed preferential dissolution of primary γ phases, while the latter one showed preferential dissolution of eutectic γ phases. Immersion tests showed an exponential increase in corrosion rate, with significant acceleration observed around 1000 seconds due to the onset of eutectic γ phase dissolution. Over a 24-hour immersion period, both γ phases exhibited extensive corrosion, leaving carbides largely intact. These findings elucidate distinct corrosion behaviors of high chromium white cast iron in acidic environments, providing critical insights into material performance evaluation. Understanding these mechanisms is essential for predicting the longevity and durability of materials in corrosive conditions, thereby informing better material design and application strategies.

• 한국재료학회지
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• 제11권6호
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• pp.472-476
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• 2001

광학 및 주사전자현미경을 사용하여 X%C-5%Cr-5%V-5%Mo-5%W-5%Co 조성을 가진 다합금계백주철에서 정출되는 탄화물의 종류 및 형태를 3차원적으로 관찰하였는 바 MC, M$_2$C 및 M$_{7}$C$_{3}$의 3종류의 탄화물이 정출되었다. MC탄화물은 꽃잎, 구상 그리고 산호초형태의 3종류, M$_2$C탄화물은 층상 및 판상의 2종류, M$_{7}$C$_{3}$7탄화물은 고크롬백주철에서 관찰되는 막대형태의 한 종류만 관찰되었다. 첨가한 합금원소중 Co는 기지조직에만 고용되었기 때문에 탄화물의 현상에는 영향을 미치지 않았다.않았다.

• Journal of Nutrition and Health
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• 제54권5호
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• pp.435-447
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• 2021

Purpose: Body adiposity is negatively correlated with hepatic iron status, and Korean pine nut oil (PNO) has been reported to reduce adiposity. Therefore, we aimed to study the effects of PNO on adiposity, hepatic mineral status, and the expression of genes and proteins involved in iron absorption. Methods: Five-week-old male C57BL/6 mice were fed a control diet containing 10% kcal from PNO (PC) or soybean oil (SBO; SC), or a high-fat diet (HFD) containing 35% kcal from lard and 10% kcal from PNO (PHFD) or SBO (SHFD). Hepatic iron, copper, and zinc content; and expression of genes and proteins related to iron absorption were measured. Results: HFD-fed mice had a higher white fat mass (2-fold; p < 0.001), lower hepatic iron content (25% lower; p < 0.001), and lower hepatic Hamp (p = 0.028) and duodenal Dcytb mRNA levels (p = 0.037) compared to the control diet-fed mice. Hepatic iron status was negatively correlated with body weight (r = -0.607, p < 0.001) and white fat mass (r = -0.745, p < 0.001). Although the PHFD group gained less body weight (18% less; p < 0.05) and white fat mass (18% less; p < 0.05) than the SHFD group, the hepatic iron status impaired by the HFD feeding did not improve. The expression of hepatic and duodenal ferroportin protein was not affected by the fat amount or the oil type. PNO-fed mice had significantly lower Slc11a2 (p = 0.022) and Slc40a1 expression (p = 0.027) compared to SBO-fed mice. However, the PC group had a higher Heph expression than the SC group (p < 0.05). The hepatic copper and zinc content did not differ between the four diet groups, but hepatic copper content adjusted by body weight was significantly lower in the HFD-fed mice compared to the control diet-fed mice. Conclusion: HFD-induced obesity decreased hepatic iron storage by affecting the regulation of genes related to iron absorption; however, the 18% less white fat mass in the PHFD group was not enough to improve the iron status compared to the SHFD group. The hepatic copper and zinc status was not altered by the fat amount or the oil type.

• Journal of Welding and Joining
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• 제20권4호
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• pp.551-556
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• 2002

Solid particle erosion wear characteristics of high Cr white iron hardfacing were investigated using the erosion wear test method according with the ASTM G76-95. Wear experiments, where the blast angle, blast distance and blast pressure were selected as test variables, were planned and analyzed by response surface method (RSM to evaluate the wear loss statistically and quantitatively. The measured wear losses well coincided with the calculated ones by the experimental equation. The wear loss of high Cr cast iron hardfacing was increased with blasting pressure, but affected in a complicated way by the blasting angle and distance. Erosion wear of high Cr cast iron hardfacing could be well predicted by RSM analysis of wear variables.

• Asian-Australasian Journal of Animal Sciences
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• 제29권5호
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• pp.695-701
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• 2016

This study was conducted to observe antioxidant enzyme activity, iron content and lipid oxidation of Korean native chickens and other poultry. The breast and thigh meat of three Korean native chicken breeds including Woorimatdak, Hyunin black and Yeonsan ogye, and three commercial poultry breeds including the broiler, White Leghorn and Pekin duck (Anasplatyrhyncos domesticus) were studied. The analyses of the antioxidant enzymes activity, iron content and lipid oxidation were performed in raw and cooked samples. The activity of catalase (CAT) in the thigh meat was higher than that of the breast meat of three Korean native chickens and the broiler, respectively. The activity of glutathione peroxidase (GPx) in the uncooked thigh meat of three Korean native chickens was higher than that of the breasts. The breast meat of Woorimatdak and Pekin duck had higher superoxide dismutase (SOD) activity than the others, while only the thigh meat of Pekin duck had the highest activity. Cooking inactivated CAT and decreased the activity of GPx and SOD. The thigh meat of Woorimatdak, White Leghorn, Yeonsan ogye and Hyunin black contained more total iron than the breast meat of those breeds. The heme-iron lost during cooking ranged from 3.2% to 14.8%. It is noted that the thigh meat had higher thiobarbituric acid reactive substances values than the breast in all chicken breeds. Though Woorimatdak showed higher antioxidant enzyme activity and lower released-iron percentage among Korean native chickens, no differences were found on lipid oxidation. We confirm that the dark meat of poultry exhibited higher antioxidant enzyme activity and contained more iron than the white meat.