• Journal of Korea Foundry Society
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• v.14 no.5
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• pp.419-428
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• 1994

The microvickers hardness and microstructure of Fe/Al composite fabricated by squeeze casting method were investigated. Pure Al and A356 Alloy were chosen for the matrix composition and Fe preform was fabricated with sintered Fe powder at $1000^{\circ}C$ for 30min. under hydrogen atmosphere. Experimental variables were included preheating temperature, melt temperature and applied pressure. Analysing the experimental result concerning microstructure of fabricated composites, Fe/A356 composite showed improved microstructure at $600^{\circ}C$ melt temperature and $350^{\circ}C$ preform preheating temperature in Fe distribution and Infiltrated distance. The results of EDX and XRD showed that the interfacial zones of Fe/Al composite were composed of non-equilibrium intermetallic layers[$(Al_5Fe_2)_x$, $Al_{13}Fe_4m\;Fe_3Al$, FeAl]. The microvickers hardness of Fe/Al composite showed higher value than Fe/A356 composite in interface.

• Journal of Korea Foundry Society
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• v.39 no.1
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• pp.1-6
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• 2019

During the casting process, it is possible to minimize shrinkage and blowholes by modifying the casting design. However, it is impossible to eliminate these factors completely. Therefore, mechanical design engineers apply a sufficient safety factor owing to the possibility of insufficient performances of the cast products. In this paper, prediction method of the fatigue life of cast products containing shrinkage is conducted by using CT (computed tomography) and the SSM (shape simplification method), and additional fatigue analyses are carried out. The analysis results are then compared to results from actual experiments on samples with shrinkage defects. It is found to be that the considering actual shrinkage in cast products by means of stress and fatigue analyses is more accurate and effective. It is also considered that the proposed hot spot method provides us a good tool to predict the fatigue lifes of cast product.

• Journal of Korea Foundry Society
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• v.32 no.5
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• pp.231-240
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• 2012

In present study, the effect of heat treatment on the microstructure and mechanical properties of the gravity cast superchargers housing using A356 alloy were investigated. In order to identify the characteristics of superchagers housing casting with heat treatment, Vickers hardness test, electrical conductivity test, opical and scanning electron microscopy were performed. And also, to investigate their mechanical properties, the T6 treated superchagers housing casting in optimum heat treatment condition were carried out tensile test using UTM (Universal Testing Machine).

• Korean Journal of Metals and Materials
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• v.49 no.1
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• pp.73-78
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• 2011

Weldability, especially HAZ cold cracking, weld metal solidification cracking, and HAZ liquation cracking susceptibilities, of ASTM A356 CA6NM martensitic stainless steel casting was investigated and compared with that of 9-12% Cr ferritic steel castings. Irrespective of the Cr and Ni content in the castings, the HAZ maximum hardness increased with an increase of carbon content. CA6NM steel, which has the lowest carbon content, had the lowest HAZ hardness and showed no cold cracking in y-slit cracking tests. CA6NM steel, meanwhile, showed the largest weld metal solidification cracking susceptibility in varestraint tests because of its higher amount of impurity elements, phosphorus, and sulfur. All castings investigated had good high temperature ductility in hot ductility tests and showed little difference in liquation cracking susceptibility.

• Transactions of Materials Processing
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• v.18 no.4
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• pp.296-303
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• 2009

The effect of porosity on the high-cycle fatigue properties of Al-Si-Mg casting aluminum alloys was investigated in this study. Microstructure examination, tensile and high-cycle fatigue test were conducted on both Al-Si-Mg casted (F) and heat-treated (T6) conditions. Porosity characteristics on the fracture surfaces of fatigue-tested samples were examined using SEM and image analysis. The microstructure observation results showed that eutectic Si particles were homogeneously dispersed in the matrix of the Al-Si-Mg casting alloys, but there were porosities formed as cast defects. The high-cycle fatigue results indicated that the fatigue strength of the 356-T6 alloy was higher than that of the 356-F alloys because of the significant reduction in volume fraction of pores by heat treatment. The SEM fractography results showed that porosity affected detrimental effect on the fatigue life: 80% of all tested samples fractured as a result of porosity which acted as the main crack initiation site. It was found that fatigue life decreased as the size of the surface pore increased. A comparison was made between surface pore and inner pore for its effect on the fatigue behavior. The results showed that the fatigue strength with the inner pores was higher than that of the surface pore.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.350-352
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• 2009

The effect of porosity on the high-cycle fatigue properties of Al-Si-Mg casting aluminum alloys was investigated in this study. Microstructure examination, tensile and high-cycle fatigue test were conducted on both Al-Si-Mg casted (F) and heat-treated (T6) conditions. Porosity characteristics on the fracture surfaces of fatigue-tested samples were examined using SEM and image analysis. The microstructure observation results showed that eutectic Si particles were homogeneously dispersed in the matrix of the Al-Si-Mg casting alloys, but there were porosities formed as cast defects. The high-cycle fatigue results indicated that the fatigue strength of the 356-T6 alloy was higher than that of the 356-F alloys because of the significant reduction in volume fraction of pores by heat treatment. The SEM fractography results showed that porosity affected detrimental effect on the fatigue life: 80% of all tested samples fractured as a result of porosity which acted as the main crack initiation site. It was found that fatigue life decreased as the size of the surface pore increased. A comparison was made between surface pore and inner pore fur its effect on the fatigue behavior. The results showed that the fatigue strength with the inner pores was higher than that of the surface pore.

• Investigative and Clinical Urology
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• v.59 no.6
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• pp.355-356
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• 2018

• The Korean Journal of Pain
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• v.18 no.2
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• pp.161-164
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• 2005

Background: Chemical lumbar sympathetic ganglion block could potentially be used to treat plantar hyperhidrosis; therefore, we analyzed the outcome of lumbar sympathetic ganglion block using alcohol for the treatment of plantar hyperhidrosis. Methods: Between March 1992 and June 2003, 356 patients with plantar hyperhidrosis underwent lumbar sympathetic ganglion block using alcohol. All 356 patients were followed up for 2 years and the results evaluated. There were 185 and 171 male and female patients, respectively, with a mean age of 25.1 years, ranging from 15.3 to 56.5 years old. Lumbar sympathetic ganglion block using alcohol was performed with fluoroscopic guidance under local anesthesia. Results: The recurrence rate after 2 years was 34%. Compensatory hyperhidrosis, ejaculation failure, lower back pain and genitofemoral neuritis developed as complications in 132, 4, 12 and 2 patients, respectively. Of the 356 patients, 65% were satisfied. Conclusions: Lumbar sympathetic ganglion block using alcohol is an effective and safe method for the treatment of plantar hyperhidrosis, but more information about the complications and relatively high recurrence rates should be provided to the patient.

• Bulletin of the Korean Chemical Society
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• v.23 no.2
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• pp.355-356
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• 2002

• Proceedings of the Korea Society of Costume Conference
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• 2004.08a
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• pp.356-357
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• 2004