• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.6
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• pp.180-192
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• 2008

The purpose of this research is to evaluate the structural performance of mortar-filled ductile cast iron sleeve splice developed for SD500 high-strength reinforcing bar under cyclic loading. The test variables adopted in this study are the development length of bar, compressive strength of mortar, bar size, sleeve types and others. In this research, it is showed that the mortar-filled sleeve splice for SD500 high-strength bar satisfied the structural performance required in ACI, AIJ code as well as domestic code. Also the results of experimental research presented in this paper provided basic engineering data for developing a reasonable design method of mortar-filled sleeve splice for SD500 high-strength reinforcing bar.

• Korean Journal of Materials Research
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• v.10 no.1
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• pp.41-48
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• 2000

In this study, microstructure and mechanical properties and electrical conductivities of in situ Cu-Fe-Xi(Xi=Ag, Cr or Co) alloy wires obtained by cold drawing combined with intermediate heat treatments have investigated. During cold working the primary and secondary dendrite arms are aligned along the drawing direction and elongated into filaments after deformation processing. The addition of Ag was found to be more effective in reducing the microstructural scale at the given draw ratio than that of Co or Cr throughout the drawing processing. The ultimate tensile strength and the conductivity of the Cu-Fe based composites containing Ag were higher than those of Cu-Fe composites containing Co or Cr. The good mechanical and electrical properties of Cu-Fe-Ag wires may be associated with the more uniform distribution of the finer filaments in the wires containing silver. The strength of Cu-Fe-Xi composites is dependent on the spacing of the Fe filaments in accord with a Hall-Petch relationship. The fracture surfaces of all the specimens showed ductile-type fracture and iron filaments occasionally observed on the fracture surfaces.

• Journal of Korea Foundry Society
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• v.41 no.2
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• pp.144-152
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• 2021

Based on the analysis of the current state of the world's foundry industry, we looked at the international competitiveness of Korea's foundry industry for the past 20 years. Korea's total foundry production is 2.52 million tons, and the production per company (so-called productivity) is 2,831 tons, which is the eighth largest in the world and down one position for the case of total foundry production, while productivity remains its position compared to three years ago. Korea is the only one of the top 10 foundry to see a decline in production. Similar to the global situation, Korean products consist of 38% of grey csat iron, 31% of ductile cast iron, 15% of aluminum, and 9% of cast steel. In order to obtain statistics on Korea's foundry industry, the survey conducted a service project for approximately nine months from April 2020. Various statistical surveys and sample in-depth surveys by the Korean standard industry class were evaluated for various contents of the domestic casting industry. We also looked at the number of companies, the distribution by region, the number of workers and the percentage of foreigners, and the distribution of each job, as well as the R&D investment status according to the size of the enterprise. Together, sales, exports, sales and various profit ratios were analyzed to measure the earning power of foundry industry. In addition, the classification by grouping the foundry industry according to the process utilized by focusing on each company, and to determine the sales, exports, and yield status for each process was also investigated on the basis. Based on these data, the domestic foundry industry has presented a variety of offers for the following issues for sustainable growth; global ranking, marginal corporate restructuring, training of domestic technical people, differentiated support policies by company size and process.