• Corrosion Science and Technology
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• v.21 no.5
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• pp.418-421
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• 2022

Stir-accelerated corrosion test of a high chromium cast iron was attempted in 0.1 mol dm^-3 H₂SO₄ + 0.05 mol dm^-3 HCl + 10 wt% SiC solution for 48 h at room temperature or at 45 ℃. The high chromium cast iron was composed of 2.8 wt% C and 27 wt% Cr and balanced with Fe. The high chromium cast iron was positioned into a 500 mL beaker with stirring of the solution at 1050 rpm using a magnetic hot plate. The corrosion rate was increased by agitating the solution. In addition, the corroded depth of the high chromium cast iron surface was increased by agitating the solution. The surface morphology of the high chromium cast iron after the stir-accelerated corrosion test revealed that a dendritic austenite phase partially remained in the corroded region after agitating the solution, indicating that solution movement during agitating could accelerate the corrosion rate of the high chromium cast iron.

• Bulletin of the Korean Space Science Society
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• 2005.10a
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• pp.65-65
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• 2005

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.96-96
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• 2004

• Journal of Korea Foundry Society
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• v.24 no.4
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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.

• Journal of Korea Foundry Society
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• v.24 no.4
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• pp.217-224
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• 2004

The effect of casting variable on the fluidity of high silicon, especially hypereutectic, heat-resistant ductile cast iron melt was investigated. When pouring temperature and silicon content were constant, that was increased with carbon content. When the pouring temperature and carbon content were constant, that also increased with the silicon content. Even though these results were thought to be caused by the high heat of fusion evolved during the crystallization of proeutectic graphite nodules, further research seemed to be needed. The fluidity for taller sprue was higher than that for smaller one.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.04a
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• pp.176-183
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• 1995

The design process of pre-cast concrete member needs various design parameters and the engineer's experiences. The introduction of knowledge-based system in the design of pre-cast concrete member enables us to design complicated members using the designer's heuristics. The objectives of this research are to study useful methodology for representing knowledge and data in the development of knowledge-based system and to show the application of methodology by developing a prototype sysytem for design of pre-cast concrete member. This paper nrst describes methodology for building knowledge-based system. It then presents knowledge-based system for pre-cast concerete member design.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.209-216
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• 2004

Numerical analysis is carried out to identify the appropriateness of the design codes that is available for the tensile design of fastening system at Nuclear Power Plant (NPP) in this study. This study is intended for the cast-in-place anchor that is widely used for the fastening of equipment in Korean NPPs. The microplane model and the elastic-perfectly plastic model are employed for the quasi-brittle material like concrete and for the ductile material like anchor bolt as constitutive model for numerical analysis and smeared crack model is employed for the crack and damage phenomena. The developed numerical model is verified on a basis of the various test data of cast-in-place anchor. The appropriateness of both ACI 349 Code and CCD approach of CEB-FIP Code is evaluated for the tensile design of cast-in-place anchor and it is proved that both design codes give a conservative results compared with real tensile capacity of cast-in-place anchor.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1994.04a
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• pp.17-24
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• 1994

In the analysis pre-cast large panel structures, we can use the new discrete analyzing method to be consisted of rigid bodies. Because the pre-cast panels we still more rigid than the connection, the rigid element method is more efficient numerical method than F. E. M. The characteristics of R. E. M. is that strains in element are not occurred by external loadings and the deformation of the structures by external loadings is transmitted through springs around elements. In this study, we focus on the comparison of the results from the R. E. M. and the F. E. M. in order to establish the validity of the R. E. M. to analysis of pre-cast panel structures.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.291-296
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• 2004

Cast austenitic stainless steel piping pump, valve casings, and elbows are susceptible to reductions in toughness and ductility because of long term exposure at the operating temperatures in LWR(light water reactor). In this paper, we have measured the material properties of long term aged CF-8A cast stainless steel, accelerated aging at $400^{\circ}C$. These studies have been carried out using Indentation tests(automated ball indentation and nano-indentation) and EDS(energy dispersive spectroscopy). The fracture toughness of CF-8A cast stainless steel was also determined by using standard fracture toughness and Automated Ball Indentation.

• Journal of the Korean Society for Heat Treatment
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• v.12 no.1
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• pp.40-46
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• 1999

Rotary bending fatigue tests were carried out to investigate the improvement of fatigue limit in annealed and austempered spheroidal graphite cast iron. Main results obtained are as follows. (1) The tensile strength(hardness) of Series C is higher than that of Series B, and fatigue limits are 245MPa in Series C, 230MPa in Series B and 195MPa in Series A, respectively. (2) The fatigue limits of Series B and Series A are mainly governed by the resistance to fatigue crack initiation. Whereas, the fatigue limit of Series C is governed by the resistance to fatigue crack initiation and growth. The defect size and the resistance to crack initiation and growth should be considered to clarify the fatigue properties in spheroidal graphite cast iron. (3) Improvement of fatigue limit by half-austempering is more reasonable than that of full-austempering treatment in multi defective materials as spheroidal graphite cast iron.