• Corrosion Science and Technology
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• v.2 no.5
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• pp.219-224
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• 2003

Crevice corrosion of stainless steels in natural seawater was investigated for several post weld treatments; as-annealed, as-welded, pickled, and ground. The results confirmed the effect of the biofilm on the cathodic reaction leading to an ennoblement of the rest potential. The degree of ennoblement of corrosion potential depends on the surface finish. As-annealed and pickled samples show stable corrosion potential approaching to 200 ~ 300 mV (SCE) while as-welded and ground samples show the fluctuating corrosion potential. This points to a situation where there are conflicting effects determining the trend in free corrosion potential. Crevice corrosion initiation will tend to pull the free corrosion potential in the active direction, whereas the presence of biofilm will tend to ennoble corrosion potential. There was no visible attack on UNS S31803, S32550, and 2205W. Therefore, those stainless steel grades appeared to be resistant to crevice corrosion in natural seawater on condition of weld metal.

• 보존과학연구
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• s.21
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• pp.101-118
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• 2000

Stone cultural properties(pagoda, Buddhist statue etc.) is moved in original place for many reasons and restored after taking to pieces for structural safety. With the movement and restoration after taking to pieces, the cast iron is used for the sake of a fixation and horizontality. The stone cultural properties are spoiled the beauty and accelerated the weathering because of the corrosion product of cast iron. So we need to substitute for the improved property in all aspects. We are executed the corrosion test and inquired the property of material on the usable material for the shim of stone cultural properties. That is the Cast iron, Stainless steel, Titanium and Fiber Reinforced Plastics. In the result of the physical property and strength, the Stainless steel and Titanium was superior to the Cast iron. And the Stainless steel and Titanium was slower than the Cast iron in the corrosion velocity for the acid, salt and rain. If the shim is substitute the Stainless steel or Titanium for the Cast iron, the stone cultural properties are able to reduce the pollution of stone cultural properties by corrosion product and should not happen in the matter of stone pagoda.

• Journal of Powder Materials
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• v.9 no.4
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• pp.203-210
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• 2002

A new PIM in-process joining technique has been developed for more complicated and functional PIM components by application of the exuded wax from the green compacts during solvent debinding step. At first, various stainless steels and iron compacts with rectangular shape were combined, and the joining behaviors and properties were investigated by shear and tensile test, and microscopic observation. Subsequently, perfect joined three pieces of thin and hollow compacts were obtained for the combination of same and different stainless steels, and it was difficult to join the iron and stainless steel compacts in hydrogen atmosphere because of the different starting temperature of shrinkage. However, pretty good joined iron and stainless steel compacts were obtained by consideration of particle size and vacuum atmosphere. Finally, for the combination of ferro-silicon and austenitic stainless steel compacts, high functionality (magnetic (1.60Tes1a) & non-magnetic) and perfect joint were obtained.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.599-600
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• 2006

This paper described the state of art of porous metal materials, the typical manufacturing technologies and performances of sintered metal porous materials, with emphasis on the recent research achievements of CISRI in development of porous metal materials. High performance porous metal materials, such as metallic membrane, sub-micron asymmetric composite porous metal, large dimensional and structure complicated porous metal aeration cones and tube, metallic catalytic filter elements, lotus-type porous materials, etc, have been developed. Their applications in energy industry, petrochemical industry, clean coal process and other industrial fields were introduced and discussed.

• Journal of Magnetics
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• v.16 no.4
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• pp.413-416
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• 2011

An array of FeCo nanotubes has been successfully fabricated in the pores of porous anodic aluminum oxide (AAO) templates by wetting templates method. The morphology and structure of the nanotube array were characterized by scanning electron microscopy, transmission electron microscopy and x-ray diffraction. The average diameter of the nanotubes was about 200 nm, and the length was more than 10 ${\mu}m$. Vibrating sample magnetometer and superconducting quantum interference device were used to investigate the magnetic properties of the nanotube array. Interaction between the nanotubes has been found to be demagnetizing as expected and the switching field distribution is broad.

• 보존과학연구
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• s.23
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• pp.131-147
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• 2002

Kkonmoe relic located in Jangan-gu, Suwon-si, Gyeonggi-do Provinceis an example of the wide chronology from the Three Kingdoms Period to Joseon Dynasty. Examinations on a forged iron ax, a cast iron ax and an iron sickle excavated from this relic revealed the microstructure structure of the metal and the manufacturing technologies. Microstructure investigation was carried out with a metallurgical microscope and a Vickers hardness tester was used to measure the hardness of the micro structures. The test results show that the forged iron ax has a ferrite and pearlitestructure. It is made of low carbon steel and then carbonized to increase carbon content. After carbonization, the surface grains are reworked and the surface decarbonized. In case of the iron sickle, it is forged from low carbon steel, then carbonized and hardened, to increase overall strength. The sickle blade is carbonized and quenched after forging, resulting in afirm, solid blade. Heat treatment to remove brittleness is not applied to the cast ironartifact, which is manufactured by solidifing hypo-eutectic cast iron with a3-4% carbon content and white cast iron. All artifacts are produced from steel and subjected to a carbonization process. To increase hardness of the blade, additional heat treatment is applied.

• Nuclear Engineering and Technology
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• v.2 no.4
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• pp.279-287
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• 1970

An an element vanadium is most effective and next is noibium to strengthening the low carbon steels by small addition both on fine precipitation and five grain. The combination effect of vanadium plus niobium or vanadium plus molybdenum is much more effective than adding on element.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.504-506
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• 1995

By means of adding B into Sendust alloy (Fe-Si-Al) with state of amorphous ribbon, mechnical properties of alloy was improved effectively, and magnetic properties didn't decrease obviously. The optimum adding quantity of B is 0.015-0.03 wt%. The adding of B was thought to give rise to reduction of ordering degree of $Fe_{3}(Si,Al)$ phase of Sedust alloy(Fe-Si-Al-B) and result in improvment of embrittlement of this alloy.

• Corrosion Science and Technology
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• v.2 no.1
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• pp.26-29
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• 2003

This study determined that the four corrosive characters of carbon steel in the marine splash zone (MSZ) in China's four sea areas. It has a range and a corrosion peak value. The rust in the MSZ plays the role of "depolarizer" in the cathodic process of corrosion. The growth law of the rust layer in MSZ has a character of "annual ring". In addition the reasons causing serious corrosion of carbon steel in the marine splash zone has been discussed in this paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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• pp.1813-1819
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• 2012

This paper presents vector magnetic properties of an electrical steel sheet (ESS) employed for electric machine and iron loss analysis considering the vector magnetic properties of the ESS. The vector magnetic properties of the ESS are measured by using a two-dimensional single sheet tester and modeled by an E&S vector hysteresis model to be applied to finite element method. The finite element analysis considering the vector magnetic properties is applied to iron loss analysis of a three-phase induction motor model, and the influences of the vector magnetic properties on the iron loss distribution are verified by comparing with numerical results from a typical B-H curve model.