• Proceedings of the KSME Conference
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• 2001.06a
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• pp.231-236
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• 2001

A newly developed Advanced Indentation System (AIS), which is a portable and nondestructive system for evaluating tensile properties, was used to measure mechanical behavior of materials used under high temperature and pressure conditions. This test measures indentation load-depth curve during indentation and analyzes the mechanical properties related to deformation and fracture. Aging effects of Cr-Mo and Cr-Mo-V steel at high temperature were simulated. Tensile properties including yield strength and tensile strength at various temperature are obtained from the test. For all test materials and conditions, the AIS-derived results were in good agreement with those from conventional standard test method. Examples of the test results ate given and potential applications of the AIS to assess the integrity of aging structures are briefly discussed.

• Corrosion Science and Technology
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• v.11 no.1
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• pp.15-19
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• 2012

Both electrogalvanized and hot-dip galvanized steel sheets have been finally produced via organic-inorganic surface coating process on the zinc surface to enhance corrosion resistance and afford additional functional properties. Recently, POSCO has been developed a variety of chromate-free coated steels that are widely used in household, construction and automotive applications. New organic-inorganic hybrid coating solutions as chromate alternatives are comprised of surface modified silicate with silane coupling agent and inorganic corrosion inhibitors as an aqueous formulation. In this paper we have prepared new type of hybrid coatings and evaluated quality performances such as corrosion resistance, spot weldability, thermal tolerance, and paint adhesion property etc. The electrogalvanized steels with these coating solutions exhibit good anti-corrosion property compared to those of chromate coated steels. Detailed components composition of coating solutions and experimental results suggest that strong binding between organic-inorganic hybrid coating layer and zinc surface plays a key role in the advanced quality performances.

• Journal of the Korean institute of surface engineering
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• v.36 no.2
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• pp.176-184
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• 2003

New lubricant film of organic and inorganic composite resin was developed to improve the press formability of galvannealed steel sheets (GA) for automotive body panels. The frictional coefficient of lubricant GA steel sheets is about 20% superior to that of uncoated GA. The current range of spot welding of lubricant GA is similar to that of the uncoated GA, but the burning trace of spot welding is inferior to that of the uncoated GA in the oiling condition. The alkaline degreasability of lubricant GA shows 100% in alkaline degreasing condition of automotive company. The size and shape of the phosphated coating layer are similar to those of the uncoated GA sheet. The powdering property of the lubricant GA gives rise to 20∼50% improved property compared with the uncoated GA sheet.

• Journal of Advanced Marine Engineering and Technology
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• v.13 no.2
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• pp.64-77
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• 1989

In this study, the experiments were carried out for the purpose of establishment of aluminium cementation to steel surface by diffusible heat treatment after making the coated film onto the substrate by arc spray method. Also, the microstructure and mechanical properties of the cementation layer produced by this study were inspected for various heat treatment and spraying conditions. Main results obtained are as follow ; 1. The coating film characteristics which have excellent errosion-resistance, high temperature oxidation-resistance are obtained by aluminium penetration heat treatment after making the sprayed aluminum coating film onto the steel substrate. 2. Aluminium diffusion penetration takes place at higher temperature than 660.deg.C, and the more heat treatment time and the higher heat treatment temperature adopted, the deeper diffusion layer obtained. 3. Insert gas arc spraying using argon gas as the carrier gas higher improvement of mechanical property than that of compressed air environment. 4. The coating film characteristics appeared to be improvement of adhesive property, porosity plugging effect by heat treatment in air environment.

• Corrosion Science and Technology
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• v.5 no.5
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• pp.153-159
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• 2006

Austenitic stainless steels with addition of various amounts of Mo and W were evaluated in terms of corrosion and contact resistance to determine optimum alloy composition of metallic bipolar plate for PEMFC. The corrosion property was evaluated by both acid fume exposure test at $130^{\circ}C$ and by electrochemical polarization tests in $H_3PO_4$ solution at $80^{\circ}C$. Austenitic stainless steel with proper amount of Mo and W demonstrated not only good corrosion resistance but also low contact resistance. Analyses on the passive film show that partial substitution of Mo by W enhances passive film stability and repassivation property. Test results suggest that austenitic stainless steel with 2 wt%Mo and 4 wt%W has optimum composition for metallic bipolar plate used in PEMFC.

• Journal of the Korean institute of surface engineering
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• v.36 no.5
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• pp.398-405
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• 2003

The stainless steel wire requires good corrosion resistance and mechanical properties, such as drawing ability, combined with a high resistance to corrosion. For increasing drawing ability of stainless steel, Ni coating methods have been used in this study. However, there is no information on the electrochemical corrosion behavior of drawed wires after Ni coating. To investigate corrosion resistance and mechanical property of drawed wire, the characteristics of Ni coated wires have been determined by tensile strength tester, hardness tester, field emission scanning microscope, energy dispersive x-ray analysis and potentiodynamic method in 0.1 M HCl. The drawed stainless steel wires showed the strain-induced martensitic structure, whereas non-drawed stainless steel wire showed annealing twin in the matrix of austenitic structure. The hardness and tensile strength of drawed stainless steel wire were higer than that of non-drawed stainless steel wire. Electrochemical measurements showed that, in the case of drawed stainless steel o ire after Ni coating, the corrosion resistance and pitting potential increased compared with non-coated and drawed stainless steel wire due to decrease in the surface roughness.

• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.1032-1039
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• 2002

Since recycling waste glass as a material for concrete has a great advantage environmentally and economically, the US, Japan and other countries have started recycling waste glass widely and accumulating the technology of manufacturing equipment and its construction. However, there is no practical data on the mechanical property of concrete using waste glass. In this study, the mechanical property of the steel fiber reinforced concrete using waste glass was analyzed in terms of waste glass content(20vo1. ％, 40vo1. ％ as a part of fine aggregate) and steel fiber content(0.5~ 1.5vol.％). The results of this study are as follows : The workability of the concrete including steel fiber and waste glass decreases, as the inclusion rate of waste glass and steel fiber increases. The tensile strength, flexural strength and flexural toughness of the concrete including waste glass increase considerably, as the inclusion rate of steel fiber increases. From the results, the appropriate inclusion rate of steel fiber and waste glass is thought to be 1.0vol. % and 20vo1. ％, respectively.

• 한국기계연구소 소보
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• s.11
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• pp.39-46
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• 1984

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.261-267
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• 2004

Current steel makers are trying to develop new manufacturing process to secure price competition and to improve productivity by testing a various kinds of rolling condition of several kinds of steel at TCM. Accordingly, Reverse Mill operation for Stainless steel is changing to TCM operation and furthermore, even general carbon steel and electric steel plate are requested to be worked at TCM simultaneously. By these changing of rolling condition, it become to be necessary to develop new water-soluble cold rolling oil that has a characteristics to be suitable for various working condition and in this report, we would like to mention lubrication condition to fulfill requested characteristics of each steels and development and applying result of multi-purpose water-soluble cold rolling oil which has such an lubrication property.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.06a
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• pp.99-118
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• 1994

In recent years reduction in noise and vibration in automobile has been strongly required not only from the standpoint of environmental regulations but also for raising the commercial value and ride comfort. Vibration damping steel sheets, which are composites made by sandwitching a visco-elastic resin layer between two steel sheets, have been developed as effective noise-abating materials and have found a growth of use in automobile industries. Vibration damping steel sheets for commercial use must be excellent in vibration damping property, press formability and spot weldability, but are inferior to ordinary steel sheets. In this study, the mechanical properties of vibration damping steel are evaluated, and press formability is analysed on the basis of those properties and shear bonding strength. The development of engine oil pan using damping steel sheets are also reported, focusing on serious problems in oil pan drawing.