• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.202-203
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• 2018

Chemistry and microstructure of steel reinforcement bars play an important role to control the corrosion in concrete environments. In present study, we have chosen two different microstructure of steel rebars produced from companies and assessed their corrosion characteristics in simulated concrete pore (SCP) solution with prolonged exposure periods. Hot rolled steel rebar showed more corrosion resistance compare to thermo-mechanically treated (TMT) one. The growth of passive is greater in hot rolled (A) than TMT (B) due to orientation of microstructure. TMT steel rebar exhibit distorted microstructure with many micro cells which enhances the galvanic coupling and induce the deterioration while on the other hand hot rolled rebars exhibit fine grain boundary which responsible in growth of uniform, adherent and protective passive film resultant improved impedance was observed.

• Journal of Welding and Joining
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• v.27 no.6
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• pp.36-42
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• 2009

In the present day, new performances are demanded for automobile body steel sheet for example, light weight, durability, resistance corrosion and environmental protection. For an improvement of resistance corrosion, European automobile companies developed pre-sealed steel in 1990's. Pre-sealed steel have organic coated layer upper zinc coated layer. Evaluating a resistance spot weldability of pre-sealed steel plate is important because resistance spot welding is used mainly in automobile body joining process. In this study, evaluating a weldability of pre-sealed steel plate was carried out using lobe diagram, dynamic resistance and high-speed image. Usually, Pre-sealed steel has poor weldability than GA steel's. To improve a weldability of pre-sealed steel sheet, pre-current was applied to welding process. Pre-current is applied prior to base-current. In conclusion, the weldability of pre-sealed steel has been improved than GA steel's by applying pre-current.

• Korea Trade Review
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• v.45 no.1
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• pp.173-201
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• 2020

As the US's trade deficit with China and China's manufacturing industry has risen rapidly, the US has begun to regulate trade items as part of China's checks. Four rounds of reprisal measures have greatly altered the trade structures of both countries. In particular, Korea, which is highly dependent on the US and China, has been directly affected by US-China trade disputes. The purpose of this study was to analyze the effects of US-China trade disputes on the stock price of Korean export firms by performing an event study. This study analyzed stock price fluctuations for 7 days before and after entry into forced [Please check] retaliatory tariffs on Korean exporters' export items subject to retaliatory tariffs. According to the analysis results, among companies that produce goods with major tariffs imposed on China by the US, such as electronic appliances, semiconductors, machinery, and automobiles, those producing electronics and semiconductor products were positively affected by the tariff incident. Secondly, among the companies producing steel, chemicals, and machinery, which the main tariffs imposed by the United States, companies producing steel and chemicals were negatively affected by the incident due to the stagnation of trade between China and the US. The results of this study suggest future trade policy directions for Korea and help to establish an export strategy for major industries.

• Korea Trade Review
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• v.44 no.5
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• pp.127-142
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• 2019

As Korea's steel industry exports 38 percent of its total steel production, the future management environment of the steel industry will change depending on the outcome of the FTA negotiations. The overall industrial structure of the domestic steel industry depends on the rules of origin, which are directly linked to the effect of concessionary tariffs. Therefore, negotiations on rules of origin are as important as tariff liberalization for Korea's steel industry. Korea's cold-rolled and plated companies are expected to be negatively affected as the country of origin standards of steel products have not considered the steel production processes in Korea. In future FTA talks, the country of origin rules should be agreed on a change of tariff classification basis. This result would secure a stable export market through increased predictability of steelmakers and reduce the risk of increased costs of oil and intangible products. In addition, the government should consider the structure of domestic supply and demand so that it does not impose constraints on the change of tariff classification. Finally, participants in the negotiations should consider the opinions of the domestic steel industry.

• Corrosion Science and Technology
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• v.17 no.4
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• pp.193-201
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• 2018

In order to suppress $CO_2$ emission and protect passengers in case of vehicle collision, continuous efforts are being made to increase the application ratio and tensile strength of advanced high strength steels used in the manufacturing of automotive body. Simultaneously, hydrogen embrittlement which was not a concern in the past has currently become a major issue due to microstructure that is sensitive to hydrogen uptake. The sensitivity increases with residual stress and hydrogen uptake content. Many automotive OEM companies and mill makers are setting specifications to control hydrogen embrittlement. The factors which lead to hydrogen embrittlement are material sensitivity, residual stress, and hydrogen concentration; researches are in progress to develop countermeasures. To reduce material sensitivity, mill makers add high energy trap elements or microstructure refinement elements. Automotive OEM companies design the car parts not to concentrate local stress. And they manage the levels to not to exceed critical hydrogen concentration. In this article, we have reviewed hydrogen embrittlement evaluation methods and corresponding solutions that are being studied in automobile manufacturing industries and mill makers.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.1
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• pp.142-149
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• 1999

A machine frame has been manufactured by casting. However, due to the development of the industrial society, 3-D duties was refused. Especially, the declination of the casting industry makes it difficult to produce the frame. Many companies still manufacture the small casting products. The large casting products are extremely limited and manufactured for their own use. Therefore, it is difficult to keep the term of order. In this study, the characteristics of steel structure which is produced by welding were identified in the view of mechanical strength of steel structure which is produced by welding were identified in the view of mechanical strength to substitute steel structure for casting frame. But welding structure has the residual stress, HAZ and welding deformation. Residual stress and HAZ especially cause crack growth. The proposed steel structure, based on the simulation and experiment(tensile curve and S-N curve), can reduce not only the producting term but also the weight of the frame.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.10-21
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• 1999

Recent progress in manufacture of hot and cold rolled steel strip products and their applications were reviewed. The main trend in the technological development has been to meet the customers' requests for quality improvement and cost reduction. The weight reduction to reduce the fuel consumption is the main issue in the automotive industry and, therefore, various steels have been developed to improve formability as well as strength. The steels include super-EDDQ steels, bainitic steels, TRIP steels, etc. In the oil industry, efforts have been focused to improve strength together with either low temperature toughness or HIC/SSCC resistance. The packaging industry is also a highly competitive market, and steel and canmaking companies have worked cooperatively to develop cost-effective canmaking processes as well as high performance steels. This type of cooperation has also been found important in other industries such as the appliance and electronic industries for the benefits of both steelmakers and customers.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.3
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• pp.11-22
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• 2022

The iron and steel sector is caught between two worlds: "carbon reduction" and "development." The goal of this study is to show that optimizing asset structure to boost intangible assets, particularly brand assets, is a viable strategy to achieve low-carbon development. This study uses panel data from 38 A-share companies in China's iron and steel industry from 2010 to 2020, as well as World Brand Lab data, to create a comprehensive impact index of enterprise value from the standpoint of an asset structure optimization, and to test the impact of intangible assets and brand equity on enterprise value. The findings show that: the asset structure of iron and steel enterprises is closely related to enterprise value, implying that iron and steel industry development necessitates a transformation of quantity control and quality improvement; the proportion of intangible assets in the asset structure of iron and steel enterprises plays a positive and critical role in enterprise value under surplus conditions. The iron and steel industry begins to shift from tangible to intangible assets; there is heterogeneity in the iron and steel industry transformation. Given certain technological levels, the share of brand assets contributes significantly to the increase in enterprise value.

• Management & Information Systems Review
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• v.30 no.4
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• pp.229-251
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• 2011

This paper will discuss the significance of cooperation between supply chain companies and its components. In addition, it will analyze how this effects the outcome in distribution focusing on companies in the steel pipe industry. In sum, theory 1 was chosen since as a result of hierarchical regression analysis communication, IT, partnership, and success monitoring, which are all components of the supply chain cooperation, are proven to affect the absolute distribution success positively. According to the standardized beta coefficient the most important factor for distribution success is communication, followed by IT, partnership and lastly success monitoring. Moreover, according to theory 2, communication, IT, partnership and success monitoring all affect relative distribution success positively. Most important factors are communication, IT, partnership, success monitoring. Thus, since the most crucial factor in deciding both the absolute and relative distribution success is communication, steel pipe companies are advised to execute strategic use.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.3
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• pp.279-286
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• 2015

To achieve lightweight design, research & development of various lightweighting technologies such as hydroforming are underway worldwide. In the case of hydroforming, application of ultra high strength steel is essential for weight reduction of the car. However, considering common high-strength carbon steel, it is not suitable to the actual hydroformed parts since the lack of formability. DP steel offers an outstanding combination of strength and formability as a result of their microstructure. DP steel has high strength and good formability but it's difficult to secure stable quality of welding section because of softening of weld section and chemical composition. Therefore, most of companies use LASER welding when making high strength tube. Electric resistance welding is excellent production method for steel tube manufacturing considering the productivity. Optimum electric resistance welding technology is needed to be developed for application of high strength hydroformed parts using DP steel. This study is comprehensive research & development from electric resistance welding to actual formabililty evaluation.