An Analysis on the Competitiveness of Japanese Steel Products in Korea: Focus on the Structural Changes of Supply and Demand in Korea Steel Industry

Seoung-Taek Lee 한국무역학회 2021 Journal of Korea trade Vol.25 No.4

Purpose - This study reviews changes in the steel export-import structure between Korea and Japan to strengthen the competitive advantage of the Korea Steel industry using a trade-related index. Design/methodology - This study focuses on analyzing comparative advantage based on the trade intensity index (TII), revealed comparative advantage index (RCA), and trade specialization index (TSI). Findings - Korea’s steel import from Japan increased due to the domestic supply shortage of HR (Hot Rolled Coil) and Plate, rather than the sharp decline of the domestic steel industry’s competitiveness in 2010. However, after the completion of Hyundai Steel’s blast furnace, the Korea Steel industry solved the supply shortage. Additionally, the import of Japanese steel products had decreased significantly from 2009 to 2019. Originality/value - This study attempts to analyze Japanese steel products’ competitiveness in trade and the domestic influence of high-quality Japanese steel products. These results are connected to domestic steel supply and demand structure and relations with the Japanese steel industry. After completing Hyundai Steel’s blast furnace, the Korea Steel industry solved the supply shortage, and the import of Japanese steel products has decreased significantly from 2009 to 2019.

A New Steel Jacketing Method for Concrete Cylinders and Comparison of the Results with a Constitutive Model

Eunsoo Choi,Man-Cheol Kim 한국철도학회 2008 International Journal of Railway Vol.1 No.2

A New Steel Jacketing Method for Concrete Cylinders and Comparison of the Results with a Constitutive Model

Choi, Eun-Soo,Kim, Man-Cheol The Korean Society for Railway 2008 International Journal of Railway Vol.1 No.2

This paper introduces a new steel jacketing method for reinforced concrete columns with lap splice and evaluates its performance by a series of axial tests of concrete cylinders. At first, 45 concrete cylinders were fabricated with varying the design compressive strengths of 21, 27 and 35 MPa and, then, the part of them was jacketed with two-split-steel jackets under lateral confining pressure. The parameters in the first test were the steel jacket's thickness and the existence of adhesive between steel and concrete surface. In the second test, whole steel jackets were used to wrap cylinders with lateral pressure. Also, a double-layer jacket consisted of two steel plates was introduced; a cylinder was jacketed by two steel plates one after another. The effect of the new method was verified through comparing the results of the compressive tests for plain and jacketed cylinders. The steel jacket built following the new method showed good results of increasing the compressive strength and ductility of the jacketed cylinders with respect to the plain cylinders. The thicker steel jackets showed the more increased compressive strength, and the ductility at failure depended on the welding quality on steel jackets. The adhesive between steel and concrete surface reduced the confining effect of the steel jackets. The whole jacket showed more ductile behavior than the two-split jackets. The double-layered jackets were estimated to possess an equal performance to that of a single steel jacket having the same thickness of the double-layered jacket. Finally, the experimental results were compared with the constitutive model of steel-jacketed concrete; which showed a good agreement between the experimental results and the models.

The Research on the Sustainable growth of Listed Companies in Chinese Steel Industry

LI Gui rong,WANG Wei 한국경영교육학회 2012 한국경영교육학회 학술발표대회논문집 Vol.2012 No.6

Steel industry is one of the important raw materials industries in China. In the Ministry of Industry and Information Technology, steel industry is included in the plan for ten big industries to be adjusted and developed, which shows its important position in the national economy. In the first 10 years of this century, continuous and extraordinary growth is a prominent feature of China's steel industry. Between the year 2000-2010, steel production has rose from 127 million tons to more than 600 million tons, an increase of about 4 times, which built a solid foundation for a big steel country and made China a veritable big country famous for steel production. At the same time, the rapid development of China's steel industry has also resulted in tremendous energy and resource consumption, which influences the industry's sustainable growth and hinder Chinato become a powerful country of iron and steel based on qualitative and quantitative standards. Extensive growth mode, merely pursuing the increase of quantity, is not desirable. It is very important for China to seek a sustainable growth pattern for steel industry. This paper studies sustainable growth of China's steel industry from a financial point of view, which will contribute to systematically analyze the sustainable growth of the listed companies in China, to identify the problems and make more evidence-based, sensible decisions in marketing, finance and manufacturing. Also, the studies can provide timely guidance for the growth strategies of other steel companies which have been listed, to be listed, and other small and medium enterprises to promote their healthy and stable developments. And it will lay a solid foundation for the sustainable development of China's steel industry and plays an important role for China in becoming a powerful country of iron and steel.Based on the theory of enterprises' sustainable development, this essay has made a comparative analysis on typical models of sustainable growth and analyzed the internal and external factors affecting listed companies' sustainable growth. Based on the development status of listed companies in China's steel industry, this essay selected 33 companies in the steel industry listed in Shanghai and Shenzhen Stock Exchange before 2006 after removed those having special conditions, such as "ST" companies whose stock exchanges were specially treated because of consecutive losses, and companies experienced a major business restructuring, etc. With the Robert Higgins' sustainable growth model, we tested the sustainable growth of the selected listed companies in the steel industry between 2006-2010 by using Wilcoxon's signed rank test. The empirical results show that the samples have not achieved sustainable growth whether as a whole or separated year by year. We also concluded that there was a increasing gap between the real growth rates and the sustainable growth rates in five years, which indicated that it was very serious for these companies to blindly pursue high-speed growth, and the financial sustainable growth in the steel industry has not got enough attentions in these companies. So it is not optimistic to achieve sustainable growth for listed companies in the steel industry.

Analysis on Extension Length of Shape Steel in Transfer Columns of SRC–RC Hybrid Structures

Kai Wu,Jianyang Xue,Yang Nan,Hong-tie Zhao 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.3

Seismic performance of SRC–RC transfer column was analyzed based on the experiment of 16 transfer columns specimens under low cyclic reversed loading, which mainly focus on the extension length of shape steel. Analysis of ductility, bearing capacity, energy dissipation capacity and degeneration ratio of strength were completed. Displacement ductility promotes at fi rst and then reduces with increasing of extension length of shape steel, reaching the peak value when extension length gets close to three fi fths of column height. Extension length of shape steel has little eff ect on bearing capacity, while energy dissipation capacity of transfer columns is infl uenced by many factors. Three fi fths of column height is the rational extension length of shape steel, of which specimens have advanced in energy dissipation, good stability of stiff ness and strength. The bond performance between concrete and shape steel decreases with the increasing of extension length of shape steel, and hence the stability of strength decreases. Minimum extension length of shape steel was confi rmed and the calculation method was proposed, which is mainly used to ensure the bend yielding of shape steel at bottom section. Moment at the truncation section leads to pull-out eff ect of steel bars, which enhances with increasing of the moment and section ratio of shape steel. Contrafl exure point is at three fi fths of column height. If the shape steel extends to contrafl exure point, moment of steel truncation section will reach minimum. So the reduce the concrete damage with better deformation ability and mechanical behavior of transfer column.

Experimental assessment on flexural behavior of demountable steel-UHPC composite slabs with a novel NPR steel plate

Jin-Ben Gu,Jun-Yan Wang,Yi Tao,Qingxuan Shi 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.49 No.4

This study experimentally investigates the flexural behavior of steel-UHPC composite slabs composed of an innovative negative Poisson’s ratio (NPR) steel plate and Ultra High Performance Concrete (UHPC) slab connected via demountable high-strength bolt shear connectors. Eight demountable composite slab specimens were fabricated and tested under traditional four-point bending method. The effects of loading histories (positive and negative bending moment), types of steel plate (NPR steel plate and Q355 steel plate) and spacings of high-strength bolts (150 mm, 200 mm and 250 mm) on the flexural behavior of demountable composite slab, including failure mode, load-deflection curve, interface relative slip, crack width and sectional strain distribution, were evaluated. The results revealed that under positive bending moment, the failure mode of composite slabs employing NPR steel plate was distinct from that with Q355 steel plate, which exhibited that part of highstrength bolts was cut off, part of pre-embedded padded extension nuts was pulled out, and UHPC collapsed due to instantaneous instability and etc. Besides, under the same spacing of high-strength bolts, NPR steel plate availably delayed and restrained the relative slip between steel plate and UHPC plate, thus significantly enhanced the cooperative deformation capacity, flexural stiffness and load capacity for composite slabs further. While under negative bending moment, NPR steel plate effectively improved the flexural capacity and deformation characteristics of composite slabs, but it has no obvious effect on the initial flexural stiffness of composite slabs. Meanwhile, the excellent crack-width control ability for UHPC endowed composite members with better durability. Furthermore, according to the sectional strain distribution analysis, due to the negative Poisson's ratio effect and high yield strength of NPR steel plate, the tensile strain between NPR steel plate and UHPC layer held strain compatibility during the whole loading process, and the magnitude of upward movement for sectional plastic neutral axis could be ignored with the increase of positive bending moment.

Axial capacity of back-to-back built-up cold-formed stainless steel unlipped channels-Numerical investigation and parametric study

Krishanu Roy,Hieng Ho Lau,Zhiyuan Fang,Abdeliazim Mustafa Mohamed Ahmed,James B.P. Lim 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.5

In cold-formed steel structures, such as trusses, wall frames and portal frames, the use of back-to-back built-up cold-formed stainless steel unlipped channels as compression members are becoming popular. The advantages of using stainless steel as structural members are corrosion resistance and durability, compared with carbon steel. Current guidance by the American Iron and Steel Institute (AISI) and the Australian and New Zealand (AS/NZS) standards for built-up carbon steel sections describes a modified slenderness approach, to consider the spacing of the intermediate fasteners. The AISI and AS/NZS do not include the design of stainless-steel built-up channels and very few experimental tests or finite element (FE) analyses have been reported in the literature for such back-to-back cold-formed stainless steel unlipped channel section columns. This paper presents a numerical investigation on the behavior of back-to-back built-up cold-formed stainless steel unlipped channel section columns. Three different grades of stainless steel i.e., duplex EN1.4462, ferritic EN1.4003 and austenitic EN1.4404, were considered. The effects of screw spacing on the axial strength of such built-up unlipped channels were investigated. As expected, most of the short and intermediate columns failed by either local-global or local-distortional buckling interactions, whereas the long columns failed by global buckling. All three grades of stainless-steel stub columns failed by local buckling. A comprehensive parametric study was then carried out covering a wide range of slenderness and different cross-sectional geometries to assess the performance of the current design guidelines of carbon steel built-up sections in accordance with the AISI and AS/NZS. In total, 647 FE models were analyzed. From the results of the parametric study, it was found that the AISI and AS/NZS are conservative by around 14 to 20% for all three grades of stainless steel built-up unlipped channel section columns failed through global buckling. However, the AISI and AS/NZS carbon steel design rules can be un-conservative by around 8 to 13%, when they are used to calculate the axial capacity of those stainless steel built-up unlipped channels which are failed in local buckling.

Micro-Steel Fiber-Reinforced Self-compacting Concrete-Filled Steel-Tube Columns Subjected to Axial Compression

S. M. Imam Shah,G. Mohan Ganesh 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.4

Experimental and analytical investigations of steel-tube specimens filled with micro-steel-fiber-reinforced self-compacting concrete are presented in this study. The purpose of this study was to investigate the influence of micro-steel fibers on the strength and behavior of concrete-filled steel-tube (CFST) specimens with different wall thicknesses, length/diameter (L/D) ratios, and micro-steel fibers. Because concrete has weak tensile properties, the use of steel fibers is essential for enhancing the strain-softening characteristics. Hence, crimped micro-steel fibers with an aspect ratio of twenty-five were blended with self-compacting concrete and used as the infill for the CFST specimens. Sixty-four CFST specimens with thicknesses of 2 and 3 mm and L/D ratios of 3, 4, 5, and 6, along with micro-steel fibers with volume percentages of 0%, 0.5%, 1.0%, and 1.5%, were subjected to axial compression. The failure report includes the following modes of failure: ultimate capacities, deformation curves accompanying the effect of parameters such as the strength index, percentage of contribution of steel and concrete, confinement effect, and ductility index on the axial capacity of the CFST columns. The results indicated that the use of micro-steel fibers enhanced the ultimate capacity and ductility as well as delayed the local buckling of the specimens. The ultimate capacities of the columns were compared using design codes, such as the Eurocode (EC4), Australian code (AS5100), American code (AISC 360-10), American Concrete Institute (ACI-318), and Chinese code (DBJ13-51). An equation was proposed to determine the axial capacity, and the predicted results were close to the experimental test results and experimental data collected from 93 CFSTs in previous studies. The failure mechanism, buckling patterns, and deformation curves of all specimens were examined using the ABAQUS/CAE software, and the results were consistent with the experimental results.

Experimental investigation of carbon steel and stainless steel bolted connections at different strain rates

Yancheng Cai,Ben Young 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.30 No.6

A total of 36 carbon steel and stainless steel bolted connections subjected to shear loading at different strain rates was experimentally investigated. The connection specimens were fabricated from carbon steel grades 1.20 mm G500 and 1.90 mm G450, as well as cold-formed stainless steel types EN 1.4301 and EN 1.4162 with nominal thickness 1.50 mm. The connection tests were conducted by displacement control test method. The strain rates of 10 mm/min and 20 mm/min were used. Structural behaviour of the connection specimens tested at different strain rates was investigated in terms of ultimate load, elongation corresponding to ultimate load and failure mode. Generally, it is shown that the higher strain rate on the bolted connection specimens, the higher ultimate load was obtained. The ultimate loads were averagely 2-6% higher, while the corresponding elongations were averagely 8-9% higher for the test results obtained from the strain rate of 20 mm/min compared with those obtained from the lower strain rates (1.0 mm/min for carbon steel and 1.5 mm/min for stainless steel). The connection specimens were generally failed in plate bearing of the carbon steel and stainless steel. It is shown that increasing the strain rate up to 20 mm/min generally has no effect on the bearing failure mode of the carbon steel and stainless steel bolted connections. The test strengths and failure modes were compared with the results predicted by the bolted connection design rules in international design specifications, including the Australian/New Zealand Standard (AS/NZS4600 2018), Eurocode 3 - Part 1.3 (EC3-1.3 2006) and North American Specification (AISI S100 2016) for cold-formed carbon steel structures as well as the American Specification (ASCE 2002), AS/NZS4673 (2001) and Eurocode 3 - Part 1.4 (EC3-1.4 2015) for stainless steel structures. It is shown that the AS/NZS4600 (2018), EC3-1.3 (2006) and AISI S100 (2016) generally provide conservative predictions for the carbon steel bolted connections. Both the ASCE (2002) and the EC3-1.4 (2015) provide conservative predictions for the stainless steel bolted connections. The EC3-1.3 (2006) generally provided more accurate predictions of failure mode for carbon steel bolted connections than the AS/NZS4600 (2018) and the AISI S100 (2016). The failure modes of stainless steel bolted connections predicted by the EC3-1.4 (2015) are more consistent with the test results compared with those predicted by the ASCE (2002).

Cyclic behaviour and modelling of stainless-clad bimetallic steels with various clad ratios

Xinpei Liu,Huiyong Ban,Juncheng Zhu,Brian Uy 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.34 No.2

Stainless-clad (SC) bimetallic steels that are manufactured by metallurgically bonding stainless steels as cladding metal and conventional mild steels as substrate metal, are kind of advanced steel plate products. Such advanced composite steels are gaining increasingly widespread usage in a range of engineering structures and have great potential to be used extensively for large civil and building infrastructures. Unfortunately, research work on the SC bimetallic steels from material level to structural design level for the applications in structural engineering field is very limited. Therefore, the aim of this paper is to investigate the material behaviour of the SC bimetallic steels under the cyclic loading which structural steels usually could encounter in seismic scenario. A number of SC bimetallic steel coupon specimens are tested under monotonic and cyclic loadings. The experimental monotonic and cyclic stress-strain curves of the SC bimetallic steels are obtained and analysed. The effects of the clad ratio that is defined as the ratio of the thickness of cladding layer to the total thickness of SC bimetallic steel plate on the monotonic and cyclic behaviour of the SC bimetallic steels are studied. Based on the experimental observations, a cyclic constitutive model with combined hardening criterion is recommended for numerical simulation of the cyclic behaviour of the SC bimetallic steels. The parameters of the constitutive model for the SC bimetallic steels with various clad ratios are calibrated. The research outcome presented in this paper may provide essential reference for further seismic analysis of structures fabricated from the SC bimetallic steels.