• Journal of the Korean Society of Industry Convergence
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• v.9 no.3
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• pp.183-190
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• 2006

Generally, application of steel pile as deep foundation member needs specials requirement for the connection method between steel pipe and concrete footing. To investigate real compressive behavior of connection member between steel pipe pile and concrete footing, three specimens were tested with carefully designed experimental system. Main test variable is the connection method between steel pipe pile and concrete footing. The bolted bonding method and hook bonding method was considered as the connection method in this study. From the test results gained from experiment, it was conformed that two types of connection method have the almost same compressive resistance capacity. Therefore, we can conclude that these two connection methods can be used as the strengthening method to verify the compressive composite action of concrete and steel pipe pile.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.11
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• pp.45-54
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• 2018

The primary objective of this study is to develop a conceptual design of all-in-one attachment based steel pipe pile cutting robot that improves the conventional work in safety, quality, convenience and productivity. For this, the following research works are conducted sequentially; 1)literature review, 2)field investigation, 3)selection of element technology for conceptual design, 4)deduction of conceptual design and its work process, 5)technical feasibility analysis of the conceptual design and its work process. As a result, leveling laser and laser detector, plasma cutter, rotary grapple are selected as core technologies. Futhermore, a conceptual design and work process of an all-in-one attachment based steel pipe pile cutting robot are developed based on the core technologies. According to the technical feasibility analysis result, at least 76.8% of the respondents are selected positive answer about each device of the all-in-one attachment based steel pipe cutting robot. It is expected that the application range and impact on the construction industry will be enormous due to the increasing trend of the steel pipe pile market.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.216-221
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• 2004

Linepipe steels with a low carbon acicular ferrite microstructure have been recently developed to accommodate the current transportation condition of the gas and oil industry, and they are finally applied to West- East pipeline project in China. By adopting acicular microstructure, both better formability and better toughness could be obtained due to low yield ratio and fine grained microstructure. Mechanical properties of pipe are not greatly different from those of base plates or hot coils with a microstructure of acicular ferrite. Merits of introducing higher strength steels are well known, i.e., reducing the gauge of pipe and the material cost, increasing the welding speed and decreasing construction cost because of reducing the construction period. Threfore, gas and oil industry has required higher strength steel than APIX70 grade steel. Under this background, API-X80 steel has been developed and shall be applied to the several projects. In this paper, developing stage of API-X80 steel is also presented and discussed.

• Corrosion Science and Technology
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• v.16 no.2
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• pp.85-89
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• 2017

One of the most challenging issues in the oil and gas industry is corrosion assessment and management in subsea structures or equipment. At present, almost all steel pipelines are sensitive to corrosion in harsh working environments, particularly in salty water and sulphur ingress media. Nowadays, the most commonly practiced solution for a damaged steel pipe is to entirely remove the pipe, to remove only a localized damaged section and then replace it with a new one, or to cover it with a steel patch through welding, respectively. Numerous literatures have shown that fiber-reinforced polymer-based composites can be effectively used for steel pipe repairs. Considerable research has also been carried out on the repair of corroded and gouged pipes incorporated with hybrid natural fiber-reinforced composite wraps. Currently, further research in the field should focus on enhanced use of the lesser and highly explored hybrid-biocomposite material for the development in corrosion prevention. A hybrid-biocomposite material from renewable resource based derivatives is cost-effective, abundantly available, biodegradable, and an environmentally benign alternative for corrosion prevention. The aim of this article is to provide a comprehensive review and to bridge the gap by developing a new hybrid-biocomposite with superhydrophobic surfaces.

• Journal of Fisheries and Marine Sciences Education
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• v.19 no.1
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• pp.84-90
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• 2007

This paper was studied on the electrochemical corrosion characteristics of weld zone for refrigerating and heating systems pipe. Austenitic stainless steel is widely applied to various fields of industry, because it is good to corrosion resistance and mechanical properties. But STS 304 is reliable to sensitization by heat cycle on welding. Therefore, in this study, electrochemical polarization test of STS 304 steel pipe manufactured by arc welding in tap water was carried out. And then polarization resistance behavior, uniform and local corrosion behaviors of base metal(BM), weld metal(WM) and heat affected zone(HAZ) for STS 304 pipe were investigated. The corrosion current density of STS 304 steel pipe is high in order of BM(153nA/cm2) < WM(614nA/cm2) < HAZ ($1.675{\mu}A/cm2$). The pitting potential of HAZ(238mV/SCE) for STS 304 is lower than BM(1206mV/SCE) and WM(369mV/SCE). Therefore, the local corrosion like pitting corrosion, galvanic corrosion and crevice corrosion of HAZ for STS 304 is more sensitive than BM and WM.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1513-1520
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• 2009

Renewability and pollutant free energy source makes hydrogen energy popular rapidly. Hydrogen gas pressure which is after passing through reciprocating compressor part has high pulsation wave form. A unit, snubber is used as compressor components to reduce the harmful pulsation waveform and to remove the impurities in the hydrogen gas. An experiment has been conducted to investigate the pulsation reduction performance of a steel pipe used in snubber system. The amplitude of pressure reduction were varied from $0.054{\sim}0.321\;kPa$ for 10 hz to 60 hz motor speed. Compressor operation by motor with 10 to 60 hz were resulted in reduction of pressure pulsation from 16.415% to 35.151%. Pressure losses were varied from $0.001%{\sim}0.759%$, and pressure drop per centimeter of the steel pipe were varied from $0.0160{\sim}16.03\;Pa$.

• Journal of Welding and Joining
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• v.32 no.2
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• pp.4-8
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• 2014

In this research, GTA overlay welding system is developed for inside of straight pipes in various diameter. It can be applied to oil, ship building and plant industry, especially pipes connected to pressure vessels, for the purpose of cost reduction by cladding inside of pipes with corrosion and heat resistant alloys such as stainless steel or Inconel. Developed system consists of GTA power source, torch, wire feeding system, automatic arc length adjusting device, CCD camera and cooling unit. Two types of pipe inside overlay welding system are developed. One is for maximum 3m pipe length with 3 inch ~ 12 inch pipe outer diameter. Another type can be applied to maximum 12m pipe length with 7 ~ 24 inch OD. Developed system successfully produced inside cladded pipe and the results are shown through cross sectional images of the pipes.

• Proceedings of the Safety Management and Science Conference
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• 2012.04a
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• pp.301-311
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• 2012

The law(construction standard specification, construction, standard-work regulation, Industry safety standard related regulation) related to the installation of scaffolding being used commonly on the construction site is regulated that the gap of ledger is within 1.5m and first ledger is within 2m. The gap of ledger here is essential for the stability of scaffolding structure. But it is determined that it is possible for the gap of ledger is applied by explaining safety handrail as ledger, because of the fact that in current, on the construction site, safety handrail is installed with the material of scaffolding ledger as a steel tube pipe. On this study, it is aimed to guarantee the safety by analyzing the ledger of scaffolding practically and prevent the accident of manager and laborer through the actualization.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.229-232
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• 2003

In the roll forming process, a sheet or strip of metal is continuously and progressively formed into a desired cross-sectional profile by feeding it through a series of forming roll. Accordingly, it is important to maintain the material properties of the initial sheet and deform uniformly during the roll forming. The roll forming process was estimated in consideration of some factors such as material properties, strip thickness, roll diameter, roll velocity, and the deformation of the material that influence the forming length. The hydroforming technology has been recognized as a new technique in manufacturing industry, especially in automotive industry. The formed pipe in used in hydroforming process is manufactured by the roll forming. The formability during hydroforming is very sensitive to the state of pipes which are made by roll forming. Particularly the amount of hardening during roll forming affects the formability. Therefore, it is necessary to design the optimum roll flower to reduce the local hardening. In this paper, optimum roll flower which has uniform strain distribution through sheet width was obtained by comparing strain distribution in various roll flower. Finite element analysis(FEA) is performed to estimate the strain distribution related to hardening by roll forming. A numerical analysis is carried out by SHAPE-RF.

• Journal of the Korea Safety Management & Science
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• v.20 no.3
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• pp.27-36
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• 2018

The steel pipe manufacturing industry deals with facilities and materials. Especially thermal facilities are close to vapor cloud explosion (VCE) and may cause secondary damage to facilities because they deal with corrosive substances such as hydrofluoric acid, sulfuric acid and acid, fire, explosion, leakage etc. It is in danger. In this study, hazard identification method was conducted using HAZOP techniques and quantitative risk analysis was conducted using e-CA, a program that supports accident impact analysis. Equipment in the influence range of ERPG - 3 was determined to be a facility requiring replacement. It was decided that neutralization is necessary using slaked lime. Based on the cost of loss, We presented the proper replacement which is the timing of the dangerous facility. As a result, It was ideal to replace the facilities with 20 years of heat treatment facilities, one year of hydrofluoric acid storage tank, 20 years of sulfuric acid storage tank, and 5 years of hydrochloric acid storage tank.