• Corrosion Science and Technology
• /
• v.8 no.1
• /
• pp.40-43
• /
• 2009

We investigated the corrosion resistance of Zn and Cu coated steel pipes as a substitute for Cu pipe in an air-conditioner system. In addition, the galvanic corrosion tendency between two dissimilar metal parts was studied. The corrosion resistance of the Cu electroplated steel was similar to that of Cu, while the corrosion rate of the Zn electro- galvanized and the galvalume (Zn-55 % Al) coated steels was much higher and not suitable for Cu substitute in artificial sea water and acidic rain environments. Furthermore, the galvanic difference between Cu electroplated steel and Cu was so small that the Cu coated steel pipe can be used as a substitute for Cu pipe in an air-conditioner system.

• Corrosion Science and Technology
• /
• v.3 no.1
• /
• pp.20-25
• /
• 2004

In order to clarify the durability of protective coatings for maritime steel structures, various anti-corrosive organic coated steel samples were exposed for twelve years in semitropical marine environment at Miyakojima Island, Okinawa, JAPAN. Samples were various organic coated steel pipes, 4.0 m in length and 150 mm in diameter. While the bare steel pipe entirely corroded in 4.5 mm thickness in four and half years, these organic coated steel pipes exhibited protective appearances after twelve-year-exposure except for the defect in the coatings. Polyethylene (PE) lining pipe exhibited a good protective performance. Urethane painted pipe was also good but some barnacles stuck to its surface. A combination of petrolatum tape and FRP cover showed sufficient corrosion resistance for steel surface. The correlation in results between exposure and laboratory acceleration test was examined. It was found that salt spray test (SST) results corresponded to rusted area of scratched portion and that adhesion change of coating layer corresponded to the rotating immersion test result. Among the on-site measured data, volume resistivity is utilized for the index of corrosion protection performance of organic coating.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.3 s.258
• /
• pp.403-408
• /
• 2007

The concrete pipe(Hume, PC) and polyethylene(PE) pipe are usually used for dram pipe in local market. Hume pipe, however, is heavy and needs the high cost of construction and PC pipe has a disadvantage to easily occur the deformation by the outside pressure even though it is light and constructible. The corrugated steel pipe coated with polyethylene is used increasedly because it is durable, constructible and economical. However, it is not used for sewage or waste water because it is hard to guarantee the watertight property on the coupling part. In this study, we studied on the flange coupling and the method of its construction to guarantee the watertight property and easy to use. If the developed flange coupling and method are used on a construction field, the economical property, constructible property and structural safety can be guaranteed.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.37 no.4
• /
• pp.233-241
• /
• 2024

In this study, finite element analyses of coated steel pipes were conducted to research the development of sensing-based monitoring smart pipes. The coated steel pipes underwent a chemical coating pretreatment process that used modified polyethylene on both the inside and outside surfaces. Furthermore, the steel pipes were designed to minimize damage during the expansion process by incorporating connecting parts. To evaluate structural performance under various loads, four loading conditions were established: static structural analysis by earth pressure, fatigue life evaluation by vehicle load, and resistance to water leakage under both tensile and compressive loads. The analysis estimated a higher fatigue life for the developed steel pipe, compared with that of a steel pipe using ready-made epoxy coatings and joints. In addition, an average maximum displacement reduction of 56.1% and a maximum stress reduction of 61.2% were confirmed under identical conditions and diameters, thereby verifying the safety of the connecting parts of the developed coated steel pipe. Furthermore, the results of stress distribution contour analyses revealed superior water leakage resistance at the fastening parts, compared with the centers of the pipes.

• Journal of the Korean GEO-environmental Society
• /
• v.12 no.11
• /
• pp.51-57
• /
• 2011

The calcium hydroxide($Ca(OH)_{2}$) which is flowed into the deteriorated tunnel by groundwater is reacted with carbon dioxide($CO_{2}$) and the vehicle's exhaust gas ($SO_{3}$). So its by-products are precipitated at the drainage pipe and these cause the drainage clogging. Most by-products are composed of $CaCO_{3}$ with calcite from a chemical experiment. The purpose of this study is mainly focused on comparison of attachment on each material of drainage pipe (teflon-coated steel pipe, silicon-Oil coated pipe, acrylic pipe and PVC pipe). The test was progressed to disembogue the CaO aqueous solution and tunnel outflow into each of the pipes. The experimental results show that the most produced scale pipe is PVC material and the followings are Acrylic pipe, Silicon-Oil coating pipe and Teflon coating pipe. But the long-term test results showed that teflon-coated steel pipe had a problem with durability because soil which was contained in the tunnel outflow occurred detachment of coating and corrosion of the steel pipe.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.21 no.4
• /
• pp.406-414
• /
• 2001

Ultrasonic guided waves were explored to apply them to the long range inspection of polyethylene coated steel gas pipes. The steel pipes have such dimensions as 190.7mm inside diameter and 5.3mm thickness. The outside surface of the pipe is coated by a polyethylene layer of $1.9{\pm}0.5mm$ thickness. Non-axisymmetric guided waves were excited on the outside surface of the polyethylene coated pipe by using a 0.5MHz transducer with a variable angle shoe. Frequency and phase velocity tuning was used to find optimum guided wave modes for the inspection. The dispersive characteristics of the modes were analyzed in time-frequency representation obtained by short time Fourier transforms. Sample results were presented for artificial defects such as wall thinning and hole.

• Journal of Korean Society on Water Environment
• /
• v.20 no.2
• /
• pp.163-169
• /
• 2004

Feasibility of using PE sheet laminated CSP(Corrugated steel pipe) to sewers were tested via corrosion and abrasion tests for PE sheet laminated CSP; 1) corrosion test for PE film and PE coated plate, 2) corrosion test for joint of PE sheet laminated CSP, 3) corrosion test for outside of PE sheet laminated CSP, and 4) abrasion test for inside of PE sheet laminated CSP. The results for the corrosion and abrasion tests are as follows. 1. Results for corrosion tests on PE films and zinc coated steel plates that were coated with PE films show that the surfaces of both PE were not changed compared to those of original PE samples. Furthermore, PE films maintained strong adhesion on the steel plates even though they were exposed to sewage and seawater provided cutting planes of the steel plates were treated with molding. But, results for corrosion tests on the spots that were previously cut off by a knife and a cutting planes of the steel plates were treated without molding show that steel plates have been corroded if they were exposed to sewage and seawater. 2. Results for corrosion tests on joints of PE sheet laminated corrugated steel using sewage show that gathering rust was observed at cutting plane of PE sheet laminated corrugated steel after 180 days, but PE film was not flaked off. However, PE film at cutting plane was flaked off when PE sheet laminated corrugated steel was exposed to seawater. Furthermore, flaking process was severely progressed at lockseam points of which the surfaces were not smooth. 3. Results for laying PE sheet laminated corrugated steel under the ground show that the surface of untouched PE film was almost identical to that of original PE film. However, the spots that were previously cut off by a knife and a cutting plane of PE sheet laminated corrugated steel have flaked off. 4. As a result of abrasion tests conducted with PE sheet laminated corrugated steel and sand, brilliance and thickness of PE was not greatly changed under the severe abrasion conditions. Therefore, the durability of PE sheet laminated corrugated steel for abrasion was determined to be good.

• Nuclear Engineering and Technology
• /
• v.54 no.4
• /
• pp.1185-1194
• /
• 2022

The maintenance of condenser main pipe is the key to achieve film-forming amine maintenance effectiveness. In this work, oxygen content, pH and temperature of the solution were controlled to simulate the condition of condenser main pipe, and magnetite coated carbon steel sample was prepared by pre-oxidization. CAM was used to characterize the hydrophobicity of film formed samples. Hydrophobic film was formed on pre-oxidized carbon steel samples when octadecylamine concentration reaches 20 mg/kg. SEM, EDS, EIS, and PD were used to characterize the influence of octadecylamine concentration on maintenance effectiveness. It was found that the maintenance effectiveness was enhanced and the corrosion rate was suppressed with the increase of octadecylamine concentration. FIB and TEM were used to detect the adsorbed octadecylamine film thickness founding that octadecylamine adsorbed onto the surface of pre-oxidized carbon steel by multi-layer adsorption mechanism.

• Proceedings of the KIEE Conference
• /
• 2004.11a
• /
• pp.227-229
• /
• 2004

The corrosion rate of buried steel pipes for water works was investigated under soil environment. Steel pipe shows various characteristics caused by complicated environment condition of underground and especially the corrosion rate of it depends on the resistivity of soil controlled by content of water. In this paper, the corrosion behavior of steel pipe was observed by polarization test under soil and the silica sand in the water content range of 0-50%. Generally it is well known that the resistivity of soil decreased rapidly over 15% water content. In fact the corrosion rate, corrosion potential, and corrosion consumption (MPY) of steel pipe were shown very different aspects within 20% water content.

• Journal of the Korean Institute of Gas
• /
• v.20 no.5
• /
• pp.112-117
• /
• 2016

The standard(KS D 3631) should be obey for using fuel gas pipe in Korea and a carbon steel pipe is coated with synthetic resine for protecting the corrosion. The coating is just performed for anti-corrosion, and actual strength of pipe is given by the carbon steel pipe when the fuel gas is transported. When the flaws are occurred in the steel pipe, the estimation method which is used for residual strength is necessary. But the suitable method is not exist for applying the fuel gas pipe. Eventually, the residual strength is estimated by overseas regulation such as ASME B31G or DNV RP F101. But the method based on the relative regulations are not sufficiently valid and it can not estimate the 85% over even. Therefore, the test was performed for validation with pipe specimen. The specimen was made with artificial flaw. The test results showed the certain differences according to flaw depth and DNV RP F101 is suitable to estimate the residual strength in Korea. The results in this paper contain in case of the severe flaw depth and suitable mode for Korea, so the result can be expected as valuable and widely used in various field.