• Journal of the Korean institute of surface engineering
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• v.14 no.3
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• pp.142-150
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• 1981

The present paper clarified mechanism of quench crack formation in high carbon steel dur-ing quenching, and, in order to prevent the quench crack, proposed two basic guides in alloy design of high carbon tool steel. They are to raise Ms temperature of high carbon tool steel by addition of alloying elemen-ts such as Al and Co, and to decrease grain size of the carbon tool steel by addition of alloying elements of Al, B, Ti, Zr, and V, and by grain-refining heat treatment.

• Journal of Powder Materials
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• v.20 no.4
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• pp.291-296
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• 2013

SKD11 (ASTM D2) tool steel is a versatile high-carbon, high-chromium, air-hardening tool steel that is characterized by a relatively high attainable hardness and numerous, large, chromium rich alloy carbide in the microstructure. SKD11 tool steel provides an effective combination of wear resistance and toughness, tool performance, price, and a wide variety of product forms. The CNTs was good additives to improve the mechanical properties of metal. In this study, 1, 3 vol% CNTs was dispersed in SKD11 matrix by mechanical alloying. The SKD11+ CNT hybrid nanocomposites were investigated by FE-SEM, particle size distribution, hardness and wear resistance. The CNT was well dispersed in the SKD11 matrix and the mechanical properties of the composite were improved by CNTs addition. It shows good feasibility as cold work die tool.

• Journal of Powder Materials
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• v.22 no.3
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• pp.157-162
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• 2015

SKD11(ASTM D2) tool steel is a versatile high-carbon, high-chromium, air-hardening tool steel that is characterized by a relatively high attainable hardness and numerous, large, chromium rich alloy carbide in the microstructure. SKD11 tool steel provides an effective combination of wear resistance and toughness, tool performance, price, and a wide variety of product forms. Adding of CNTs increased the performance of mechanical properties more. 1, 3 vol.% CNTs was dispersed in SKD11 matrix by mechanical alloying. SKD11 carbon nanocomposite powder was sintered by spark plasma sintering process. FE-SEM, HR-TEM and Raman analysis were carried out SKD11 carbon nanocomposites.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.2
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• pp.147-152
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• 2002

Carbon nitride thin films were deposited by reactive sputtering for the hard coating materials on Si wafer and tool steels. When the nitrogen content of carbon nitride film on tool steel is 33.4%, the mean hardness and elastic modulus are 49.34 GPa and 307.2 GPa respectively. The nitrided or carburised surface acts as the diffusion barrier which shows better adhesion of carbon nitride thin film on the steel surface. To prevent nitrogen diffusion from the film, steel substrate can be saturated by nitrogen forming a Fe$_3$N layer. The desirable structure at the surface after carburising is martensite, but sometimes, due to high carbon content an proeutectoid Fe$_3$C structure may form at the grain boundaries, leaving the overall surface brittle and may cause defects.

• Corrosion Science and Technology
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• v.11 no.5
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• pp.165-172
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• 2012

The corrosion resistance of epoxy-coated carbon steel was evaluated. The carbon steel surface was subjected to different treatment methods such as steel grit blasting with different size, steel shot ball blasting and power tool treatment. To study the effect of the treatments, the topology of the treated surface was observed by optical 3D microscopy and a pull-off adhesion test was conducted. The corrosion resistance of the epoxy-coated carbon steel was further examined by electrochemical impedance spectroscopy (EIS) combined with hygrothermal cyclic testing. The results of EIS indicated that the epoxy-coated carbon steel treated with steel grit blasting showed an improved corrosion resistance compared to untreated epoxy-coated surfaces or surfaces subjected to shot ball blasting and power tool treatments.

• Tribology and Lubricants
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• v.35 no.2
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• pp.139-147
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• 2019

This study investigates the effects of corrosion resistance characteristics of opponent materials in relative motion on the sliding wear behavior of mild carbon steel. Pin specimens made of mild carbon steel are tested at several sliding speeds against mating discs made of two types of alloyed steels, such as type D2 tool steel (STD11) and type 420 stainless steel (STS420J2), with different corrosion resistance characteristics in a pin-on-disc type sliding wear test machine. The results clearly show that the sliding wear behavior of mild carbon steel is influenced by the corrosion resistance characteristics of the mating disc materials at low sliding speeds. However, the sliding wear behavior at high sliding speeds is irrelevant to the characteristics because of the rising temperature. During the steady state wear period, the sliding wear rate of mild carbon steel against the type 420 stainless steel at a sliding speed of 0.5 m/s increases considerably unlike against the type D2 tool steel. This may be because the better corrosion resistance characteristics achieve a worse tribochemical reactivity. However, during the running-in wear period at low sliding speeds, the wear behavior of mild carbon steel is influenced by the microstructure after heat treatment of the mating disc materials rather than by their corrosion resistance characteristics.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.143-148
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• 1996

In this paper, we have studied internal quality including chemical compositions, microscopic structure and nonmetalic inclusion of test materials. We have analyzed dynamic characteristics of cutting force of milling including tensile strength value hardness etcs. Test materials are used the tempered carbon steel and the non-tempered carbon steel. The obtained results are as follows: 1.In analyzing internal quality, the tempered carbon steel have typical martensite structure and the non-tempered carbon steel have ferrite+pearlite structure. 2.Yield strength, tensile strength and hardness value are in the non-tempered carbon steel but elongation is maximum value in the tempered carbon steel. 3.Cutting force is smaller non-tempered carbon steel than tempered carbon steel when feed speed and depth of cut is constant. 4.Cutting force is smaller to the tempered carbon steel and smaller non-tempered carbon steel than tempered carbon steel when cutting conditions

• Corrosion Science and Technology
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• v.13 no.5
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• pp.163-169
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• 2014

The corrosion resistance of epoxy-coated carbon steel was evaluated. The carbon steel surface was subjected to different treatment methods such as steel grit blasting and power tool treatment as well as contamination of water soluble salt. To study the effect of the surface treatments and contamination, the topology of the treated surface was observed by confocal microscopy and a pull-off adhesion test was conducted. The corrosion resistance of the epoxy-coated carbon steel was further examined by electrochemical impedance spectroscopy (EIS) combined with immersion test of 3.5 wt% of NaCl solution. Consequently, the surface contamination by sodium chloride with $16mg/m^2$, $48mg/m^2$ and $96mg/m^2$ didn't affect the adhesion strength for current epoxy coated carbon steel and blister and rust were not observed on the surface of epoxy coating contaminated by various concentration of sodium chloride after 20 weeks of immersion in 3.5 wt% NaCl aqueous solutions. In addition, the results of EIS test showed that the epoxy-coated carbon steel treated with steel grit blasting and power tool showed similar corrosion protection performance and surface cleanness such as Sa 3 and Sa 2.5 didn't affect the corrosion protectiveness of epoxy coated carbon steel.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.4
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• pp.30-37
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• 1997

This thesis is concerned with the study on the characteristics of the tool failure occuring at the beginning of cutting in finish machining of hardened steels such as carbon tool steel and alloy tool steel by a ceramic tool (Al$_{2}$O$_{3}$+TiC) with nose radius. In the machining of hardened carbon steel STC3, the wear mechanism on the flank face of the ceramic tool is abrasion wear. The mode of tool failure is developed into catastropic fracture with flaking. It is thought that the fracture caused by FeO and TiO$_{2}$ results from the oxidation of Fe in the workpice and TiC in the ceramic tool and the deposit of Fe formed on the surface of the ceramic tool. In the machining of hardened alloy steel STD11, the wear mechanism on the flank face of the ceramic tool is that abrasion and adhesion wear exist simultaneously. The mode of tool failure at the beginning of cutting features is DOC notch wear. It is thought that the DOC notch wear caused by FeO and TiO$_{2}$results from the oxidation of Fe and TiC in the workpiece and ceramic tool, respectively.

• Design & Manufacturing
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• v.6 no.2
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• pp.90-95
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• 2012

The sheet metal forming proceccing is very important and indispensable in the automotive industry because the accuracy of prsee worked parts is directly related to the automotive quality. But when making mold it is difficult and expensive to modify mold. mold design technology is a critical technology in press plastic working. When design the mold there are lots of variables in press plastic working according to worked material, mold materials, conditions of heat treatment, clearance and so on. Abrasion of mold depends on these kind of conditions and sheared surface which is crucial for quality of product also depends on them. In this study, we conduct research on abrasion loss of mold according to 8, 10 and 12% of clearance for thickness of 1.0mm of worked material out of mold design variables of the products whose worked materials are high carbon steel and carbon tool steel by a practical experiment and perform a comparative evaluation of difference of abrasion loss mold with the alloy tool steel (STD11) and Tungsten Carbide (WC).