In this paper, we investigated the change of sectional shape according to the tension when the reed wire was rolled. When rolling is performed, the tension acting on the reed wire acts in the opposite direction of the rolling progress and prevents twisting or bending phenomenon. The shape of the cross section was changed according to the tension acting on the reed wire, and the reed wire was rolled by continuously rolling the flat rolled wire and the tension was applied to the reed wire to control the simulation. As a result of the experiment, it was confirmed that the dimensions of the thickness and width after rolling can be adjusted through the tension acting on the lead wire. It was also confirmed that as the tension increased, the length of the lead wire increased and the residual stress increased.

This paper deals with the dynamical analysis of a vessel that leads to capsize in regular beam seas. The complete investigation of nonlinear behaviors includes sub-harmonic motion, bifurcation, and chaos under variations of control parameters. The vessel rolling motions can exhibit various undesirable nonlinear phenomena. We have employed a linear-plus-cubic type damping term (LPCD) in a nonlinear rolling equation. Using the fourth order Runge-Kutta algorithm with the phase portraits, various dynamical behaviors (limit cycles, bifurcations, and chaos) are presented in beam seas. On increasing the value of control parameter Ω, chaotic behavior interspersed with intermittent periodic windows are clearly observed in the numerical simulations. The chaotic region is widely spread according to system parameter Ω in the range of 0.1 to 0.9. When the value of the control parameter is increased beyond the chaotic region, periodic solutions are dominant in the range of frequency ratio Ω=1.01~1.6. In addition, one more important feature is that different types of stable harmonic motions such as periodicity of 2T, 3T, 4T and 5T exist in the range of Ω=0.34~0.83.

Effects of annealing temperature on the microstructure and mechanical properties through thickness of a Cu-3.0Ni- 0.7Si alloy processed by differential speed rolling are investigated in detail. The copper alloy with a thickness of 3 mm is rolled to a 50 % reduction at ambient temperature without lubricant and subsequently annealed for 0.5 h at 200-900 oC. The microstructure of the copper alloy after annealing is different in the thickness direction depending on the amount of the shear and compressive strain introduced by the rolling; the recrystallization occurs first in the upper roll side and center regions which are largely shear-deformed. The complete recrystallization occurs at an annealing temperature of 800 oC. The grain size after the complete recrystallization is finer than that of the conventional rolling. The hardness distribution of the specimens annealed at 500-700 oC is not uniform in the thickness direction due to partial recrystallization. This ununiformity of hardness corresponds well to the amount of shear strain in the thickness direction. The average hardness and ultimate tensile strength has the maximum values of 250 Hv and 450 Mpa, respectively, in the specimen annealed at 400 oC. It is considered that the complex mode of strain introduced by rolling directly affects the microstructure and the mechanical properties of the annealed specimens.

Effects of annealing temperature on the microstructure and mechanical properties through thickness of a cold-rolled Cu-3.0Ni-0.7Si alloy were investigated in detail. The copper alloy with thickness of 3 mm was rolled to 50 % reduction at ambient temperature without lubricant and subsequently annealed for 0.5h at 200~900 oC. The microstructure of the copper alloy after annealing was different in thickness direction depending on an amount of the shear and compressive strain introduced by rolling; the recrystallization occurred first in surface regions shear-deformed largely. The hardness distribution of the specimens annealed at 500~700 oC was not uniform in thickness direction due to partial recrystallization. This ununiformity of hardness corresponded well with an amount of shear strain in thickness direction. The average hardness and ultimate tensile strength showed the maximum values of 250Hv and 450MPa in specimen annealed at 400 oC, respectively. It is considered that the complex mode of strain introduced by rolling effected directly on the microstructure and the mechanical properties of the annealed specimens.

본 연구는 어선전복경보시스템 개발을 위해 어선의 횡동요 특성을 파악하고 시간영역 횡동요 운동 시뮬레이션을 수행한다. 어 선전복경보시스템의 검증을 위해서는 전복 상황을 가정하여 시험을 수행하고 실제 어선 계측을 수행해야 하지만, 상황의 위험성으로 인 해 현실적으로 불가능하다. 또한 많은 전복사고의 경우 횡동요와 밀접한 연관이 있는 것으로 조사되었다. 이에 따라 어선전복경보시스템 의 핵심인 어선의 횡동요특성을 정확히 파악하여 시간영역 기반 횡동요 시뮬레이션을 수행하고 해당 정보를 통해 시스템에 탑재된 경보 시스템의 알고리즘을 검증한다. 주요내용으로 첫째, 횡동요 운동 특성을 운동 시험을 통해 계측하고 파악한다. 특히 어선과 같은 소형선 박의 경우 CFD 및 포텐셜 코드를 포함한 해석적인 방법으로 점성과 관련된 횡동요 해석이 어렵다. 이에 따라 횡동요 운동 모드에 초점을 맞추어 운동 시험을 수행하고 횡동요 RAO를 도출한다. 둘째, 횡동요 RAO를 이용하여 Wave Spectrum과의 조합으로 시간영역 운동 시뮬레 이션을 수행하고 전복 경보 알고리즘을 검증한다.

In the present study the microstructure of low-carbon steels fabricated by controlled rolling and accelerated cooling processes was characterized and identified based on various microstructure analysis methods including optical and scanning electron microscopy, and electron backscatter diffraction(EBSD). Although low-carbon steels are usually composed of α-ferrite and cementite(Fe3C) phases, they can have complex microstructures consisting of ferrites with different size, morphology, and dislocation density, and secondary phases dependent on rolling and accelerated cooling conditions. The microstructure of lowcarbon steels investigated in this study was basically classified into polygonal ferrite, acicular ferrite, granular bainite, and bainitic ferrite based on the inverse pole figure, image quality, grain boundary, kernel average misorientation(KAM), and grain orientation spread(GOS) maps, obtained from EBSD analysis. From these results, it can be said that the EBSD analysis provides a valuable tool to identify and quantify the complex microstructure of low-carbon steels fabricated by controlled rolling and accelerated cooling processes.

Fe-6.5 wt.% Si alloys are widely known to have excellent soft magnetic properties such as high magnetic flux density, low coercivity, and low core loss at high frequency. In this work, disc-shaped preforms are prepared by spark plasma sintering at 1223 K after inert gas atomization of Fe-6.5 wt.% Si powders. Fe-6.5 wt.% Si sheets are rolled by a powder hot-rolling process without cracking, and their microstructure and soft magnetic properties are investigated. The microstructure and magnetic properties (saturation magnetization and core loss) of the hot-rolled Fe-6.5 wt.% Si sheets are examined by scanning electron microscopy, electron backscatter diffraction, vibration sample magnetometry, and AC B–H analysis. The Fe-6.5 wt.% Si sheet rolled at a total reduction ratio of 80% exhibits good soft magnetic properties such as a saturation magnetization of 1.74 T and core loss (W5/1000) of 30.7 W/kg. This result is caused by an increase in the electrical resistivity resulting from an increased particle boundary density and the oxide layers between the primary particle boundaries.

Rolling contact fatigue(RCF) is a major cause of failure that appears in components of rolling contacts. In the recent years, the fatigue propagation and failure have been an important issue in respect of the safe operation and to reduce the noise and vibration of the rolling contact components. The water-contaminated lubrication is known to be one of the significant factors that reduces the lifetime of the rolling contact components. Thus, in this study, the effect of water-contaminated lubrication environment on the rolling contact fatigue was investigated. Bearing life testing was performed in two different lubrication conditions (i.e. normal lubrication environment and water-contaminated lubrication environment). The effect of the debirs on the rolling contact fatigue could be eliminated by establishing the debris filter system. Microscopic features of the rolling contact surfaces were examined using energy dispersive spectrometry and non-contact 3D measurement system. In the case of the water-contaminated lubrication, the increase of surface roughness values up to 17.6% was observed. The oxidation state and pattern of the rolling contact surfaces were very different depending on the lubrication environment. It was also found that the bearing rating life,   , was decreased significantly in the watercontaminated lubrication condition. The amount of reduction was about 49.7%.

A fatigue analysis considering dynamic effects yields a more accurate fatigue life prediction than static fatigue analysis because it considers effects of inertia, flexibility and resonance that occur in the structure up to its natural frequency. However, the dynamic fatigue analysis of bogie frames of the rolling stock is not yet taken into account in the norm EN 13749. Therefore, in order to assure the safety of the rolling stocks, it is important to examine the fatigue analysis of that considering dynamic effects under applied load histories. Moreover, since the bogie frame consists of various welded joints, it is necessary to evaluate fatigue life of that considering welding properties as well as dynamic effects. In this study, under load histories converted from measured acceleration histories, static and dynamic fatigue analysis of the welded bogie frame are performed respectively.

In this study, design and manufacturing automation systems for the rolling stone rolling stone production were as follows. Manufacturing of rolling stone was designed to obtain a desired rolling round for about 5-15° by the tilted the tilted the slope of the road rolling barrel. This stone can be manufactured by the conflicting with each other inside the barrel. Additionally, the stone cutting device was made to cut the stone having the standard sizes of this rolling stone about 100x100x100 mm for height, width, depth, respectively. Rolling stone was transferred to a cutting device using a conveyor belt, while a rubber on the conveyor belt was used to prevent the slip between the stone and this conveyor belt. The production of this rolling stone device was measured by a counter system, which was installed at the end of the conveyor belt bottom of the outlet.

The cold rolling workability and mechanical properties of two new alloys, designed and cast Al-5.5Mg-2.9Si and Al-7Mg-0.9Zn alloys, were investigated in detail. The two alloy sheets of 4 mm thickness, 30 mm width and 100 mm length were reduced to a thickness of 1 mm by multi-pass rolling at ambient temperature. The rolling workability was better for the Al-7Mg-0.9Zn alloy than for the Al-5.5Mg-2.9Si alloy; in case of the former alloy, edge cracks began to occur at 50% rolling reduction, and their number and length increased with rolling reduction; however, in the latter alloy, the sheets did not have any cracks even at higher rolling reduction. The mechanical properties of tensile strength and elongation were also better in the Al-7Mg-0.9Zn alloy than in Al-5.5Mg-2.9Si alloy. Work hardening ability after cold rolling was also higher in the Al-7Mg- 0.9Zn alloy than in the Al-5.5Mg-2.9Si alloy. At the same time, the texture development was very similar for both alloys; typical rolling texture developed in both alloys. These differences in the two alloys can primarily be explained by the existence of precipitates of Mg2Si. It is concluded that the Al-7Mg-0.9Zn alloy is better than the Al-5.5Mg-2.9Si alloy in terms of mechanical properties.

석재 굴림석을 보도 및 건축석으로 사용하기 위해 석재 굴림통 시스템을 제작하였다. 이 시스템을 사용하여 굴림석을 제작한 다음 굴림석에 대하여 기계적 성질을 측정한 결과 다음과 같은 결론을 얻었다. 석재 굴림통 시스템의 대한 출구부와 입구부에 대하여 굴림통 출구부 보다 입구부에서 진동이 높게 측정되었다. 포천석으로 만들어진 석재 굴림석에 대하여 압축강도, 흡수율, 비중을 측정한 결과 122MPa, 0.2%, 2.64g/m3을 얻었다. 포천석 석재 굴림석에 대하여 치수 정확도를 측정한 결과 표준편차가 0.02 이하로 측정되었다. 포천석 석재 굴림석에 대하여 굴림도를 측정한 결과 92.5% 이상의 R15 값이 측정 되어 측정되었다.

Wire rods having various sectional shape are generally used in various applications. In a 2-roll shape rolling process, step-by-step rolling operations are executed repeatedly and the rollers must be changed whenever the sectional shape of wire rod is changed. The frequent changes of the rollers and discontinuous repeated operations are cause various shortcomings such as increase of manufacturing cost and reduction in precision. We had developed a high precision automatic wire rod manufacturing system to reduce these shortcomings in the previous study. In this study, we evaluated the field application performance of the developed system in terms of straightness, thickness deviation, surface precision, tensile and hardness of the wire rod in order to verify the feasibility of the system.

Conflicting accounts of environmentally-friendly motives exist (see Chan, 2001; Hartmann & Apaolaza-Ibanez, 2012; Haws et al., 2014; Johnstone & Tan, 2015; Rashid, 2009; Royne et al., 2013). Recent research has turned to identity-society explanations (see Park & Lee, 2016). This research furthers this inquiry and narrows the gap. To understand environmentally-friendly clothing options (EFCO) motives better, this study uses uniqueness theory, which posits that consumers adopt dress different from mass fashion simply because it is unpopular (Snyder & Fromkin, 1977; Tian et al., 2001). Accordingly, environmentally-friendly attitudes should have nothing to do with the environment, but with norms, conformity, pressure (Law et al., 2004), and uniqueness. Thus, the research questions consist of: 1) is need for uniqueness in dress related to EFCO purchase intentions? 2) If so, does uniqueness relate to other EFCO motives? A survey was administered (n=220), using existing scales, to an online consumer panel All scales exhibited sufficient reliability. Pearson-Product Moment Scores and ANOVAs were used to assess variable relationships. As predicted, concern for the environment and perceived individual impact on the environment were unrelated to need for uniqueness. There was a significant and positive relationship between need for uniqueness and each of: attitudes toward EFCO and social pressure to act green. This indicates that individuals feel social pressure from important others to adapt to consumer trends. However, the manner in which they adopt mass consumer movements, such as sustainability, may be in more unique ways and via unpopular choice, such as EFCO. Finally, an ANOVA indicated that those high in uniqueness were willing to pay substantially more for EFCO.

Wire rods having various sectional shape are generally used directly in various applications. In the shape rolling, a couple of grooved rollers are used and the groove match the sectional shape of the wire rod. In this 2 roll system, a couple of rollers must be changed whenever the sectional shape of the wire rod is changed, and the frequent changes of roller cause rise of manufacturing cost. In this study, in order to apply a highly precise 4 roll rolling mill developed in previous studies on the shape rolling manufacturing process, the raw wire feeding equipment, 2 roll rolling mill, turks Head rolling mill, large heat treatment equipment, a steam cleaning equipment, a large winding equipment, cooling equipment, a tension adjustment equipment, designed and manufactured to the main control system. In addition, the problems corrected throughout these various equipments for manufacturing high-precision automatic rolling mill system developed by assembling more than six months and was conducted between complementary and testing process.

Wire rods having various sectional shape are generally used directly in various applications. In the shape rolling, a couple of grooved rollers are used and the groove match the sectional shape of the wire rod. In this 2 roll system, a couple of rollers must be changed whenever the sectional shape of the wire rod is changed, and the frequent changes of roller cause rise of manufacturing cost. We developed a 4 roll wire rolling mill that reduce the disadvantage of 2 roll rolling, at the same time improving quality of the wire rods and reducing production costs. The present work is focused on the development of a high precision 4 roll wire rolling mill for the wire rods that have various rectangle sectional shape.

Effects of conventional rolling(CR) and differential speed rolling(DSR) on the microstructure and mechanical properties of Cu-Ni-Si alloy were investigated in detail. The copper alloy with thickness of 3 mm was rolled to 50 % reduction at ambient temperature without lubricant with a differential speed ratio of 2:1. The conventional rolling in which the rolling speed of upper and lower rolls is identical was performed under identical rolling conditions. The shear strain introduced by the CR showed positive values at positions of upper roll side and negative values at positions of lower roll side. However, it showed zero or positive values at all positions for the samples rolled by the DSR. The microstrucure and texture development of the as-rolled copper alloy did not show any significant difference between CR and DSR. The tensile strength of the DSR processed specimen was larger than that of the CR processed specimen. The effects of rolling methods on the microstructure and mechanical properties of the as-rolled copper alloy are discussed in terms of the shear strain.

Hot rolling of Mg-6Zn-0.6Zr-0.4Ag-0.2Ca-(0, 8 wt%)Li powder was conducted at the temperature of 300 oC by putting the powder into the Cu pipe. The microstructure and mechanical properties of the samples were observed. Mg-6Zn- 0.6Zr-0.4Ag-0.2Ca without Li element was consisted of α phase and precipitates. The microstructure of the 8 wt%Li containing alloy consisted of two phases (α-Mg phase and β-Li phase). In addition, Mg2Zn3Li was formed in 8%Li added Mg-6Zn-0.6Zr- 0.4Ag-0.2Ca alloy. By addition of the Li element, the non-basal planes were expanded to the rolling direction, which was different from the based Mg alloy without Li. The tensile strength was gradually decreased from 357.1 MPa to 264 MPa with increasing Li addition from 0% to 8%Li. However, the elongation of the alloys was remarkably increased from 10 % to 21% by addition of the Li element to 8%. It is clearly considered that the non-basal texture and β phase contribute to the increase of elongation and formability.

A powder-in-sheath rolling (PSR) process utilizing a copper alloy tube was applied to a fabrication of a multi-walled carbon nanotube (CNT) reinforced aluminum matrix composite. A copper tube with an outer diameter of 30 mm and a wall thickness of 2 mm was used as a sheath material. A mixture of pure aluminum powders and CNTs with the volume contents of 1, 3, 5 vol% was filled in the tube by tap filling and then processed to 93.3% height reduction by a rolling mill. The relative density of the CNT/Al composite fabricated by the PSR decreased slightly with increasing of CNTs content, but showed high value more than 98%. The average hardness of the 5%CNT/Al composite increased more than 3 times, compared to that of unreinforced pure Al powder compaction. The hardness of the CNT/Al composites was some higher than that of the composites fabricated by PSR using SUS304 tube. Therefore, it is concluded that the type of tube affects largely on the mechanical properties of the CNT/Al composites in the PSR process.

The purpose of this paper is to examine the roll damping characteristics by bilge keels on the fishing vessel. Unlike other degree of freedom motions, roll motion is highly nonlinear. However the quantitative evaluation of roll damping combined with waves is very important for the fishing vessel. To reduce roll motion, roll motion stabilizers such as a bilge keel is used due to easy made and cheap cost rather than anti-rolling tank and fin-stabilizer. Authors paid attention to the shape of bilge keel and waves to grasp the roll damping for the fishing vessel and studied about the difference of tendencies of roll angle following the shapes of bilge keel. The model ship was the offshore large purse seiner and four types of bilge keel were used. The data from the experiments were provided and analyzed to investigate the rolling characteristics of the model ship being affected by the wave height, wave period and bilge keel shape. The results of the study showed that three types of the bilge keel have little effective, but only one has an effect on the roll damping. So bilge keel shape and its attachment method need to be a future study for the practical use in fishing vessel.