• Title/Summary/Keyword: strength, surface roughness

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Effect of Substrate Roughness on the Adhesion of TiN Deposition by PACVD (플라즈마 화학증착법에 있어 모재의 표면조도가 TiN 박막층의 밀착력에 미치는 영향에 관하여)

  • Kang, H.Y.;Kim, M.I.
    • Journal of the Korean Society for Heat Treatment
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    • v.4 no.2
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    • pp.27-37
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    • 1991
  • The adhesion strength of TiN films to substrate(STC 3) steel has been studied using the scratch adhesion test. Before deposition, the substrates were mechanically polished and TiN films were deposited at different substrate temperature($480^{\circ}C-540^{\circ}C$). The chemical properties of TiN films were investigated by RBS, and EDS, and the physical properties were investigated by micro-hardness tester, SEM, and X-ray diffractometer. According to results of this study, the adhesion strength of TiN films increase with increasing the deposition temperature. The roughness of the polished substrates surface were measured with a profilometer. It was observed that, as a general rule, the adhesion strength of deposited TiN films increase with decreasing the substrates surface roughness.

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The influence of the hollow and solid shaft cross sectionof SM 30 C steel on corrosion fatigue strength (SM 30 C강의 중공 중실축 단면변화 부식피로강도에 미치는 영향)

  • 신규동;장백선;김웅집
    • Journal of Ocean Engineering and Technology
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    • v.11 no.2
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    • pp.28-38
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    • 1997
  • The corrosion fatigue test was conducted in air to investigate the corrosion fatigue strength of SM 30 C steel by which was corroded in the under sea and surface in the conditions of 3.0% NaCl salt solution. The fatigue tests were carried out on a rotary bending testing machine of cantilever type. The corrosion effect of the sea surface conditionwas served more than that of the under sea condition which was due ti the periodic contact of air thus accelerate the corrosion. The difference of the fatgue strength between sea surface and under sea conditions decreased with increase of stree level and corroded period. Inthe case of the solid shaft and thickness 2mm of hollow shaft, the difference of corrosion fatigue strength decreased as stress level and corrosion periodic increasing. Onthe contrary in the case of thickness 1mm of hollow sgaft, the difference of it increased as stress level, corrosionn periooodic increasing and also the condition of corrosion chaanged. The main factors affecting the degradation of fatigue strength due to corrosion were the reduction of sectional area and the increase of surface roughness. The interference phenomenon increase with stress level got higher.

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EFFECTS Of VARIOUS SILANE COUPLING AGENTS ON THE STRENGTH AND THE SURFACE ROUGHNESS OF GLASS FIBER-ADDED PMMA RESIN (수종의 실란처리 유리섬유를 첨가한 의치상용 레진의 강도변화 및 마모전.후 표면성상분석)

  • Lee, Sang-Il;Kim, Chang-Whe;Lim, Young-Jun;Kim, Myung-Joo;Yun, Suk-Dae
    • The Journal of Korean Academy of Prosthodontics
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    • v.45 no.4
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    • pp.457-468
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    • 2007
  • Statements of problem: The fracture of acrylic resin dentures remains an unsolved problem. Therefore, many investigations have been performed and various approaches to strengthening acrylic resin, for example, the reinforcement of heat-cured acrylic resin using glass fibers, have been suggested over the years. Silane is important for bonding between glass fiber and resin. Purpose: The aim of the present study was to investigate the effect of various silane on the strength of PMMA resin and roughness of resin-glass fiber complex after abrasion test. Material and methods: 3mm glass fiber (Chopped strand, Hankuk fiber Co., Milyang, Korea) was treated with 3 kinds of silane (MPS, EPS, APS) (Sila-ace, Chisso chemical, Tokyo, Japan) and mixed with PMMA resin(Vertex RS, Vertex Dental B.V., Zeist, Netherlands). Transverse strength and Young's modulus was measured using Instron (Instron model 4466, Instron, Massachusetts, USA). After abrasion test (The 858 Mini Bionix II Test System, MTS System Co., Minnesota, USA) surface roughness was evaluated using tester (Form Talysurf plus, Taylor Hopson Ltd., Leicester England). Examination of scanning electron microscope was also performed. Results: Within this study, the following conclusions were drawn. 1. Surface treatment of glass fiber with MPS and APS increased transverse strength of PMMA resin complex, but surface treatment with EPS decreased transverse strength of PMMA resin complex (p<0.05). 2. Silane treated glass fiber increased Young's modulus of PMMA resin complex compared to desized glass fiber (p<0.05). 3. Roughness increased after abrasion test in case of PMMA resin reinforced with desized glass fiber (p<0.05). 4. Roughness change was not observed after abrasion test in case of PMMA resin reinforced with silane treated glass fiber (p>0.05).

The effect of ball diameter upon surface accuracy in surface rolling with cast iron (주철의 서어피스 로울링에 있어서 가압 볼의 직경이 표면정밀도에 미치는 영향)

  • 허명규;최홍식;육광수
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.12 no.5
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    • pp.1071-1082
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    • 1988
  • Surface rolling is one of the micro plastic processes which yields local deformation of surface, and improves surface roughness, hardness and fatigue strength. With the use of gray cast iron (GC 30) as material for experiment, the changes in surface roughness were investigated. A number of previous theses were refered to the effects of surface rolling for this study. With the use of steel ball of excellent in surface roughness and hardness, and with the applied force 20Kgf, surface rolling was performed. The summary of the experiment is as follows: (1) With the fixed applied force 20Kgf and the ball of 8.726mm in diameter, surface roughness was found to be the most excellent. (2) Increase in hardness was most prominent in the first rolling, but less effective in the succeeding rolling. (3) Reduction on diameter was affected by the previous process before rolling, and about 70 to 90% of reduction was made in the first rolling.

Surface Quality Improvements on the Spherical Shaped Mold using Ball End Milling (볼 엔드밀을 이용한 금형 구면 가공의 표면품질 향상에 관한 연구)

  • Yun, Il-Woo;Hwang, Jong-Dae
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.3
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    • pp.71-76
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    • 2020
  • Various machining methods are being studied to improve the processing quality of the spherical R shape in press die. In this paper, we confirmed that changes in machining quality were associated with changes in cutting direction, path, and cutting angle, which are commonly used in the machining of molds. We obtained a surface roughness graph with each condition change in one specimen using an instrument that measured geometry and surface roughness simultaneously. The results of the study showed that the best surface roughness in the finish cut of the spherical surface was obtained using upward pick feed machining.

The Effect of Surface Environment on the Mechanism in Oblique Cutting (3차원 절삭에서 표면환경이 절삭기구에 미치는 영향)

  • Seo, Nam-Seob
    • Journal of the Korean Society for Precision Engineering
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    • v.1 no.2
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    • pp.24-32
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    • 1984
  • The object of the study is to discuss the effect of magic ink as a surface active substance on the mechanism of chip formation in oblique cutting. The Rehbinder effect has been known as a phenomenon that the mechanical strength reduces when the metal is coated with some surface active substances. In order to interpret these surface effects defined by Rehbinder, the influence on the shear strength of shear plane by coating surface active substances, cutting force by the depth of cut, surface roughness and hardness ratio were observed. The results are as follows: 1. By coating the magic ink on free surface of the forming chip, the effective shear angle increases, and the cuttinbg force and the deformed chip thickness decreases. 2. With the large inclination angle the effective shear angle increases, and the specific cutting force and the friction angle decrease. 3. Cutting of the coated surface improves the surface roughness and the hardness ratio drops, which means another Rehbinder effect.

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An Experimental Study on Cutting Characteristic of Ceramics (세라믹스의 절삭거동에 관한 실험적 연구)

  • 이길우;김순태
    • Journal of the Korean Ceramic Society
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    • v.30 no.5
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    • pp.420-426
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    • 1993
  • The machinability of ceramics has been experimentally studied. The experiments were conducted on alumina cernmics of various purity, quartz, and cordierite using the sintered diamond tools and CBN tools. Tool wasre, surface roughness, and cutting resistence were measured and analysed. It was found that the workpieces could be machined with the diamond and CBN tools, but the sintered diamond tools were more efficient for the machining of the high strength ceramics. The machining of alumina ceramics with sintered diamond tools showed that (1) wet machining prolonged tool life comparing with dry machining, (2) workpiecewith higher purity had better surface roughness, (3) severe cutting conditions led to the chipping and fracture of tool and increase of the surface roughness and cutting resistance, (4) 20~40m/min of cutting speed, 0.01~0.02mm/rev of feed, and 0.1~0.2mm of cutting depth are suggested as proper cutting conditions for the high strength ceramics.

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Cutting Characteristics and Deformed Layer of Type 316LN Stainless Steel (Type 316LN 스테인리스강의 절삭특성과 가공 변질층)

  • Oh, Sun-Sae;Yi, Won
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.2
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    • pp.196-205
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    • 2004
  • The cutting characteristics and the deformed layer of nitrogen(N)-added type 316LN stainless steel were comparatively investigated to type 316L stainless steel. The cutting force, the surface roughness(Ra) and the tool wear in face milling works were measured with cutting conditions, and the deformed layers were obtained from micro-hardness testing method. The cutting resistance of type 316LN was similar to type 316L in spite of its high strength. The surface roughness of type 316LN was superior to type 316L for all the cutting conditions. In particular, in the high cutting speed above 345m/min, the surface roughness of the two stainless steels was closely same. The deformed layer thickness of the two stainless steels was generated in the 150$\mu\textrm{m}$-300$\mu\textrm{m}$ ranges, and its value of type 316LN was lower than that of type 316L. This is due to the high strength properties by nitrogen effect. It was found that type 316LN was higher in the tool wear than that type 316L, and flank wear was dominant to crater wear. In face milling works of type 316LN steel, tool wear is regarded as a important problem.

Investigation of shear behavior of soil-concrete interface

  • Haeri, Hadi;Sarfarazi, Vahab;Zhu, Zheming;Marji, Mohammad Fatehi;Masoumi, Alireza
    • Smart Structures and Systems
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    • v.23 no.1
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    • pp.81-90
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    • 2019
  • The shear behavior of soil-concrete interface is mainly affected by the surface roughness of the two contact surfaces. The present research emphasizes on investigating the effect of roughness of soil-concrete interface on the interface shear behavior in two-layered laboratory testing samples. In these specially prepared samples, clay silt layer with density of $2027kg/m^3$ was selected to be in contact a concrete layer for simplifying the laboratory testing. The particle size testing and direct shear tests are performed to determine the appropriate particles sizes and their shear strength properties such as cohesion and friction angle. Then, the surface undulations in form of teeth are provided on the surfaces of both concrete and soil layers in different testing carried out on these mixed specimens. The soil-concrete samples are prepared in form of cubes of 10*10*30 cm. in dimension. The undulations (inter-surface roughness) are provided in form of one tooth or two teeth having angles $15^{\circ}$ and $30^{\circ}$, respectively. Several direct shear tests were carried out under four different normal loads of 80, 150, 300 and 500 KPa with a constant displacement rate of 0.02 mm/min. These testing results show that the shear failure mechanism is affected by the tooth number, the roughness angle and the applied normal stress on the sample. The teeth are sheared from the base under low normal load while the oblique cracks may lead to a failure under a higher normal load. As the number of teeth increase the shear strength of the sample also increases. When the tooth roughness angle increases a wider portion of the tooth base will be failed which means the shear strength of the sample is increased.

Effects of Rod-roughened Wall on a Turbulent Boundary Layer (막대형 표면조도가 난류경계층에 미치는 영향)

  • Lee, Seung-Hyun;Kim, Jung-Hun;Doh, Deog-Hee;Sung, Hyung-Jin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.7
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    • pp.518-528
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    • 2008
  • The effects of surface roughness on a turbulent boundary layer (TBL) were investigated using particle image velocimetry (PIV). The roughness elements used were periodically arranged two-dimensional spanwise rods, and the roughness height was ${\kappa}/{\delta}$. Introduction of the roughness elements increased the wake strength and the turbulent stress not only in the roughness sublayer but also in the outer layer. This indicates the existence of interaction between inner and outer layers for 2D rod-roughened wall. Roughness effects on a turbulence structure near the wall were obtained by PIV measurements. Iso-contours of mean velocities and Reynolds stresses in the roughness sublayer showed a very good agreement with previous DNS results.