• 제목/요약/키워드: Tensile properties

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구상흑연주철 FCD60과 Cr-Mo강 SCM440 확산접합부의 인장성질에 미치는 접합조건의 영향 (The Effect of Bonding Condition on Tensile Properties of Diffusion Bonds of Graphite Cast Iron FCD60 to Cr-Mo Steel SCM440)

  • 송우현;김정길;강정윤
    • Journal of Welding and Joining
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    • 제22권1호
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    • pp.77-82
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    • 2004
  • The effect of bonding condition on tensile properties of joints diffusion bonded spheroidal graphite cast iron, FCD60 to Cr-Mo steel, SCM 440 was investigated. Diffusion bonding was performed with various temperatures, holding times, pressures and atmospheres. All tensile specimens were fractured at the bonding interface. The tensile strength and elongation was increased with increasing bonding temperature. Especially, tensile strength of joints bonded at 1123K was higher than that of a raw material, FCD60, and tensile strength of joints bonded at 1173K was equal to that of a raw material, SCM440, but elongation of all joints was lower than those of raw materials. There was little the effect of holding time on the tensile properties. In comparison with bonding atmosphere, the difference of tensile strength was not observed, but elongation of joint bonded at vacuum(6.7mPa and 67mPa) was higher than that of Ar gas. Higher the degee of vacuum, elongation increased. Tensile properties of diffusion bonds depended on microstructures of cast iron at the interface and void ratio. Microstructures of cast iron at interface changed with temperature, because decarburizing and interdiffusion at the interface occurs and transformation of austenite-1 ferrite + graphite occurs on the cooling process. The void ratio decreased with increasing temperature, especially, effected on the elongation.

Effect of Hydrogen Charging Time and Tensile Loading Speed on Tensile Properties of 304L Stainless Steels

  • Hwang, SeungKuk;Lee, Sangpill;Lee, Jinkyung;Bae, Dongsu;Lee, Moonhee;Nam, Seunghoon
    • 한국산업융합학회 논문집
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    • 제22권1호
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    • pp.11-20
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    • 2019
  • This study dealt with the tensile strength characteristics of stainless steel 304L steel by hydrogen charging. Especially, the effect of hydrogen charging time on the tensile strength and ductility of 304L stainless steels was evaluated, in conjunction with the observation of their fracture surfaces. The tensile properties of hydrogen-charged 304L stainless steels were also investigated with the variation of tensile loading speeds. The hydrogen amount of 304L stainless steels obviously increased with the increase of hydrogen charging time. The tensile properties of 304L stainless steels were clearly affected by the short term charging of hydrogen. In particular, the elongation of 304L stainless steels decreased with increasing hydrogen charging time, due to the hydrogen embrittlement. It was also found that the tensile properties of hydrogen-charged 304L stainless steels were very sensitive to the crosshead speed for tensile loading.

Poly(trimethylene terephthalate, PTT) 1×1리브 편성물의 신장특성에 관한 연구 (A Study of the Tensile Properties for Poly(trimethylene terephthalate, PTT) 1×1 Rib Knitted fabrics)

  • 최재우;장봉식
    • 한국산업융합학회 논문집
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    • 제9권4호
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    • pp.337-341
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    • 2006
  • The tensile properties of Poly(trimethylene terephthalate, PTT) $1{\times}1Rib$ knitted fabrics were experimentally studies, and the specimens has $1{\times}1$ rib stitched structure which are weft knitted fabrics with various lengths of loop. The $1{\times}1$ rib weft knitted fabric showed larger tensile linearity, tensile energy and tensile resilience in the direction of courses. The tensile properties increased with increasing the loop density in all directions, and perfectly increased with the course directions than the wale directions.

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Tensile Properties of Hybrid Fiber-Reinforced Reactive Powder Concrete After Exposure to Elevated Temperatures

  • Li, Haiyan;Liu, Gang
    • International Journal of Concrete Structures and Materials
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    • 제10권1호
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    • pp.29-37
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    • 2016
  • The paper presents a research project on the tensile properties of RPC mixed with both steel and polypropylene fibers after exposure to $20-900^{\circ}C$. The direct and the indirect tensile strength (in bending) were measured through tensile experiment on dog-bone specimens and bending experiment on $40{\times}40{\times}160mm$ prisms. RPC microstructure was analyzed using scanning electron microscope. The results indicate that, steel fibers can significantly improve the tensile performance of hybrid fiber-reinforced RPC, whereas polypropylene fibers have no obvious effect on the tensile performance. With increasing temperature, the flexural and axial tensile strength of hybrid fiber-reinforced RPC substantially decrease linearly, which attributes to the deteriorating microstructure. Based on the experimental results, equations are established to express the decay of the flexural and tensile strength with increasing temperature.

Green Composites. I. Physical Properties of Ramie Fibers for Environment-friendly Green Composites

  • Nam Sung-Hyun;Netravali Anil N.
    • Fibers and Polymers
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    • 제7권4호
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    • pp.372-379
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    • 2006
  • The surface topography, tensile properties, and thermal properties of ramie fibers were investigated as reinforcement for fully biodegradable and environmental-friendly 'green' composites. SEM micrographs of a longitudinal and cross sectional view of a single ramie fiber showed a fibrillar structure and rough surface with irregular cross-section, which is considered to provide good interfacial adhesion with polymer resin in composites. An average tensile strength, Young's modulus, and fracture strain of ramie fibers were measured to be 627 MPa, 31.8 GPa, and 2.7 %, respectively. The specific tensile properties of the ramie fiber calculated per unit density were found to be comparable to those of E-glass fibers. Ramie fibers exhibited good thermal stability after aging up to $160^{\circ}C$ with no decrease in tensile strength or Young's modulus. However, at temperatures higher than $160^{\circ}C$ the tensile strength decreased significantly and its fracture behavior was also affected. The moisture content of the ramie fiber was 9.9 %. These properties make ramie fibers suitable as reinforcement for 'green' composites. Also, the green composites can be fabricated at temperatures up to $160^{\circ}C$ without reducing the fiber properties.

고속압밀 열가소성수지 복합재료의 인장 특성 (Tensile Properties of Rapid Consolidated Thermoplastic Composites)

  • 김홍건;최창용;유기현;김성철;양성모;노홍길
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2002년도 추계학술대회 논문집
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    • pp.504-507
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    • 2002
  • Glass fiber reinforced PET (Poly-Ethylene-Terephthalate) matrix composite was manufactured by rapid press consolidation technique as functions of temperature, pressure and time in pre-heating, consolidation and solidification stages. The optimal manufacturing conditions for this composite were discussed based on the void content, tensile, interlaminar shear, and impact properties. A tensile test was attempted to investigate the mechanical properties of the composite. It is found that the level of crystallinity and microstructure affects on the tensile properties substantially.

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Estimation of tensile strength of ultramafic rocks using indirect approaches

  • Diamantis, Konstantinos
    • Geomechanics and Engineering
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    • 제17권3호
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    • pp.261-270
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    • 2019
  • Because the estimation of the tensile strength is very important in any geotechnical project, many attempts have been made to determine. But the immediate determination of the tensile strength is usually difficult owing to well-shaped specimens, time-consuming, expensive and sometimes unreliable. In this study, engineering properties of several ultramafic rock samples were measured to assess the correlations between the Brazilian Tensile Strength (BTS) and degree of serpentinization, physical, dynamic and mechanical characteristics. For this purpose, a comprehensive laboratory testing program was conducted after collecting thirty-two peridotite and fifty-one serpentinite rock samples, taken from central Greece, in accordance with ASTM and ISRM standards. In addition, a representative number of them were subjected to petrographic studies and the obtained results were statistically described and analysed. Simple and multiple regression analyses were used to investigate the relationships between the Brazilian Tensile Strength and the other measured properties. Thus, empirical equations were developed and they showed that all of the properties are well correlated with Brazilian Tensile Strength. The curves with the $45^{\circ}$ line (y = x) were extracted for evaluating the validity degree of concluded empirical equations which approved approximately close relationships between Brazilian Tensile Strength and the measured properties.

미량 Sn을 함유한 AZ91 마그네슘 합금의 미세조직 및 기계적 특성 (Microstructure and Mechanical Properties of AZ91 Magnesium Alloy Containing a Small Amount of Sn)

  • 전중환
    • 열처리공학회지
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    • 제27권3호
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    • pp.115-120
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    • 2014
  • Microstructural features were comparatively investigated in AZ91 (Mg-9%Al-1%Zn) and AZ91-0.5%Sn alloys, in order to clarify the reason for the enhancement in room temperature tensile properties by the addition of small amount of Sn in Mg-Al-based alloy. In as-cast state, the Sn-containing alloy showed increased YS, UTS and elongation than the Sn-free alloy. The microstructural examination revealed that various factors including finer cell size, reduction of lamellar (${\alpha}+{\beta}$) phase and morphological change of bulky ${\beta}$ phase from partially divorced shape to fully divorced shape, are likely to be responsible for the improvement in tensile properties for the Sn-containing alloy. It is noted that two alloys showed similar tensile properties after solution treatment. This implies that microstructural evolution related to the ${\beta}$ phase plays a key role in better tensile properties in the Sn-containing alloy.

Effect of molding condition on tensile properties of hemp fiber reinforced composite

  • Takemura, K.;Minekage, Y.
    • Advanced Composite Materials
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    • 제16권4호
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    • pp.385-394
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    • 2007
  • In this study, the effect of molding condition on the tensile properties for plain woven hemp fiber reinforced green composite was examined. The tensile properties of the composite were compared with those of the plain woven jute fiber composite fabricated by the same process. Emulsion type biodegradable resin or polypropylene sheet was used as matrix. The composites were processed by the compression molding where the molding temperature and its heating time were changed from 160 to $190^{\circ}C$ and from 15 to 25 min, respectively. The following results were obtained from the experiment. The tensile property of hemp fiber reinforced polypropylene is improved in comparison with polypropylene bulk. The strength of composite is about 2.6 times that of the resin bulk specimen. Hemp fiber is more effective than jute fiber as reinforcement for green composite from the viewpoint of strength. The molding temperature and time are suitable below $180^{\circ}C$ and 20 min for hemp fiber reinforced green composite. Hemp fiber green composite has a tendency to decrease its tensile strength when fiber content is over 50 wt%.

인장 물성 측정 불확도 평가 (Estimation of Measurement Uncertainty in Evaluation of Tensile Properties)

  • 허용학;이해무;김동진;박종서
    • 대한기계학회논문집A
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    • 제34권1호
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    • pp.73-78
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    • 2010
  • 재료의 인장 물성 측정 불확도 평가가 수행되었다. 인장 물성 측정에 영향을 주는 불확도의 요인이 구분되어 분석되었고 인장 시험으로부터 측정되는 측정량, 즉 탄성계수, 항복 강도 그리고 인장 강도의 불확도 평가 모델이 본 연구에서 제시되었고 각 측정량에 대한 대응하는 수학적 모델과 측정치로부터 각 측정치의 감도계수를 계산함으로서 유도 되었다. 각 모델에 근거하여 ISO 6892에 따라 결정되는 SUS316LN의 실험적 데이터로부터 인장 물성의 불확도가 평가되었다.