• Title/Summary/Keyword: High temperature tensile properties

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Effect of Deformation Temperature and Manganese Contents on the Tensile Properties of Fe-Cr-Ni-Mn Duplex Stainless Steel (Fe-Cr-Ni-Mn 2 상 스테인레스강의 인장성질에 미치는 변형온도 및 Mn 함량변화의 영향)

  • Kang, C.Y.;Sung, J.H.
    • Journal of the Korean Society for Heat Treatment
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    • v.4 no.4
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    • pp.44-52
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    • 1991
  • The effect of deformation temperature and manganes contents on the tensile properties of duplex stainless steels with the structure of both ferrite and austenite were investigate. For this investigation, Fe-19% Cr-5% Ni-4~8% Mn alloys were prepared. The result obtained from this experiment are summerized as follows. With decreasing deformation temperature, tensile strengths of duplex stainless steel increased. Elongation showd to be increased and then decreased after representing the highest value at specific temperature. Tensile properties of duplex stainless steel were controlled by TRIP behavior in this experimental range of austenite contents. Tensile strengths decreased with increasing Mn contents. With increasing Mn contents, elongation decreased in the high temperature region, but increased in the low temperature region. The peak temperature representing the maximum elongation were changed to low temperature and the width of peak appeared to be broaden with increasing Mn contents.

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A Study on the Microstructures and High Temperature Tensile Properties of Ni-base Superalloy Melt-Spun Ribbons (Ni 기 초합금 급냉응고 리본의 미세구조와 고온 인장특성에 관한 연구)

  • Han, Chang-Suk
    • Journal of the Korean Society for Heat Treatment
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    • v.27 no.4
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    • pp.180-184
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    • 2014
  • In order to make clear relationship between high temperature tensile properties and fine microstructure of rapidly solidified cast-type Ni-base superalloys without heat treatment required for consolidation process, tensile test was carried out by changing strain rate from $5{\times}10^{-5}s^{-1}$ to $2{\times}10^{-2}s^{-1}$ and test temperature from $900^{\circ}C$ to $1050^{\circ}C$ using IN738LC and Rene'80 melt-spinning ribbons by twin roll process which were superior to ribbons by single roll process from the viewpoint of structure homogeneity. The dependence of tensile strength on strain rate and test temperature was studied and strain rate sensitivity, m, were estimated from tensile test results. From this study, it was found that tensile strength was influenced by ${\gamma}^{\prime}$ particle diameter, test temperature and strain rate, and m of ribbons exhibited above 0.3 over $950^{\circ}C$.

Application of Advanced Indentation System for Evaluati Tensile Property Degradation of Cr-Mo Steel (Cr-Mo 강의 열화도 평가를 위한 Advanced Indentation System의 응용)

  • Jang, Jae-Il;Choi, Yoel;Lee, Yun-Hee;Kwon, Dong-Il;Kim, Jeoung-Tae
    • Proceedings of the KSME Conference
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    • 2001.06a
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    • pp.231-236
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    • 2001
  • A newly developed Advanced Indentation System (AIS), which is a portable and nondestructive system for evaluating tensile properties, was used to measure mechanical behavior of materials used under high temperature and pressure conditions. This test measures indentation load-depth curve during indentation and analyzes the mechanical properties related to deformation and fracture. Aging effects of Cr-Mo and Cr-Mo-V steel at high temperature were simulated. Tensile properties including yield strength and tensile strength at various temperature are obtained from the test. For all test materials and conditions, the AIS-derived results were in good agreement with those from conventional standard test method. Examples of the test results ate given and potential applications of the AIS to assess the integrity of aging structures are briefly discussed.

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Effect of Deformation Temperature, Strain Rate and Grain Size on the Tensile Properties of 304L Stainless Steel (304L stainless Steel의 인장성질에 대한 변형온도, 변형속도 및 결정입도의 영향)

  • Kang, C.Y.;Sung, J.H.
    • Journal of the Korean Society for Heat Treatment
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    • v.3 no.2
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    • pp.20-31
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    • 1990
  • This investigation has been carried out to make clear the effect of deformation temperature, strain rate and grain size on the tensile properties of 304L stainless steel. Tensile properties of the metastable austenitic 304L steel remarkably influenced by deformation temperature. Tensile strength increased with decreasing deformation temperature and the elongation showed maximum value near $40^{\circ}C$. In order to obtain the high elongation, a large amount of deformation is available in austenite before martensitic transformation and the martensite has to be induced gradually. Tensile strength and elongation increased with decreasing grain size. The temperature representing the maximum elongation shifted to low temperature and the peak width of elongation became broaden with decreasing austenite grain size. The volume fraction of strain induced martensite decreased with decreasing austenite grain size. As the strain rate increase, the temperature representing the maximum elongation value shifted to high temperature and volume fraction of strain induced martensite decreased.

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Creep & Tensile Properties of Thermally Grown Alumina Films (열 생성 알루미나 박막의 크리프 및 인장 특성)

  • Ko, Gyoung-Dek;Sun, Shin-Kyu;Kang, Ki-Ju
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.6 s.261
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    • pp.665-670
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    • 2007
  • Alpha-phase alumina TGO(Thermally Grown Oxide) forms on the interface between zirconia top coat and bond coat of thermal barrier coating system for superalloys during exposure to high temperature over $1000^{\circ}C$. It is known to provide a good protection against hot corrosion and to cause surface failure such as rumpling and cracking due to difference in thermal expansion coefficient from the substrate metal and the lateral growth. Consequently, mechanical properties of the alumina TGO at the high temperature are the key parameters determining the integrity of TBC system. In this work, by using Fecralloy foils as the alumina forming substrate, creep tests and tensile tests have been performed with various TGO thicknesses$(h=0{\sim}4{\mu}m)$ and yttrium contents(0, 200ppm) at $1200^{\circ}C$. Displacement-time curves and load-displacement curves for each TGO thickness(h=1,2,..) were measured from the creep and tensile tests, respectively, and compared with the curves without TGO thickness(h=0). As the result, the intrinsic tensile and creep properties of TGO itself were determined.

The Effect of Thermal Exposure on the Microstructural Evolution and Tensile Properties in Cast Hastelloy X (Hastelloy X 주조재의 열간 노출에 따른 미세조직 및 인장 특성 변화)

  • Choi, Baig Gyu;Kim, In Soo;Do, Jeonghyeon;Jung, Joong Eun;Jung, In Yong;Hong, Hyun Uk;Jo, Chang Yong
    • Journal of Korea Foundry Society
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    • v.37 no.5
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    • pp.139-147
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    • 2017
  • Microstructural evolution of cast Hastelloy X during thermal exposure has been investigated. OM, SEM, and TEM microscopy were carried out on the as-cast, the standard heat treated, and the thermally exposed conditions. Tensile tests were also conducted to understand the effect of microstructural evolution on the degradation of tensile properties. Coarse $M_6C$ and fine $M_{23}C_6$ carbides were found in as-cast Hastelloy X with fine carbides on sub-boundary. Some of $M_{23}C_6$ carbide dissolved into the matrix during solution heat treatment and dislocation network formed at the interface between the carbide and the matrix due to the misfit strain. There was no significant microstructural difference between the exposed specimens at $400^{\circ}C$ and the solution heat treated specimen. A large amount of $M_{23}C_6$ carbides precipitated along and near grain boundaries and sub-boundaries after exposure at $650^{\circ}C$. Exposure at $870^{\circ}C$ of the alloy caused precipitation of $M_6C$ and ${\mu}$. The strength increased and the elongation decreased by thermal exposure at $650^{\circ}C$ and $870^{\circ}C$ because carbides interfere with the movement of the dislocation. It was found that the precipitation of carbide gave significant effects on the tensile properties of Hastelloy X.

Characterization of High Temperature Mechanical Properties of Cast Stainless Steels for Exhaust Manifold (배기다기관용 주강소재의 고온특성 평가)

  • Lee, Kyu-Dong;Ha, Tae-Kwon;Jung, Jae-Young
    • Transactions of Materials Processing
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    • v.18 no.3
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    • pp.217-222
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    • 2009
  • Automobile industries have been focusing their efforts on the development of exhaust manifolds using high temperature stainless steels. Exhaust manifolds fabricated with stainless steels can be categorized into tubular and cast ones. The former is usually manufactured by forming and welding process and the latter by vacuum casting process. In the present study, high temperature mechanical properties of 5 austenitic and 4 ferritic stainless steels were investigated by performing a series of high temperature tensile and low cycle fatigue tests. One of the austenitic stainless steels was vacuum cast and the others sand cast. Fatigue life of ferritic stainless steels was higher than that of austenitic ones.

HIGH TEMPERATURE DEFORMATION BEHAVIOR OF AUSTENITIC STAINLESS STEELS FOR EXHAUST MANIFOLD (Exhaust Manifold 용 오스테나이트계 스테인리스 강의 고온 변형특성)

  • Lee, K.D.;Ha, T.K.;Jeong, H.T.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.10a
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    • pp.314-317
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    • 2007
  • Domestic automobile industries have been focusing their effort on development of exhaust manifolds using high temperature stainless steel. Exhaust manifolds fabricated with stainless steels can be categorized into tubular and cast ones. The former is usually manufactured by forming and welding process and the latter by vacuum casting process. In the present study, high temperature mechanical properties of 5 austenitic stainless steels, one was sand cast and the others vacuum cast, were investigated by performing a series of high temperature tensile tests and high temperature low cycle fatigue tests.

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Tensile characteristics of Alumina Thin Film at High Temperature (고온에서 알루미나 박막의 인장특성)

  • 선신규;강기주
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.1344-1347
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    • 2004
  • Recently, Study on measuring property of a micro thin film(nm ~ hundreds of ) under Thermal Mechanical loading. In this work, We perform tensile test at high temperature(1200 ) to investigate mechanical properties of alumina TGO formed under Thermal Barrier Coating. We used Digital Image Correlation method for measuring displacement, and We presented a method of tensile test for thin film at high temperature.

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The Characteristics of Electrical Breakdown and Tensile Stress of Dielectric Paper for Insulation of HTS Cable (고온 초전도 케이블 절연을 위한 절연지의 인장응력 및 절연파괴 특성)

  • Kim, Young-Seok;Kwak, Dong-Soon;Kim, Hae-Jong;Kim, Sang-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.05a
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    • pp.61-64
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    • 2003
  • The degradation of the dielectric properties of insulating papers that were used under loaded conditions at cryogenic temperature was paid attention. Electrical and tensile stress properties of dielectric paper at cryogenic temperature have been investigated to optimum insulating design of high-Tc superconducting(HTS) cable. Tensile strength of PPLP in liquid nitrogen was high more than that of air, but tensile strain could know that decrease sharply. According as tensile strength increases, the breakdown stress of PPLP in liquid nitrogen was decreased.

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