• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2006년 추계학술발표대회 개요집
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• pp.120-122
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• 2006

This study deals with characterizations of microstructure and wear performance of a cladding layer, product on 1.9 mm-thick mild steel plate by the electric resistance welding, of composite metal powder of Coarse WC-6.5%Co and high carbon alloy(SHA). The cladding layer was examined and tested fur microstructural features, chemical composition, hardness, wear performance and wear mechanism. The cladding layer have two different matrix were observed by an optical microscope and EPMA. The one was the coarse WC-6.5Co structure. The other was the melted SHA with surrounding the WC-6.5Co structure. The hardness of WC-6.5Co was 1210HV. The hardness of SHA was 640HV. In comparison by wear rate, the cladding layer showed the remarkable wear performance that was 15 times of SM490 and about 62% of D2.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.421-426
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• 2005

In general, structural integrity of rolling stock structures should last more than 25 years. During the lifetime corrosive degradation occurs. For structural design and diagnosis, quantitative relationship between corrosive degradation and variation of mechanical properties such as tensile strength and fatigue strength is needed. In this study, first of all we established the atmospheric corrosion test procedure. At regular intervals using specimens of SM490A and SS400 on the atmospheric corrosion test bed, we carried out tensile and fatigue tests. The fatigue strength decreases as the atmospheric corrosion period increases. And we studied the effect of post-weld heat treatment on the tensile and fatigue behaviour.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.775-779
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• 2007

The structural strength assessment of a carbody was performed using F.E. analysis and static test to verify the structural safety of newly manufactured carbody of a freight car. The freight car for the transportation of cold-rolled coils in steel making company was designed with SS400 steel for underframe and SM490A steel for bracket. Prior to the evaluation of structural strength, commercial finite element method(FEM) software was used for the stress and structural analyses on stress distribution in a carbody of freight car. The strain gages were attached on the carbody based on the FEM results. The actual vertical loading test and horizontal compression loading test were conducted, and the stress and displacement were obtained. Finally, the structural strength of carbody was evaluated by using a engineering techniques.

• 한국세라믹학회지
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• 제37권2호
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• pp.158-163
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• 2000

Six different SiC ceramics with SiO2-Re2O3 (Re=Yb, Er, Y, Dy, Gd, Sm) as sintering additives have been fabricated by hot-pressing the SiC-Re2Si2O7 compositions at 1850$^{\circ}C$ for 2 hr under a pressure of 25 MPa. The room temperature strneth and the fracture toughness of the hot-pressed ceramics were characterized and compared with those of the ceramics sintered with YAG (Y3Al5O12). Five SiC ceramics (Re=Yb, Er, Y, Dy, Gd) investigated herein showed sintered densities higher than 94% of theoretical. Tthe SiC-Re2Si2O7 compositions showed lower strength and comparable toughness to those from SiC-YAG composition, owing to the chemical reaction between SiO2 and SiC during sintering. SiC ceramics fabricated from a SiC-Y2Si2O7 composition showed the best mechanical properties of 490 MPa and 4.8 MPa$.$m1/2 among the compositions investigated herein.

• 동력기계공학회지
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• 제9권4호
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• pp.102-109
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• 2005

An attachment part of the construction equipment frequently claimed from the crack occurrence that takes especially at the bucket. therefore we execute the fatigue examination and changes the welding method at the same materials. we executed a fatigue crack propagation experiment and got the conclusions at the normal temperature and Frequency 10Hz. We carried out butt welding for structure steel of SM490A and make three kinds of specimen of different weld method each. The fatigue limit of CASE 1 was determined to the low than CASE 2, CASE 3. the CASE 2 putting the interval of the 2mm creates back plate and make fatigue limit to high. Bead shapes and weld surfaces shape influence on fatigue life of materials. Specially, the crack growth becomes starting point that gap of back-plate and boundary surface of bead. It is confirmed by fracture showing on this study.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1024-1028
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• 2006

The Fe-Mn damping Alloys which combine a high damping capacity with good mechanical properties can provide attractive technical and economic solutions to problems involving fatigue, noise and vibration. This study is aimed at finding its applicability to divided spherical bearing in bridge. The results obtained are summarized as follows : 1) The specific damping capacity of the Fe-Mn damping alloy is superior to that of SM490B. 2) The divided spherical bearing manufactured Fe-Mn damping alloy passes the load test to confirm applicability of that in bridge.

• Journal of Welding and Joining
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• 제25권1호
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• pp.14-23
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• 2007

A lot of fatigue tests on a material, JIS SM490A, with yielding strength of about 350 MPa and tensile strength of about 520 MPa were carried out. Various butt-welded specimens such as reinforcement removed, as-welded and weld toe ground, several types of fillet-welded specimens and full-size box type components were used. After having obtained S-N curves for the above- mentioned specimens, fatigue strengths were compared to those of foreign design codes, AWS, BS 7608 and ENV. It was found the fatigue strengths at low cycles are not in a good agreement with the foreign codes, but the fatigue limits are in a good agreement.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.359-364
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• 2004

We investigated the effect of weld details on fatigue behavior of a material, JIS SM 490 A, with yielding strength of about 350 MPa and tensile strength of about 520 MPa. Tensile tests, instrumented indentation tests and fatigue tests were carried out on double V-grooved butt weld plates such as reinforcement removed, as-welded and weld toe ground. In addition plates with transverse fillet welded web, load carrying cruciform fillet welded plates, non-load-carrying cruciform fillet welded plates and longitudinal butt welded plates were tested. S-N curves for the above specimens were obtained and analyzed

• 한국강구조학회 논문집
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• 제29권3호
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• pp.217-228
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• 2017

본 연구에서는 고강도강재를 적용한 비대칭 하이브리드 합성보의 휨성능을 실물대 실험을 통하여 평가하였다. 합성보의 웨브와 상부플랜지에는 일반강재(SM400, SM490)를 적용하고 하부플랜지는 상부플랜지에 비해 상대적으로 크게 제작하여 비대칭 단면으로 적용한 후 일반강재(SM520) 및 고강도강재(SM570, HSA800)를 각각 적용하였다. 본 연구의 주요 목적은 비대칭 하이브리드 합성보의 휨성능 평가 및 설계지침의 개발이다. 실험결과 하부플랜지에 일반강재를 적용한 실험체의 경우 $Dp/Dt{\leq}0.15$를 만족시킬 시 우수한 휨강도와 연성능력을 발현하는 것을 확인하였다. 반면 하부플랜지에 고강도강재가 적용된 실험체의 경우 휨내력의 증가로 인한 슬래브의 수평전단력 증가가 예상치 못한 슬래브 종방향 전단파괴를 발생시켜 소성강도에 도달하지 못하였다. 따라서 고강도강재를 적용한 비대칭 하이브리드 합성보의 경우 설계단계에서 슬래브 수평전단강도 확보가 필수적이다.

• 한국약용작물학회지
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• 제12권6호
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• pp.490-493
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• 2004

한국에 분포하고 있는 할미꽃속 5종에 대한 핵형 분석을 수행하여 다음과 같은 결과를 얻었다. 체세포 중기 염색체 수는 모두 2n=2x=16, 기본 염색체 수는 x=8로 관찰되었다. 가는잎할미꽃 (P. cernua)의 염색체 조성은 5쌍의 중부 염색체 (1, 2, 3, 4, 5번), 1쌍의 차중부 염색체 (6번)와 2쌍의 차단부 염색체 (7, 8번)로 핵형은 K(2n) = 2x = 16 = 10m + 2sm + 4st로 나타났고, 염색체의 크기는 $4.62{\sim}8.25\;{\mu}m$였다. 분홍할미꽃 (P. davurica), 할미꽃 (P. koreana) 및 중국할미꽃 (P. chinensis) 염색체 조성은 5쌍의 중부 염색체 (1, 2, 3, 4, 5번)와 3쌍의 차단부 염색체 (6, 7, 8번)로 핵형은 K(2n) = 2x = 16 = 10m + 6st로 유사하게 나타났다. 염색체의 크기는 분홍할미꽃 에서 $5.90{\sim}10.66\;{\mu}m$, 할미꽃에서 $5.25{\sim}8.80\;{\mu}m$, 중국할미꽃에서 $4.33{\sim}6.99\;{\mu}m$로 차이를 보였다. 동강할미꽃 (P. tongkangenesis)의 염색체조성은 5쌍의 중부 염색체 (1, 2, 3, 4, 5번), 2쌍의 차중부 염색체 (6, 7번)와 1쌍의 차단부 염색체 (8번)로 핵형은 K(2n) = 2x = 16 = 10m + 4sm + 2st로 구분되었으며, 염색체의 크기는 $4.67{\sim}8.97\;{\mu}m$로 나타났다.