http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
고주파 담금질에 의한 SCM440강의 기계적 특성에 관한 연구
안석환(Seok-Hwan Ahn),남기우(Ki-Woo Nam),김태일(Tae-Il Kim),이문용(Mun-Yong Lee),김동규(Dong-Kyu Kim) 한국해양공학회 2009 韓國海洋工學會誌 Vol.23 No.2
Surface hardening treatment, such as using the high-frequency induction hardening method, are widely used to increase the fatigue life and prevent the failure of materials by locally increasing the surface hardness. This method, in particular, brings an improvement in static strength by compressive residual surface stress due to the hardening. In this study, the mechanical properties of high-frequency induction hardened SCM440 steel were investigated. These results were also compared with those for base metal and a Q/T (tempering after quenching) treatment specimen. The test results showed that partially high-frequency induction hardened SCM440 steel specimens were more improved in static strength, surface hardness, fatigue limit, and anti-wear than the base metal and Q/T treatment specimens. In particular, the fatigue limit of the hig-frequency induction hardened SCM440 steel increased by more than about 52% compared to that of base metal and by about 25% compared to that of the Q/T specimen.
CM440 강에 대한 트리에탄올아민의 부식억제에 관한 연구
박근호 한국유화학회 2015 한국응용과학기술학회지 Vol.32 No.1
일반적인 3-전극 시스템의 순환전압전류법을 사용하여 유기부식억제제인 트리에탄올아민 (TEA)을 첨가하여 SCM440 강에 대한 전류-전압 곡선을 측정하였다. 그 결과 SCM440 강의 C-V특성 은 순환전압전류법으로부터 산화전류에 기인한 비가역 공정으로 나타났다. 확산계수는 부식억제제 TEA 의 농도를 2.5 x 10-4 M에서 5,0 x 10-4 M로 2배로 증가시킴에 따라 확산계수는 각각 2.561 x 10-6 cm2s-1에서 1.707 x 10-6 cm2s-1로 1.5배로 감소하므로 부식억제효과가 좋음을 알 수 있었다. 그리고 전 해질 농도변화에 따르는 효과는 전해질 농도를 0.5 N에서 1.0 N로 증가시키면, 확산계수는 각각 5.12 x 10-6 cm2s-1에서 2.56 x 10-6 cm2s-1로 2배로 감소하므로 1.0 N의 전해질의 사용이 적합하였다. In this study, the current-voltage curves for the SCM440 steel by the addition of an organic corrosion inhibitor triethanolamine(TEA) was measured using the conventional three electrodes of cyclic voltammetry. As a result, the C-V characteristics of SCM440 steel were to be for an irreversible process due to the oxidation current from the cyclic voltammetry. Diffusion coefficient according to the twice increasing the concentration of TEA in the corrosion inhibitor from 2.5 x 10-4 M to 5.0 x 10-4 M, the diffusion coefficient was found to be a good corrosion-inhibiting effect is reduced by 1.5 times, so for each 2.561x 10-6 cm2s-1 to 1.707 x 10-6 cm2s-1. When according to the electrolyte concentration and the effect is to increase the electrolyte concentration to 1.0 N at 0.5 N, the diffusion coefficient is 2.56 x 10-6 cm2s-1 to 5.12 x 10-6 cm2s-1, each 2 times decrease in the use of the electrolyte of 1.0 N, because this was more appropriate.
플라즈마 이온질화 공정온도가 SCM440강의 내구성에 미치는 영향
정상옥(Sang-Ok Chong),박일초(Il-Cho Park),이천호(Cheon Ho Lee),김성종(Seong-Jong Kim) 대한용접·접합학회 2019 대한용접·접합학회지 Vol.37 No.5
In this study, plasma ion nitriding technology was applied to investigate the effect of plasma ion nitriding temperature and the surface roughness of SCM440 steel on the durability of SCM440 steel for gear material. The mechanical properties of the plasma ion nitrided specimens were examined using a comprehensive analysis of nitriding depth, phase change, microstructure and micro-Vickers hardness values. As a result, the durability of SCM440 steel was found to be more significantly affected by plasma ion nitriding temperature than surface roughness. As the plasma ion nitriding temperature increased, the composite phase of brittle γ"- Fe₄N + ε-Fe2-3N was converted into a single phase of γ"-Fe₄N, and the depth of the nitride layer increased, making it suitable for gear materials.
SCM415강의 정적 및 동적 변형거동에 미치는 탄화물 구상화율 변화에 관한 연구
김헌주 ( Heon Joo Kim ),임종민 ( Jong Min Lim ) 한국열처리공학회 2004 熱處理工學會誌 Vol.17 No.6
N/A Effect of spherodization of cementite on static and dynamic deformation behaviors of SCM415 steels was investigated in this study. Dynamic torsional test was conducted using torsional Kolsky bar with the strain rate of 1.6 x 10³/s. Three types of specimens were used with different spherodization degree of cementite. Dynamic test results were analyzed comparing with static tensile results and microstructural changes. The obtained results are as follows; 1) All the specimens of static and dynamic tests showed a ductile fracture mode of dimple. Specimens of the dynamic test showed adiabatic shear bands on the beneath of fracture surface. 2) In static tensile test, decreased tensile strength and increased uniform and non-uniform elongations appeared as spherodization degree of cementite increased. 3) In dynamic torsional test, decreased shear strength and increased uniform elongation appeared as spherodization degree of cementite increased. 4) Due to the largest uniform elongation, superior cold forgeability at high speed is expected on high spherodization degree of cementite.
백운봉(U. B. Baek),박종서(J. S. Park),박휘립(H. R. Park),김동진(D. J. Kim),최병호(B. H. Choi) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11
Gear is the one of most widely used device for transmitting power. In the design of gear ensuring reliability, bending strength of tooth root, pitting resistance of contact surface, and scoring strength are considered to determine transmitting power of gear. In 1892, W. Lewis designed tooth of gear by simplifying it as cantilever beam to calculate bending strength of gear tooth. But the bending strength is the fatigue phenomenon related to crack initiation in tooth root. This paper presents high cycle fatigue properties of carburized SCM420H steel which is widely used as the material for gear and failure analysis of gear are also performed.
이중 쇼트 피닝에 의한 SCM822H 강의 무해화 균열 크기 평가
최진우 ( Jin-woo Choi ),윤서현 ( Seo-hyun Yun ),권영국 ( Yung-kug Kwon ),이금화 ( Gum-hwa Lee ),남기우 ( Ki-woo Nam ) 한국산업융합학회 2023 한국산업융합학회 논문집 Vol.26 No.6
In this study, the harmless crack size (a<sub>hml</sub>) by double shot peening (DSP) using shot balls with different diameters was evaluated on carburized, quenched-tempered SCM822H steel. The minimum crack size (a<sub>NDI</sub>) detectable by non-destructive inspection was also evaluated. The relationship between the crack size (a<sub>25,50</sub>) that reduces the fatigue limit by 25% and 50% and a<sub>hml</sub> was evaluated. The residual stress of DSP was greater in SP(0.6+0.08) than SP(0.8+0.08) and appeared deeper in the depth direction. In addition, the hardness below the surface appeared larger. The fatigue limit of DSP increased 2.07 times and 1.95 times compared to non-SP. All a<sub>hml</sub> of the DSP specimen was determined at the depth (a). The compressive residual stress distribution affects a<sub>hml</sub>, and the a<sub>hml</sub> of SP(0.6+0.08), which has a large compressive residual stress and a high fatigue limit, appeared large. a<sub>hml</sub> of SP<sub>(0.6+0.08)</sub> introduced deeper than the residual stress of SP<sub>(0.8+0.08)</sub> is larger in the range of As=1.0-0.3. Since the residual stress in the thickness direction has a greater effect on a<sub>hml</sub> than the residual stress at the surface, it is necessary to introduce it more deeply. The relation of a<sub>hml</sub>, a<sub>25,50</sub>, and aNDI were evaluated in the point for safety and reliability.
기어 강도 향상을 위한 SCM420H재의 고농도 침탄 열처리에 관한 연구
김범중,최덕기 한국기계기술학회 2017 한국기계기술학회지 Vol.19 No.5
Recently, weight lightening is a key issue for various mechanical components to improve the fuel efficiency. For this reason, many researchers have been studying focused on the development of surface hardening treatment and metallic materials with high strength and wear resistance. In this study, we examine the formation of carbide at the surface of the gear machined by SCM420H steel after super- carburizing in order to improve the wear resistance of gear. The experimental results show that super- carburizing heat treatment gives rise to carbide dispersion across wider range of depth and higher carbon concentration than general carburizing heat treatment. Carbide having spheroidal or spherical shape had a size under 2 micro-meter produced in austenite grain boundaries or within austenite grains during super-carburizing. The super- carburized specimen maintained the hardness, HV700 above, at the 0.6mm depth and had a 10.4% lower coefficient of friction which was 0.766. This results from the dispersed carbide which lowered the coefficient of friction and ended up affecting wear resistance. Consequently, we conclude that super-carburizing heat treatment has more influence on the improvement of hardness, wear resistance compared to general carburizing heat treatment.
쇼트 볼의 크기에 따르는 SCM822H 강의 무해화 균열크기 평가
최진우,윤서현,남기우 한국산업융합학회 2023 한국산업융합학회 논문집 Vol.26 No.5
In this study, the harmless crack size was evaluated using carburized, quenched- tempered SCM822H steel. The possibility of detecting cracks that reduce the fatigue limit by non-destructive inspection was evaluated. The conclusions obtained are as follows. The retained austenite of surface was reduced by SP. About 35% and 65% of the retained austenite on the surface were transformed into strain-induced martensite, increasing the hardness by 79HV and 122HV over the as-received material. The maximum compressive residual stresses introduced on the surfaces were -695 MPa and -688 MPa, respectively. The fatigue limit increased by 1.48 times and 1.67 times, respectively, compared to the as-received material. The harmless crack size of SP specimen was determined differently depending on the shot ball size.