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CW Nd:YAG 레이저를 이용한 SM45C강의 표면경화특성
김지환,유영태,신호준,노경보 조선대학교 에너지.자원신기술연구소 2003 에너지·자원신기술연구소 논문지 Vol.25 No.1
Laser surface hardening is an effective technique used to improve the tribological properties and also to increase the service life of automobile components such as camshafts, crankshatfs, lorry brake drums and gears. High power CO_(2) lasers and Nd:YAG lasers are employed for localized hardening of materials and hence are of potential application in the automobile industries. The heat is conducted rapidly into the bulk of the specimen causing self-quenching to occur and the formation of martensitic structure. In this investigation, the microstructure features occurring in Nd:YAG laser hardening SM45C steel are discussed with the use of optical microscopic and scanning electron microscopic analysis. Moreover, This paper describes the optimism of the processing parameters for maximum hardened depth of SM45C steel specimens of 4.5㎜, 10㎜ thickness by using CW Nd:YAG laser. Travel speed was varied from 0.6m/min to 1.5m/min. The maximum hardness and case depth of SM54C steel are 76Hv and 0.688㎜ by laser hardening. When the surface of specimens was melted during laser hardening, the surface hardness of SM45C steel was decreased.
SM45C 와 STD_(11)의 CW Nd:YAG 레이저 표면경화 특성비교
김지환,유영태,신호준,오용석 조선대학교 에너지.자원신기술연구소 2003 에너지·자원신기술연구소 논문지 Vol.25 No.1
Laser surface hardening is an effective technique used to improve the tribological properties and also to increase the service life of automobile components such as camshafts, crankshatfs, lorry brake drums and gears. High power CO_(2) lasers and Nd:YAG lasers are employed for localized hardening of materials and hence are of potential application in the automobile industries. The heat is conducted rapidly into the bulk of the specimen causing self-quenching to occur and the formation of martensitic structure In this investigation, the microstructrual features occurring in Nd:YAG laser hardening SM45C and STD_(11) steel are discussed with the use of optical microscopic and scanning electron microscopic analysis. Moreover, This paper describes the optimisation of the processing parameters for maximum hardened depth of SM54C and STD_(11) steel specimens of 4.5㎜, 10㎜ thickness by using CW Nd:YAG laser.
오병덕,이용복,Oh, Byung-Duck,Lee, Yong-Bok 대한용접접합학회 2008 대한용접·접합학회지 Vol.26 No.3
SM45C steel rods being used generally for power transmission shafts and machine components was selected and welded by Butt-GMAW(Gas Metal Arc Welding) method. An estimation of fatigue life was studied by constructing S-N curve. Fatigue strength of base metal zone showed higher values than one of weld zone in low cycles between $10^4$ and $10^6$cycles. However, significant decrease in fatigue strength of base metal was found around $10^6$cycles, which were almost same as one of heat affected zone. This decrease was attributed that initial residual stress of the steel rods distributed by drawing process was diminished by continually applied load, and resulted in softening of base metal. The fatigue limit of the weld zone was highest in the boundary between deposited metal zone and heat affected zone, and followed by in the order of deposited metal zone, base metal zone, and heat affected zone. Based on these results, it is revealed that the stress for safety design of machine components using SM45C butt-welded steel rods must be selected within the region of the lowest fatigue limit of heat affected zone.
자동차부품용 SM45C강의 상자소둔 열처리 최적화 연구
박근웅(Keun Woong Park),문만빈(Man Been Moon),오현운(Hyun Woon Oh) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
Annealing softens steel hardened from cold working by the tandem mill and reversing mill. Many steelmakers using annealing process for machinability of cold steel sheet. In this study, batch type annealing is widely used to produce steel sheets like automobile cold rolled steel sheets and sheets used for the manufacture of automotive parts. We developed a BAF simulator to estimate the effects of BAF conditions on the mechanical properties of SM45C sheet for safety belt buckle . Conditions for the batch annealing process consist of various annealing time and temperature. SM45C sheets require a yield strength (30∼36㎏/㎟), tensile strength (43∼51㎏/㎟) and elongation (32∼37%). The optimum conditions of SM45C sheet for safety belt buckle are 20hr of soaking time and 710℃ of heating temperature at △T 30℃.
박진영 忠州大學校 2012 한국교통대학교 논문집 Vol.47 No.-
The effects of annealing temperature on the Charpy impact toughness of SM45C steel have investigated. The hardness of specimen decreased with increasing annealing temperature, similarly the ductility and the toughness increased with annealing temperature. The impact toughness of SM45C steel is increased that annealing treatment was done from 770 to 860 , while the toughness is inferior that the annealing temperature is rapidly decreased at 830 to 860 . In case the annealing temperature is 830 , the impact energy enables grain size of pearlite to be refined, and grain size of ferrite became relatively smaller and evenly distributed. The pearlite grain size is gradually increased with increasing annealing temperature from 740 to 860 . However, the grain coarsening proceeded rapidly with increasing annealing temperature above 730 . The dimples and cleavage fracture were observed on fracture surface.
AIP법에서 증착시간이 SM45C 강의 TiN 코팅층 성질에 미치는 영향
김해지(Hae-Ji Kim) 한국기계가공학회 2011 한국기계가공학회지 Vol.10 No.5
The effect of deposition time in arc ion plating on surface properties of the TiN-coated SM45C steel is presented in this paper. The surface roughness, micro-particle, micro-hardness, coated thickness, atomic distribution of TiN, and adhesion strength are measured for various deposition times. It has been shown that the deposition time has a considerable effect on the micro-hardness, the coated thickness, and the atomic distribution of TiN of the SM45C steels but that it has little influence on the surface roughness and adhesion strength.
AIP 법에서 증착시간이 SM45C 강의 TiN 코팅층 성질에 미치는 영향
김해지(Hae-Ji Kim),김남경(Nam-Kyung Kim),김광영(Kwang-Young Kim) 한국기계가공학회 2007 한국기계가공학회 춘추계학술대회 논문집 Vol.2007 No.-
The effect of deposition time in arc ion plating on surface properties of the TiN-coated SM45C steel is presented in this paper. The surface roughness, micro-particle, micro-hardness, coated thickness, atomic distribution of TiN, and adhesion strength are measured for various deposition times. It has been shown that the deposition time has a considerable effect on the micro-hardness, the coated thickness, and an atomic distribution of TiN of the SM45C steels but that it has little influence on the surface roughness and adhesion strength.
SM45C강의 연속파 Nd: YAG레이저표면경화와 고주파표면경화특성 비교
신호준(H. J. Shin),유영태(Y. T. Yoo),안동규(D. G. Ahn),신병헌(B. H. Shin) 한국정밀공학회 2005 한국정밀공학회 학술발표대회 논문집 Vol.2005 No.10월
Laser heat treatment technology is used for improving the feature of fatigue resistance and wear resistance in mobile parts. The purpose of this study is to compare the characteristics of laser heat treatment and high frequency heat treatment, which is commonly used in industrial place. For the preemptive experiment, the distribution, depth and size of hardening and its micro-structural features were compared between surface heat treatment case by defocusing and variables of each process for heat treatment by exclusively manufactured heat treatment optical system. As a result, high frequency heat treatment has wide distribution of hardening depth and width about 3 times larger than laser heat treatment, however, its average hardness showed 621.4Hv which is smaller than the average hardness of laser heat treatment with 691Hv.
박진영 한국교통대학교 2014 한국교통대학교 논문집 Vol.49 No.-
In this study, the effects of annealing temperature on the charpy impact toughness of SM45C steel has been investigated. With the result of the annealing treatment in wide ranges of temperatures, the specimen is changed into coarse ferrite and micro-perlite. There is a huge difference in the Hv of the specimen in the temperatures for annealing treatment. The experiment showed that there was a nonuniform degree of hardness in the temperature range of 790℃∼910℃. As the temperature for the annealing treatment increases, there is a tendency that impact energy is increased. At 820℃, it showed notably high level of energy. The reason for this seems to be because of the influences of the size of the crystal particle of austenite in high temperature. The fracture surfaces of the specimen appear to be a combination of characteristics of brittle fracture and ductile fracture in U-notch and V-notch specimens, also shear lips and river patterns are observed.