경량 피스톤 로드를 위한 마찰용접 적용연구(SM45C/SM45C-Pipe 사용)

민병훈,임형택,민택기,Min, Byung-Hoon,Lim, Hyung-Taek,Min, Taeg-Ki 대한용접접합학회 2008 대한용접·접합학회지 Vol.26 No.2

Various research to reduce weight of a car is achieving. This research is tendencious to manufacture solid piston rod of shock absorber as hollow piston rod using friction welding. This study deals with the friction welding of SM45C to SM45C-Pipe that is used in car shock absorber, The friction time was variable conditions under the conditions of spindle revolution of 2,000rpm, friction pressure of 55MPa, upset pressure of 75MPa, and upset time of 2.0seconds. Under these conditions, the microstructure of weld interface, tensile fracture surface and mechanical tests were studied of friction weld, and so the results were as follows. 1. In tensile strength, the hole processing is better than non-hole processing. 2. When the friction time was 1.5seconds under the conditions, the maximum tensile strength of the friction weld happened to be 869MPa, which is 103% of SM45C's tensile strength and 91% of SM45C's Pipe. 3. When the friction time was 2.0seconds under the conditions, the maximum bending strength of the friction weld happened to be 1599MPa, which is 80% of SM45C's bending strength and 118% of SM45C's Pipe.

SKH51/SM45C의 마찰용접특성에 관한 연구

이세경,민병훈,최수현,심도기,민택기,Lee, Se-Gyoung,Min, Byung-Hoon,Choi, Su-Hyun,Shim, Do-Ki,Min, Taeg-Ki 대한용접접합학회 2007 대한용접·접합학회지 Vol.25 No.6

The present study examined the mechanical properties of the friction welding of shaft made of SKH51 and SM45C, of which the diameter is 12mm. Friction welding was done at welding conditions of 2,000rpm, friction pressure of 104MPa, upset pressure of 134MPa, friction time of 0.5sec to 2.5sec by increasing 0.5sec, upset time of 2 seconds. Under these conditions, a tensile test, a bending test, a shear test, a hardness test and a microstructure of weld interface were studied. When the friction time was 1.0 second under the conditions, the maximum tensile strength of the friction weld observed to be 963MPa, which is 89% the tensile strength of SKH51 base metal and 101% of the tensile strength of SM45C base metal. When the friction time was 1.0 seconds under the conditions, the maximum bending strength of the friction weld happened to be 1,647MPa, which is 78% the bending strength of SKH51 base metal(2,113MPa) and 87% of the bending strength of SM45C base metal(1,889MPa). When the friction time was 1.0 seconds under conditions, the maximum shear strength of the friction weld was observed to be 755MPa, which is 92% the shear strength of SKH51 base metal and 122% of the shear strength of SM45C base metal. According to the hardness test, the hardness distribution of the weld interface varied from Hv282 to Hv327. HAZ was formed from the weld interface to 1.2mm of SKH51 and 1.6mm of SM45C. Upon examination it was found that the microstructure became finer along with increase of friction revolution radius.

SM45C 강의 narrow gap 용접부 회전굽힘 피로 특성

한승전 ( Seung Zeon Han ),안지혁 ( Jee Hyuk Ahn ),이재현 ( Je Hyun Lee ),김상식 ( Sang Shik Kim ) 대한금속재료학회(구 대한금속학회) 2014 대한금속·재료학회지 Vol.52 No.11

SM45C steel was welded by conventional CO2 arc and narrow gap welding (NGW). The fatigue strength of NGWed sample had a value about 90 MPa higher than that of the CO2 arc welded sample. The width of welding and heat affected zone in NGWed samples decreased about 40% compared to the conventional CO2 arc welded sample. The hardness value of the welding zone in the NGW sample was 33.3% higher than that of the CO2 arc welded sample. The microstructure change of the SM45C during NGW revealed that the matrix was transformed to the martensite phase. With the small width of welding and heat affected zone in the NGW, therefore, the specimen with NGW had a faster cooling rate after welding. We therefore concluded that the hardness was increased by hard martensite formation during cooling after NGW, and this increase in hardness resulted in better fatigue strength of SM45C steel compared to conventional CO2 arc welding. (Received March 13, 2014)

SM45C의 레이저 표면경화특성

신호준,유영태,안동규,임기건 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

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 CO₂ 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 3mm thickness by using CW Nd:YAG laser. Travel speed was varied from 0.6m/min to 1.0m/min. The maximum hardness and case depth fo SM45C steel are 780Hv and 0.4mm by laser hardening.

SM45C재의 UNSM 처리에 의한 트라이볼러지 특성 변화

심현보,서창민,서민수,AMANOVAUEZHAN,편영식 한국해양공학회 2018 韓國海洋工學會誌 Vol.32 No.6

The following results were obtained from a series of studies to accumulate data to reduce the coefficient of friction for press dies by performing tribological tests before and after the UNSM treatment of SM45C. The UNSM-treated material had a nano-size surface texture, high surface hardness, and large and deep compressive residual stress formation. Even when the load was doubled, the small amount of abrasion, small weight of the abrasion, and width and depth of the abrasion did not increase as much as those for untreated materials. When loads of 5 N, 7.5 N, and 10 N were applied to the untreated material of SM45C, the coefficient of friction was approximately 0.76–0.78. With the large specimen, a value of 0.72–0.78 was maintained at a load of 50 N despite the differences in the size of the wear specimen and working load. Tribological tests of large specimens of SM45C treated with UNSM under tribological conditions of 100 N and 50 N showed that the frictional coefficient and time constant stably converged between 0.7 and 0.8. The friction coefficients of the small specimens treated with UNSM showed values between 0.78 and 0.75 under 5 N, 7.5 N, and 10 N. The friction coefficients of the SM45C treated with UNSM were comparable to each other.

SM45C재의 PVD코팅과 필름에 의한 트라이볼러지 특성

심현보,서창민,김종형,서민수 한국해양공학회 2018 韓國海洋工學會誌 Vol.32 No.6

In order to accumulate data to lower the friction coefficient of a press mold, tribological tests were performed before and after coating SM45C with a PVC/PO film and plasma coating (CrN, concept). The ultrasonic nanocrystal surface modification (UNSM)-treated material had a nano-size surface texture, high surface hardness, and large and deep compressive residual stress formation. Even when the load was doubled, the small amount of abrasion, small weight of the abrasion, and width and depth of the abrasion did not increase as much as those of untreated materials. A comparison of the weight change before and after the tribological test with the CrN and the concept coating material and that of the untreated material showed that the wear loss of the concept coating material and P-UNSM treated material (that is, the UNSM treated material treated with the concept coating) showed a tendency to decrease by approximately 55–75%. Concept 100N had a lower friction coefficient of about 0.6, and P-UNSM-30-100N showed almost the same curve as concept 100N and had a low coefficient of friction of about 0.6. The concept multilayer coating had a thickness of 5.32 μm. In the beginning, the coefficient of friction decreased because of the plasma coating, but it started to increase from about 250–300 s. After about 350 s, the coefficient of friction tended to approach the friction coefficient of the SM45C base metal. The SGV-280F film-attached test specimen was slightly pushed back and forth, but the SM45C base material was not exposed due to abrasion. The friction coefficient was 0.22, which was the lowest, and the tribological property was the best in this study.

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.

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.

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.

경량화 쇽업소바 피스톤로드에 사용되는 SM45C/SM20C-Pipe의 마찰용접에 관한 연구

민병훈(Byung-Hoon Min),최수현(Su-Hyun Choi),강정식(Jeong-Sik Kang),이형호(Hyung-Ho Lee),민택기(Taeg-Ki Min) 한국생산제조학회 2008 한국생산제조학회지 Vol.17 No.4

Various researches to reduce weight of a vehicle are achieving. One of these researches is tendencious to manufacture the hollow piston rod using friction welding instead of solid one of the vehicle shock absorber. This study deals with the friction welding of SM45C to SM20C-pipe that is used normally in the vehicle shock absorber. The friction time was variable conditions under the conditions of spindle revolution of 2,000rpm, friction pressure of 55㎫, upset pressure of 75㎫, and upset time of 2.0seconds. Under these conditions, the microstructure of weld interface, tensile fracture surface and mechanical tests of friction weld were studied and so the results were as follows. When the friction time was l.5seconds under the conditions, the maximum tensile strength of the friction weld happened to be 837㎫, which is 113% of SM20C's tensile strength and 97% of SM45C's. The optimal welding conditions were n=2,000rpm, P₁=55㎫, P₂=75㎫, t₂=1.5sec, t₂=2.0sec when the total upset length is 1.7㎜.