合金工具鋼의 磨耗特性에 關한 硏究

金石三 경북대학교 공과대학 1982 工大硏究誌 Vol.11 No.-

Friction and wear tests of dry sliding were performed on alloyed tool steel (STS 3) to investigate tribometric characteristics and surface characteristics. The results obtained are as follows: 1) The coefficient of friction decreases with the normal load and nearly independent on sliding velocity (μ=0.3 - 0.7) 2) The average hardness of wear surface increases with the normal pressure, but it stays constant above the normal pressure of 0.45 ㎏/㎟ 3) In a given wear regime, the abraded wear volume of STS3 increases linearly with normal load.

合金工具鋼(STD11)의 摩擦面加工層의 性質

金載昊,金石三 경북대학교 공과대학 1981 工大硏究誌 Vol.10 No.-

The frictional experiments have been carried out on alloyed tool steel (STD11) to investigate frictional surface and its hard layer. The results obtainedare as follows; The average hardness of frictional surface increases with the compressing force, but decreases after a specific compressing force. It also increases with the sliding distance, but stays constant after a specific sliding distance. The thickness of hard layer due to friction increases with the sliding distance.

合金工具鋼의 와이어 컷 放電 加工面에 대한 트라이볼로지적 特性

변운봉,김석삼 경북대학교 산업기술연구소 1994 産業技術硏究誌 Vol.22 No.-

In this paper was examined the tribological characteristics of the worn surface of alloy tool steel STD11, machined by Wire-cut to choose the best work condition. In heat treating the specimens, after quenching in a vacuum furnace, each specimens were treated low tempering and high tempering. Then the 1st cut and 2nd cut were made with different conditions. After that the friction and wear test, for the microscophic observation of worn surface, by using SEM carried out to investigate wear process. The result obtained through this study are summarized as follows. The friction coefficient of the 2nd cut surface was greater than that of the 1st cut surface obtained by Wire-cut E D M. The wear rate of cut surface was higher than that of 1st cut surface obtained by Wire-cut E D M. The wear rate of the Wire-cut E D M surface after high tempering was lower than that surface after low tempering. The Wire-cut E D M surface has a wear mechanism that induces brittle fracture when a crack is generated and grown up to a critical length due to stress concentrations around craters.

무기질필러의 형상이 복합 레진의 마모에 미치는 영향

서세광,김교한,김석삼 대한치과기재학회 2000 대한치과재료학회지 Vol.27 No.4

The purpose of this study was to understand the effect of filler morphology on the wear characteristics of commercial composite resins containing 4 different types of filler, such as prepolymerized particle fillers, irregular-shaped fillers, prepolymerized particle fillers with irregular-shaped fillers, and round-shaped fillers, respectively. The wear test was conducted using a ball-on flat test machine. The results obtained were as follows; 1.The friction coefficient of the composite resins containing prepolymerized particle fillers was lower than those of the other 3 types of composite resins. 2.The wear characteristics, including the wear volume, specific wear rate, and width and depth of the wear track exhibited a similar tendency relative to the magnitude of the friction coefficient. However, the Palfique Toughwell containing a submicron spherical filler, which showed a similar friction coefficient to the other composite resins, revealed the lowest wear resistance of the composite resins examined. 3.Based on a SEM observation of the worn surfaces, the composite resins containing a prepolymerized particle filler exhibited smooth worn surfaces, The composite resins containing either an irregular-shaped filler or an irregular-shaped filler with prepolymerized particle filler showed similar worn surfaces. Among the composite resins containing only a round-shaped filler, Z100 exhibited a rough surface with the extrusion of the round filler, whereas Palfkque Toughwell showed a smooth worn surface.

치과용 콤퍼머의 마찰·마멸거동

임정일,강만석,김교한,김석삼 대한치과기재학회 1999 대한치과재료학회지 Vol.26 No.4

The friction and wear characteristics and wear mechanisms of dental compomers were investigated. Compomers such as Compoglass, F2000, Elan and Dyract AP were selected as specimens. Surface characteristics was examined by SEM and contents of glass fillers in specimens were determinated in order to analyze the effect of the fillers in fraction and wear characteristics. Ball on flat wear tester was used for a wear test. Friction and wear tests are carried out at room temperature. The friction coefficient of F2000 was quite high relatively, and the wear resistance of Compoglass and Dyract AP was better than that of F2000 and other specimens at the same experimental condition. The main wear mechanism is brittle fatigue of glass fillers, plastic flow and abrasive wear by crack propagation.

Engineering Education System of Malaysia

Seock-Sam Kim 한국트라이볼로지학회 2014 한국트라이볼로지학회 학술대회 Vol.2014 No.10

Tribological Characteristics of Magnetron Sputtered MoS₂ films in Various Atmospheric Conditions

Seock-Sam Kim,Chan-Wook Ahn,Tae-Hyung Kim 대한기계학회 2002 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.16 No.9

The friction and wear behaviors of magnetron sputtered MoS₂ films were investigated through the use of a pin and disk type tester. The experiments were performed for two kinds of specimens (ground (Ra 0.5㎛) and polished (Ra 0.01 ㎛) substrates) under the following operating condifions : linear sliding velocities in the range of 22 ~ 66 mm/s(3 types), normal loads varying from 9.8 ~ 29.4 N (3 types) and atmospheric conditions of air, medium and high vacuum (3 types). Silicon nitride pin was used as the lower specimen and magnetron sputtered M0S₂ on bearing steel disk was used as the upper specimen. The results showed that low friction property of the M0S₂ films could be identified in high vacuum and the specific wear rate in air was much higher than that in medium and high vacuum due to severe oxidation. It was found that the main wear mechanism in air was oxidation whereas in high vacuum accumulation of plastic flow and adhesion, were the main causes of wear.<br/>

Propagation Analysis of Surface Crack Due to Hertzian Contact

Kim, Seock-Sam Korean Tribology Society 1992 한국윤활학회지(윤활학회지) Vol.17 No.4

취성재료의 마멸천이기구를 규명하기 위해 반무한탄성체상에 표면균열이 존재할 때 그 위를 헤르쯔 접촉하중이 이동할 경우를 해석모델로 하여 선형파괴역할을 도입하여 해석하였다. 해석방법으로는 표면균열을 인상전위의 연속분포로 치환하여 Erdogan-Gupta의 방법으로 균열끝면의 응력확대계수를 구하여, 취성재료의 균열전파조건인 Erdogan-Sih Criterion을 사용하여 그 전파특성을 해석하였다. 본 논문에서는 마멸율이 적은 마멸에서 마멸율이 큰 마멸로 전이할 때 급격한 표면손상과 마찰계수의 급격한 증가를 동반하므로 이에 대한 해석에 중점을 두었다. 해석결과는 접촉하중과 마찰계수의 증가는 표면균열의 전파를 야기시켜 대규모 마멸입자를 생성시키게 됨을 보여주었다.

Wear Mechanism of CrN Coating on Aluminum Alloys Deposited by AIP Method

Kim, Seock-Sam,Suh, Chang-Min,Murakami, Ri-ichi Korean Tribology Society 2002 KSTLE International Journal Vol.3 No.1

Dry sliding wear and friction test of CrN coaling on two types of aluminum alloy substrates,6061 Al and 7075 Al deposited by arc ion plating, was peformed with a ball-on-disk tribometer. The effects of normal Bead and the mechanical properties of substrate on the friction coefficient and wear-resistance of CrN coating were investigated. The worn surfaces were observed by SEM. The results show that surface micro-hardness of CrN- coated 7075 Al is higher than that of CrN-coated 6061 Al. With an increase in normal lead, wear volume increases, while the friction coefficient decreases. The friction coefficient of CrN-coated 6061 Al is higher than that of CrN-coated 7075 Al, while the wear-resistance of CrN-coated 6061 Al is lower than the CrN-coated 7075 Al's, which indicates that the substrate mechanical properties have strong inf1uences on the friction coefficient and wear of CrN coating. The main wear mechanism was fragments of CrN coating, which were caused by apparent plastic deformation of substrate during wear test.

Tribological Characteristics of Magnetron Sputtered MoS$_2$ films in Various Atmospheric Conditions

Kim, Seock-Sam,Ahn, Chan-Wook,Kim, Tae-Hyung The Korean Society of Mechanical Engineers 2002 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.16 No.9

The friction and wear behaviors of magnetron sputtered MoS$_2$ films were investigated through the use of a pin and disk type tester. The experiments were performed for two kinds of specimens (ground (Ra 0.5 $\mu\textrm{m}$) and polished (Ra 0.01 $\mu\textrm{m}$) substrates) under the following operating condifions : linear sliding velocities in the range of 22~66 mm/s (3 types), normal loads varying from 9.8~29.4 N(3 types) and atmospheric conditions of air, medium and high vacuum (3types). Silicon nitride pin was used as the lower specimen and magnetron sputtered MoS$_2$ on bearing steel disk was used as the upper specimen. The results showed that low friction property of the MoS$_2$ films could be identified in high vacuum and the specific wear rate in air was much higher than that in medium and high vacuum due to severe oxidation. It was found that the main wear mechanism in air was oxidation whereas in high vacuum accumulation of plastic flow and adhesion, were the main causes of wear.