수복재료에 대합되는 의치용 레진치의 마모저항성 비교

이철영,정문규,Lee, Chul-Young,Chung, Moon-Kyu 대한치과보철학회 1999 대한치과보철학회지 Vol.37 No.3

The aim of this study was to compare wear resistance of resin denture teeth opposing various restorative materials. The wear resistance of conventional acrylic resin teeth(Trubyte Biotone) and three high-strength resin teeth(Bioform IPN, Endura, SR-Orthosit-PE) opposing different restorative materials(gold alloys, dental porcelain, composite resin) was compared. Wear tests were conducted with a sliding-induced wear testing apparatus which applied 100,000 strokes to the specimen in a mesio-distal direction under conditions of 100 stroke/min and constant loading of 1Kgf/tooth. Wear resistance of the resin denture teeth was evaluated by the following criteria : 1) wear depth, 2) weight loss, and 3) SEM observation. Results were as follows. 1. When opposed to gold alloys and composite resin, high-strength resin teeth showed superior wear resistance compared to acrylic resin teeth. But, in cases opposing dental porcelain, differences between the wear of the high-strength and acrylic resin teeth were not statistically significant (p<0.05). 2. When comparing wear resistance among high-strength resin teeth, opposing gold alloys, Endura was slightly more resistant and while in cases opposing dental porcelain, SR-Orthosit-PE was showed to be slightly resistant(p<0.05). 3. The wear of high-strength resin teeth was greater by 5 to 7 times when opposing porcelain and 2 to 3 times when opposing composite resin compared to gold alloys(p<0.05). 4. SEM observations of the wear surface showed that wear of resin teeth opposing gold alloys is a fatigue type of wear and wear of resin teeth opposing dental porcelain is fatigue and abrasion type of wear. Trubyte Biotone showed more severe fatigue type of wear than high-strength resin teeth. In conclusion, the use of dental porcelain should seriously be considered as restorative material in cases opposing resin denture teeth and improvement seems to be needed on resin teeth in the areas of wear resistance.

Effect of Homogenization Temperature on Microstructure and Mechanical Properties of Low-Carbon High-Boron Cast Steel

Fu Hanguang,Song Xuding,Lei Yongping,Jiang Zhiqiang,Xing Jiandong,Yang Jun,Wang Jinhua 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.3

The effects of quenching treatment on the microstructure, hardness, impact toughness, and wear resistance of low-carbon high-boron cast steel (LCHBS) containing 0.15-0.3 %C, 1.4-1.8 %B, 0.3-0.8 %Si, 0.8-1.2 %Mn, 0.5-0.8%Cr, 0.3-0.6%Ni, and 0.3-0.6%Mo have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and via an electron probe microanalyzer (EPMA), X-ray diffraction (XRD) analysis, impact tester, hardness tester, and wear tester. The as-cast matrix of LCHBS consists of pearlite and ferrite. There is 8-10 vol.% Fe2(B, C) type borocarbides in the matrix. The micro-hardness of Fe2(B, C) is 1430-1480 Hv. Fe2(B,C) shows no obvious change and the matrix completely transforms into lath martensite upon quenching at 900 °C to 1100 °C. The microhardness of the matrix and the macrohardness of the LCHBS sample show a slight increase with an increase of homogenization temperature. When the homogenization temperature exceeds 1050 °C, no distinct change in the hardness is observed. The change of homogenization temperature has no apparent effect on the impact toughness of LCHBS. The mass losses of LCHBS increase distinctly when the wear load increases. The homogenization temperature is less than 1000 °C and the wear rate of LCHBS decreases with an increase of temperature. The wear rate does not display any obvious change after exceeding a homogenization temperature of 1000 °C. The effects of quenching treatment on the microstructure, hardness, impact toughness, and wear resistance of low-carbon high-boron cast steel (LCHBS) containing 0.15-0.3 %C, 1.4-1.8 %B, 0.3-0.8 %Si, 0.8-1.2 %Mn, 0.5-0.8%Cr, 0.3-0.6%Ni, and 0.3-0.6%Mo have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and via an electron probe microanalyzer (EPMA), X-ray diffraction (XRD) analysis, impact tester, hardness tester, and wear tester. The as-cast matrix of LCHBS consists of pearlite and ferrite. There is 8-10 vol.% Fe2(B, C) type borocarbides in the matrix. The micro-hardness of Fe2(B, C) is 1430-1480 Hv. Fe2(B,C) shows no obvious change and the matrix completely transforms into lath martensite upon quenching at 900 °C to 1100 °C. The microhardness of the matrix and the macrohardness of the LCHBS sample show a slight increase with an increase of homogenization temperature. When the homogenization temperature exceeds 1050 °C, no distinct change in the hardness is observed. The change of homogenization temperature has no apparent effect on the impact toughness of LCHBS. The mass losses of LCHBS increase distinctly when the wear load increases. The homogenization temperature is less than 1000 °C and the wear rate of LCHBS decreases with an increase of temperature. The wear rate does not display any obvious change after exceeding a homogenization temperature of 1000 °C.

레이저 직접적층법으로 제조된 Fe-8Cr-3V-2Mo-2W합금의 마모특성에 미치는 열처리공정 및 상대재의 영향

하경식,박영근,김태환,백경윤,전종배,심도식,문영훈,이욱진 대한금속·재료학회 2020 대한금속·재료학회지 Vol.58 No.10

This study aimed to investigate the wear performance of laser direct energy deposited Fe-8Cr- 3V-2Mo-2W alloy under various wear environments, in terms of different heat treatment conditions. Ball on disk tribology tests were performed using high-carbon steel and zirconia balls as counter materials. The wear rates of the alloy depended significantly on both the wear sliding speed and the wear load. Microstructural observations of the worn surface and the wear debris indicated intensive tribo-oxidative wear that was presumably responsible for the strong dependency of the wear rate on the wear sliding speed. Regardless of the type of counter materials, the alloy in the as-built state had better wear performance than the alloy with heat treatments. Therefore, the use of the alloy without post heat treatment would be favorable to obtain long-term durability of the alloy in severe wear environments. The wear tests with two different counter materials of high-carbon steel and zirconia showed the highcarbon steel counter material had a higher wear rate than the zirconia. This was thought to be due to that strong third-body abrasive actions of the high-carbon steel counter material, evidenced by the severe abrasive wear of the counter material.

열처리된 고크롬 백주철/저크롬강 이중주조재료의 내마모성과 파괴인성

김창규,이성학,정재영 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.11

Wear resistance and fracture toughness of heat-treated duo-cast materials composed of a high-chromium white cast iron and a low-chromium steel were investigated in this study. Different size, volume fraction, and distribution of M7C3 carbides were employed to the wear resistant part by changing the amount of chromium and molybdenum, and the volume fraction of martensite in the austenitic matrix was varied by the heat treatment. In the alloys containing a small amount of chromium, a network structure of eutectic M_(7)C₃carbides was formed along solidification cell boundaries, and led to the improvement of wear resistance and fracture toughness. After the heat-treatment, the selective wear of the matrix and the cracking or fallen-offs of carbides were considerably reduced since the hardness difference between carbides and matrix decreased by the increase in the matrix hardness, thereby leading to the improvement of the wear resistance. However, the fracture toughness of the heat-treated alloys was lower than that of the as-cast alloys because the matrix containing a considerable amount of martensite did not prevent effectively the crack propagation. (Received July 20, 2004)

Hardness and wear resistance of steel-based surface composites fabricated with Fe-based metamorphic alloy powders by high-energy electron beam irradiation

Lee, Kyuhong,Nam, Duk-Hyun,Lee, Sunghak,Kim, Choongnyun Paul Elsevier 2006 Materials science & engineering. properties, micro Vol.428 No.1

<P><B>Abstract</B></P><P>In this study, steel-based surface composites were fabricated with Fe-based metamorphic alloy powders by high-energy electron beam irradiation, and their microstructure, hardness, and wear resistance were investigated. Two kinds of Fe-based metamorphic powders were deposited on a plain carbon steel substrate, and then electron beam was irradiated on these powders to fabricate one-layered surface composites. Two-layered surface composites were also fabricated by irradiating electron beam again onto the powders deposited on the one-layered surface composites. The composite layers of 2.6–3.1mm in thickness were homogeneously formed without defects, and contained a large amount (up to 64vol.%) of Cr<SUB>2</SUB>B or Cr<SUB>1.65</SUB>Fe<SUB>0.35</SUB>B<SUB>0.96</SUB> borides in the Cr<SUB>0.19</SUB>Fe<SUB>0.7</SUB>Ni<SUB>0.11</SUB> or martensite matrix. Since the hardness and wear resistance of the surface composite layers were directly influenced by hard borides, they were two to four times greater than those of the steel substrate. These borides also played a role in improving the high-temperature hardness because they are insoluble and thermally stable even at high temperatures. These findings suggested that various applications of the fabricated surface composites to materials requiring high resistance to heat and abrasion were expected.</P>

해양구조물강재의 절삭성능 평가

박광수,김영곤,주성민 조선대학교 공학기술연구원 2024 공학기술논문지 Vol.16 No.4

High-manganese steels designed to have an austenitic matrix structure are materials with excellent mechanical properties such as strength, toughness, and wear resistance. High manganese-containing steels with improved wear resistance are difficult to cut because they have low thermal conductivity and poor cold workability. Due to the strain hardening effect, wear resistance properties may further increase during the cutting process, which may adversely affect machinability and shorten cutting tool life. Correctly selecting the machining parameters of cutting tools is an important task. In this paper, we investigated the processing mechanism of high manganese steel applied to marine structures and analyzed wear characteristics.

용사 코팅된 스틸바의 트라이볼로지적 특성의 형상학적 관찰

이덕규(Duk Gyu Lee),조희근(Hee Keun Cho) 대한기계학회 2014 大韓機械學會論文集A Vol.38 No.5

제철공장의 소결대차 스틸바의 내열성, 내마모성, 내부식성 등의 성질을 향상시키기 위하여 용사코팅을 적용한 연구가 진행되었다. 약 700℃의 고온환경에서 내열, 내마모, 부식 등에 노출되어 있는 스틸의 표면에 Al₂O₃, Cr₂O₃, WC 코팅을 적용하여 국부적으로 고온내마모성, 내식성, 내열성, 내열충격성등을 향상시킴으로써 기존 제강공정에서 사용되는 스틸바의 수명을 향상시켰다. 스틸바에 적용한 금속용사 코팅층에 대하여 고온내마모시험, 열충격시험, 내부식시험을 수행하였다. 코팅층의 물리적, 화학적, 기계적 특성이 코팅이 안된 재료에 비해 매우 우수하였다. Plasma coatings have been conducted to improve the mechanical properties of thermal resistance, wear resistance, corrosion resistance and thermal shock with respect to Great-Bar which is used as a carrier device for ironstone sintering under 700℃. The surface coatings on the upper side of the Great-Bar exposed on extreme environments of high temperature, severe wear, corrosion and thermal shock extended the life time due to the barrier coating layer. Al₂O₃, Cr₂O₃, WC coatings were applied to Great-Bar and their mechanical and chemical properties are analyzed by several experimental tests such as thermal resistance, wear resistance, corrosion resistance and thermal shock resistance. It shows excellent advantages with respect to wear, thermal shock and corrosion.

이중복합 주조체의 제조에 미치는 구성 재질과 주조 조건의 영향

정재영 ( Jae-young Jung ) 한국주조공학회 2018 한국주조공학회지 Vol.38 No.2

In this study, the effects of the pouring temperature, preheating temperature, surface condition and fraction of the wear resistant part on the production of duo-castings were investigated using a high Cr white cast iron with excellent abrasion resistance and a low Cr alloy steel with good toughness. The constituent materials of the duo-castings were designed to have high hardness, fracture toughness and abrasive wear resistance for the replacement of high Mn alloy steels with low abrasive wear resistance. In particular, the amount of abrasive wear of 17% Cr white cast iron was about 1/20 of that of high Mn alloy steel. There was an intermediate area of about 3mm due to local melting at the bonding interface of the duo-castings. These intermediate regions were different from those of the constituent materials in chemical composition and microstructure. This region led to fracture within the wear resistant part rather than at the bonding interface in the bending strength test. The bending fracture strengths were 516-824 MPa, which were equivalent to the bending proof strength of high Mn steel. The effects of various casting conditions on the duo-cast behavior were studied by simple pouring of low Cr alloy steel melt, but the results proved practically impossible to manufacture duo-castings with a sound bonding interface. However, the external heating method was suitable for the production of duo-castings with a sound bonding interface.

이중복합 주조체의 제조에 미치는 구성 재질과 주조 조건의 영향

정재영 ( Jae-young Jung ) 한국주조공학회 2018 한국주조공학회지 Vol.38 No.1

In this study, the effects of the pouring temperature, preheating temperature, surface condition and fraction of the wear resistant part on the production of duo-castings were investigated using a high Cr white cast iron with excellent abrasion resistance and a low Cr alloy steel with good toughness. The constituent materials of the duo-castings were designed to have high hardness, fracture toughness and abrasive wear resistance for the replacement of high Mn alloy steels with low abrasive wear resistance. In particular, the amount of abrasive wear of 17% Cr white cast iron was about 1/20 of that of high Mn alloy steel. There was an intermediate area of about 3mm due to local melting at the bonding interface of the duo-castings. These intermediate regions were different from those of the constituent materials in chemical composition and microstructure. This region led to fracture within the wear resistant part rather than at the bonding interface in the bending strength test. The bending fracture strengths were 516-824 MPa, which were equivalent to the bending proof strength of high Mn steel. The effects of various casting conditions on the duo-cast behavior were studied by simple pouring of low Cr alloy steel melt, but the results proved practically impossible to manufacture duo-castings with a sound bonding interface. However, the external heating method was suitable for the production of duo-castings with a sound bonding interface.

HIPS 복합재의 전기적 및 마모 특성에 미치는 다중벽 탄소나노튜브의 영향

정연우(Yeon-Woo Jeong),김경식(Kyung-Shik Kim),이현우(Hyun-Woo Lee),정만우(Man-Woo Jeong),이재혁(Jae-Hyeok Lee),김재현(Jae-Hyun Kim),이학주(Hak-Joo Lee),김광섭(Kwang-Seop Kim) 한국트라이볼로지학회 2015 한국윤활학회지(윤활학회지) Vol.31 No.3

Carbon nanotubes (CNTs) are widely used in polymer composites as filler materials to enhance various characteristics of the composites because of their remarkable mechanical, electrical, and thermal properties. In this study, we investigate the effects of MWCNTs on the electrical and wear characteristics of high-impact polystyrene (HIPS) composites, and compare the results with the effects of carbon black (CB). The HIPS composites are classified as Bare-HIPS, MWCNT-HIPS composites containing 2, 3, 4, and 5 wt% MWCNTs, and CB-HIPS containing 17 wt% CB. Electrical characteristics are evaluated by measuring the surface resistance using a 4-point probe. Wear characteristics are evaluated using the reciprocating wear test, and a chrome steel ball with a curvature of 6.3 mm is used as the counterpart. The results show that the addition of MWCNTs or CB can improve the electrical and wear characteristics of HIPS composites. In the case of MWCNT-HIPS composites, surface resistance, friction coefficient, and specific wear rate decrease as the concentrations of MWCNTs increase. Moreover, the addition of MWCNTs is more effective in improving the electrical and wear characteristics of HIPS composites compared to the addition of CB. To fabricate the HIPS composite with appropriate electrical and wear characteristics, more than 4 wt% MWCNTs is added to HIPS.