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.

치약 성분이 미세 혼합형/나노필러 함유 복합레진의 칫솔질 내마모성에 미치는 영향

변선미,박정은,김경선,김태환,오정자,고승오,이민호 대한치과재료학회 2023 대한치과재료학회지 Vol.50 No.4

본 연구의 목적은 연마제 성분이 다른 치약들로 칫솔질 마모시험을 시행하여 미세 혼합형 및 나노필러 복합레진의 표면 형태와표면 거칠기를 관찰하고, 내마모성을 비교하는 것이다. 미세 혼합형 필러가 함유된 2종의 복합레진(Z100 Restorative, Filtek Z250)과 나노필러가 함유된 1종의 복합레진 (Filtek Z350 XT)을 사용하였다. 칫솔질 마모시험을 위해 직경 10 mm, 두께 1 mm의 복합레진 시편 90개를 준비했다. pin-on-disk 구동방식의 마모시험기를 사용하여 작용력은 2 N, 100,000회 칫솔질을수행하였다. 시험에 사용된 치약은 연마제 성분(하이드록시아파타이트, 탄산칼슘, 중탄산나트륨, 제올라이트-M)에 따라서 4 그룹으로 분류하였다. 칫솔질 마모시험 후 시편의 표면 형태는 광학현미경과 주사전자현미경(SEM)으로 관찰하였고, 원자힘현미경(AFM)으로 표면 거칠기를 측정하였다. 미세 혼합형 복합레진 그룹들의 표면에서는 상대적으로 큰 마이크로 필러 입자들이 돌출되어 있고, 작은 분화구 형태의 결함들이 관찰되었다. 제올라이트-M을 함유한 치약으로 마모시험을 시행한 그룹들의표면 거칠기 값이 유의하게 가장 높았다(P<0.05). 나노필러 함유 복합레진을 제올라이트-M이 함유된 치약으로 마모시험한 그룹에서 표면 거칠기 값이 유의하게(P<0.05) 가장 높았으나, 치약 종류와 상관없이 표면 거칠기가 0.1 µm 미만으로 낮은 값들을 나타냈다. 미세 혼합형 복합레진들의 표면에 비해 표면이 균일하고 매끄러워 보였다. 결과적으로, 나노필러 복합레진이 미세 혼합형 복합레진에 비해 상대적으로 더 높은 내마모성을 보였다. 이는 칫솔질 시의 마모 저항성이 재료의 임상적 내구성을나타낼 수 있다. The purpose of this study was to observe the surface morphology and roughness of micro-hybrid and nano-filled resin composites and compare wear resistance by conducting a toothbrushing wear test with toothpastes with different abrasive ingredients. Two types of resin composites containing micro-hybrid fillers (Z100 Restorative, Filtek Z250) and one type of resin composite containing nanofillers (Filtek Z350 XT) were used. For the toothbrushing wear test, 90 resin composite samples with a diameter of 10 mm and a thickness of 1 mm were prepared. A force of 2 N and 100,000 cycles of brushing were performed using a pin-on-disk wear tester. The toothpastes used in the test were classified into 4 groups according to the abrasive ingredients (hydroxyapatite, calcium carbonate, sodium bicarbonate, and zeolite-M). After the toothbrushing wear test, the surface morphology of the samples was observed using an optical microscope and a scanning electron microscope (SEM), and the surface roughness was measured using atomic force microscopy (AFM). Relatively large filler particles (micro size) protruded from the surface of the micro-hybrid resin composite groups, and small crater-shaped defects were observed. The surface roughness values of the groups that performed the wear test with toothpaste containing zeolite-M were significantly higher than the other groups (P<0.05). The surface roughness value was significantly (P<0.05) highest in the group where the nano- filled resin composite was wear-tested with toothpaste containing zeolite-M. However, regardless of the type of toothpaste, the surface roughness showed low values of less than 0.1 µm. The surface appeared uniform and smooth compared to the surface of micro-hybrid resin composites. Finally, the nano-filled resin composite showed relatively higher wear resistance than the micro-hybrid resin composite. This means that wear resistance during brushing may indicate the durability of the material in the clinic.

비회 운송관의 수명연장을 위한 유리섬유 복합재의 개발

정규상(Gyusang Jeong),장윤상(Yoonsang Chang) 한국청정기술학회 2009 청정기술 Vol.15 No.1

본 연구에서는 화력발전소에서 마모 및 주기적인 파손으로 문제가 발생하는 저회 운반용 주철관을 대체하기 위하여 내마모 성능이 우수한 FRP관을 개발하였다. 불포화 폴리에스테르, 비닐에스테르, 에폭시, 페놀 등 4종의 수지와 탄화규소 내마모재를 사용하여 시편을 제작하고 ASTM D4060 마모시험 및 분사식 마모시험을 수행하였다. ASTM D4060 마모시험에서는 최적의 수지 종류와 내마모재 크기, 내마모재와 수지의 혼합 비율을 찾고 내마모성을 극대화하였다. FRP와 주철을 비교한 시험에서는 FRP 시편이 주철 시편에 비하여 작은 마모량을 보여 주철관의 FRP 파이프로의 대체 가능성을 보여 주었다. 현장시험을 위하여 시제품 파이프를 제작한 후 기존 회처리라인에 적용한 결과 FRP관이 내마모성에서 기존의 주철관보다 우수함을 보여주었다. In this study, a fiber reinforced plastic (FRP) pipe with superior wear resistance was developed to replace the fly ash pipe of cast iron. Wear test was performed with various combinations of SiC filler and resin materials of unsaturated polyester, vinylester, epoxy, and phenol. Test results of ASTM D4060 showed the optimal combinations of resin, filler size, and resin/filler ratios. Test results of comparison between FRP and cast iron showed the possibility to replace cast iron pipe with the FRP pipe. Field test executed to compare the wear resistance between cast iron pipe and developed FRP pipe showed the superiority of the FRP pipe.

Review of the Wear Resistance

Seong-Mo Oh 한국기계기술학회 2013 한국기계기술학회지 Vol.15 No.2

알루미늄표면에 금속-세라믹입자 복합첨가에 의한 내마모성개선

이규천,박성두,이영호 대한용접접합학회 1997 대한용접·접합학회지 Vol.15 No.6

The present study was aimed to correlate the microstructure and the hardness as well as the wear resistance of the metal-ceramic particulated composite layer on the pure Al plate. The composite layers were constructed by the addition of TiC particles on the surface of Al-Cu alloyed layers by PTA overlaying process. Initially, the Al-Cu alloyed layers were achieved by the deposition of Al-(25 ~ 48%) Cu alloys on the pure Al plate by TIG process. It was revealed that TiC particles were uniformly dispersed without any reaction with matrix in the composite layer. The volume fraction of TiC particles (TiC V F) increased from 12% to 55% with increasing the number of pass of composite layer. Hardnesses of (Al-48%Cu + TiC (3&4layers)) composite layer were Hv450 and Hv560, respectively, due to the increase of TiC V/F. Hardnesses of (Al-Cu + TiC) composite layers decreased gradually with insreasing temperature from 100$^{\circ}$C to 400$^{\circ}$C, and hardnesses at 400$^{\circ}$C were then reached to 1/5 - 1/10 of room temperature hardness depending on the construction of composite layers. The Specific wear of (Al + Tic) layer and Al-48%Cu alloyed layer decreased to 1/10 of the of pure Al, while the specific wear of (Al-48%Cu + TiC (4 layers)) composite layer exhibited 1/15 of that of steel such as SS400 and STS304.

내마모성이 우수한 스포츠화 스터드 개발

박승빈(S. B. Park),이준서(J. S. Lee),송정일(J. I. Song) 한국기계가공학회 2014 한국기계가공학회 춘추계학술대회 논문집 Vol.2014 No.11

니켈 합금 용접이 금형 표면의 균열 발생에 미치는 영향

정혜동(Hyae-Dong Jeong),이지훈(Ji-Hoon Lee),홍민성(Min-Sung Hong) 한국생산제조학회 2011 한국생산제조학회지 Vol.20 No.4

Cast mold has low wear-resistance comparing with other alloyed molds which result in lower production rate and high cost of products. Recently, various weld methods are being applied to increase the wear-resistance of molds and to extend mold life. Among them, nickel alloy weld process increases the hardness irrelevant to its machinability and creates very uniform structures. In addition, it causes better wear-resistance and reduces shrinkage defects. In this paper, we analyze the mold surface cracks welded by nickel alloy and propose the methods to improve the mold surface and its wear-resistance. It has been found that nickel alloy weld does not affect the inside crack of mold but has an influence on the surface crack seriously. Results show that the start and growth of fatigue cracks have been delayed about 3 times and reduced approximately 75%, respectively, and the mold surface cracks are decreased about 5.7 times.

금형재료용 주철의 레이저 표면경화처리시 재료에 따른 열처리 특성

김종도(Jong Do Kim),송무근(Moo Keun Song),황현태(Hyun Tae Hwang) 대한기계학회 2011 大韓機械學會論文集A Vol.35 No.12

자동차 차체를 제작하는 프레스 금형의 가공공정 중 제품의 형태를 완성하는 드로잉 공정 및 불필요한 부분을 절단하는 트리밍 공정은 그 공정의 특성상 금형의 마모가 심하기 때문에 금형의 내마모성을 향상시키기 위한 표면경화처리가 요구되고 있다. 따라서 본 연구에서는 프레스 금형에 레이저 표면처리기술을 적용하기 위한 실험을 실시하였다. 드로잉 공정 및 트리밍 공정에 적합한 표면경화처리를 위해 다이오드 레이저를 이용하여 시험편의 평면부 및 모서리부를 열처리하였으며, 각각의 적정 열처리 조건을 도출하였다. 또한 시험편의 재료에 따른 열처리 특성을 비교하기 위해 구상흑연 및 편상흑연 주철을 사용하여 실험을 진행하였다. 실험 결과, 재료에 따른 열처리 특성에 차이가 있다는 것을 확인하였으며, 적정 열처리된 조건에서의 경화부는 모재에 비하여 약 3배 정도의 경도상승을 나타내었다. Surface hardening treatment is required to improve the wear-resistance of press die because severe abrasion of die occurs during the drawing process in which the forming of the automotive body is completed and during the trimming process in which the unnecessary parts are cut. In this study, experiments on the laser surface treatment of press die are performed. Specimens are heat-treated separately at certain plate and edge position by using a diode laser to carry out suitable surface hardening treatment to reduce the wear during the drawing and the trimming processes, and the proper conditions for heat treatment are found. Spheroidal and flake graphite cast iron specimens are used, and the heat treatment characteristics of the two materials are compared. From the results of the study, it is confirmed that the heat treatment characteristics differed depending on the materials.

경질 박막을 코팅한 H13 열처리재의 내마모성

김경현(Kyung hyun Kim),이규용(Kyu yong Lee) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.4

Candidate coatings on H13 steel substrates aimed at improving the tribological performance of die casting dies for the industry have been extensively characterized. In order to reduce wear they are almost always surface treated by various forms of heat-treatment. Surface-coating by physical vapour deposition(PVD) or chemical vapour deposition(CVD) is currently being introduced as a means to further improve the wear resistance. In this paper a pin-on-disk configuration at speed of 0.1 ㎧ with load of 1.51N was employed to study the wear behavior. Vickers microhardness was measured using a load of 9.8N and an average of three readings was taken.

금형재료용 주철의 다이오드 레이저 표면경화처리에 관한 연구(Ⅲ)

김종도(Jong-Do Kim),송무근(Moo-Keun Song),황현태(Hyun-Tae Hwang) 한국마린엔지니어링학회 2012 한국마린엔지니어링학회지 Vol.36 No.1

Mold may experience deterioration of molding quality as the abrasion of mold occurring due to friction between mold and molded product works as allowance in the course of press process. Therefore, to improve the wear-resistance of mold, methods like nitriding, carburizing, flame and induction surface hardening treatment etc have been applied. However, as such methods are accompanied by problems like shape limitation or product deformation etc, laser surface treatment technology is under review as surface treatment method that can solve such problems. Therefore, in this study, mold material cast iron was surface-treated by using high power diode laser. In previous report 1 and report 2, the heat treatment characteristics were compared by the differences of die materials and shapes, then this paper observed microstructure by using optical microscope and scanning electronic microscope to analyze the structural difference of hardened zone, interface area and base metal after heat treatment. And the structural condition was grasped through EDS. As a result of microstructure, hardened zone showed formation of acicular martensite.