옻칠 고온경화기법을 활용한 알루미늄 표면장식에 관한 연구

김대건,차경철 사단법인 한국조형디자인협회 2019 조형디자인연구 Vol.22 No.4

본 연구는 알루미늄 표면 질감과 고온경화 환경에 따른 옻칠고온경화기법의 도막형성과 강도 및 접착력 정도를 알아보기 위한 것이다. 알루미늄은 다른 금속에 비해 가볍고, 가공성이 우수하며, 비교적 경제적인 소재로서 일반 산업 소재뿐만 아니라 금속 조형작업에도 적합하여 금속제 가구, 조명, 장신구 등에 널리 사용되고 있다. 알루미늄 판재를 가공하여 입체형태로 만들기 위해서는 판재를 절곡, 밴딩, 망치성형과 용접 작업을 병행하게 된다. 이렇게 용접 부분이 형성된 작업물의 접합한 부분에는 양극산화기법을 적용하게 되면 얼룩이 생기게 되어 원하는 색상 표현에 문제점이 발생한다. 합성수지도료를 사용하는 도장법을 활용하여 작업의 색상을 표현할 수 있지만, 금속 조형작업의 마감 표면착색 기법으로써 아쉬운 점이 있다. 이러한 아쉬움에 본 연구자는 알루미늄 판금 성형 작업에 적용할 수 있는 고급스러우며 부가가치가 높은 알루미늄 표면처리 방법에 대하여 연구를 하였다. 여러 금속 공예가들은 색상의 다양한 표현을 위해 여러 가지 방법을 사용하고 있다. 그 중 전통적이며 친환경적인 소재인 옻칠을 작업에 적용하는 것을 볼 수 있다. 옻칠은 역사적 가치와 강한 접착력과 내구성 등 여러 우수성을 지닌 전통적인 소재이며 색상표현 및 광택도의 고급스러움으로 알루미늄 금속 조형작업의 표면마감 기법으로 적합하다. 금속 소재에 옻칠을 안착시키기 위해서는 가마나 가스토치 등 가열경화 하는 방법을 사용한다. 일정의 고온이 유지되어 옻칠이 금속 표면에 접착이 되는데, 가열경화의 환경과 표면질감은 도막형성에 영향을 준다. 옻칠의 가열경화 환경과 알루미늄 표면질감이 옻칠의 도막형성에 어떻게 영향을 주는지 확인하기 위해 가열경화 환경으로 가열시간과 가열온도의 변화를 주어 실험하였고, 알루미늄 표면질감으로 정제된 판, #320 사포 연마된 상태, 모래맞춤가공 상태, 망치 질감 4가지 상태로 나뉘어 실험하였다. 4가지 알루미늄 표면질감과 경화 시간과 경화 온도에 따른 도막형성 정도의 시편을 만들었고, 만들어진 시편에 연필 강도 실험과 크로스커트 실험을 통해 알루미늄 표면과 옻칠고온경화 환경에 따른 접착력 및 강도 실험 결과를 도출하였다. 옻칠의 가열경화 환경 중 가열시간 보다는 일정 가열온도에 따라 접착력이 높은 도막을 형성하였고, 광택이 난 표면질감은 사포연마와 망치 질감보다 접착력이 떨어졌으며, 모래맞춤 가공된 상태의 표면질감이 가장 접착력이 높은 것을 확인할 수 있었다. 실험을 통하여 옻칠의 가열경화 환경과 알루미늄 표면상태에 따라 옻칠의 강도와 접착력이 다름을 파악할 수 있었다. 다양한 알루미늄 판금성형에 옻칠을 적용은 금속작업의 경량화, 색상표현의 다양화 등의 장점을 갖추며, 장식적이고 부가가치가 높은 표면처리로 알루미늄 판금성형 작업의 심미성을 더하고 그 가치를 높일 수 있으리라 기대한다. This study aims to identify film formation, intensity and adhesion degree of the high temperature hardening technique of a Otchill according to a surface texture of aluminum and a high temperature hardening environment. Aluminum has advantages over other metals, for instance, lighter weight, more excellent machinability and relatively cheaper price. Therefore, it is widely used in metallic furniture, lighting devices or stylish accessories because it is suitable for not only a general industrial material but also metallic molding works. In order to fabricate a specific conformation shape by processing aluminum plates, it is required to perform several different works on the plates such as cutting, bending, hammering formation and welding. If an anodic oxidation method is applied in such a welded part of the fabricated object, a stain occurs to cause problems in representing the color wanted. Although, of course, there is a way to represent the color of work through a painting of synthetic resin paints, it is not sufficient as a finishing surface coloring technique of metallic formation works. In this regard, the researcher has studied on the surface treatment method of aluminum that is a luxurious and highly value added material, and that can be applied in a sheet metal formation works. Many metal craftsmen use a variety of methods for various representations of colors. Of those, it is sometimes possible to see that a Otchill, which is a traditional and eco-friendly material, is applied in the works. Lacquer is a traditional material that shows off many superiorities including traditional values, strong adhesion and durability, in addition, it is appropriate to a surface finishing material of metallic formation works using aluminum due to its luxurious sensation in terms of color representation and brilliance. Hardening with heating methods such as kilns or gas torches are typically required in order to stain a metallic material with a Otchill. In other words, a Otchill can be stained on the metal surface by maintaining a specific high temperature and the film formation is affected by environment of heat hardening and surface texture. To identify the impacts of both heat hardening environment by a lacquer and surface texture of aluminum on the film formation in a lacquer, experiments were conducted by altering the heating time and temperature under the environment of heat hardening. The experiments were conducted by dividing into 4 states, including a refined plate with surface texture of aluminum, a ground state by the #320 sandpaper, a state by sandblast processing and a hammer texture. The specimens, which are in line with film formation degrees according to the 4 different surface textures of aluminum as well as the time and temperature for hardening, were fabricated. With these specimens fabricated, the experiment results on adhesion and strength according to the aluminum surface and high temperature hardening environment for a Otchill were derived through a strength experiment of a pencil and crosscut experiment. The film with a higher adhesion was formed with the specific heating temperature rather than the heating time among environmental factors for heat hardening of a Otchill. In addition, it was confirmed that a surface texture showing a brilliance had less adhesion than sandpaper grinding or hammering texture and the surface texture of sandblast processing exhibited the highest adhesion. It was possible to identify through the experiments that strength and adhesion of a lacquer varied according to the heat hardening environment of a Otchill and surface status of aluminum. It is anticipated that applying a Otchill on various aluminum plate moldings will not only increase the aesthetic impression of a plate molding work of aluminum but also heighten its value because it has advantages of weight lightening of metallic works, a diversity of color representation and the ornamental and high value-added surface tre...

레이져 표면 경화 공정에서 신경회로망을 이용한 경화층 깊이 예측

우현구,조형석,한유희,Woo, Hyun Gu,Cho, Hyung Suck,Han, You Hie 한국정밀공학회 1995 한국정밀공학회지 Vol.12 No.11

In the laser surface hardening process the geometrical parameters, especially the depth, of the hardened layer are utilized to assess the integrity of the hardening layer quality. Monitoring of this geometrical parameter ofr on-line process control as well as for on-line quality evaluation, however, is an extremely difficult problem because the hardening layer is formed beneath a material surface. Moreover, the uncertainties in monitoring the depth can be raised by the inevitable use of a surface coating to enhance the processing efficiency and the insufficient knowledge on the effects of coating materials and its thicknesses. The paper describes the extimation results using neural network to estimate the hardening layer depth from measured surface temperanture and process variables (laser beam power and feeding velocity) under various situations. To evaluate the effec- tiveness of the measured temperature in estimating the harding layer depth, estimation was performed with or without temperature informations. Also to investigate the effects of coating thickness variations in the real industry situations, in which the coating thickness cannot be controlled uniform with good precision, estimation was done over only uniformly coated specimen or various thickness-coated specimens. A series of hardening experiments were performed to find the relationships between the hardening layer depth, temperature and process variables. The estimation results show the temperature informations greatly improve the estimation accuracy over various thickness-coated specimens.

다이오드 레이저를 이용한 탄소강 환봉의 표면변태 경화특성

김종도(Jong-Do Kim),강운주(Woon-Ju Kang),이수진(Su-Jin Lee),윤희종(Hee-jong Yoon),이제훈(Jae-Hoon Lee) 한국레이저가공학회 2008 한국레이저가공학회지 Vol.11 No.4

Laser Transformation Hardening(LTH) is one branch of the laser surface modification processes. A lot of energy is needed for the LTH process to elevate workpiece surface to temperature of the austenite transformation(A₃), which results from utilizing a beam with a larger size and lower power density comparatively. This study is related to the surface hardening for the rod-shaped carbon steel by the high power diode laser whose beam absorptivity is better than conventional types of lasers such as CO₂or Nd:YAG laser. Because a beam proceeds on the rotating specimen, the pretreated hardened-phase can be tempered and softened by the overlapping between hardened tracks. Accordingly, the longitudinal hardness measurement and observation of the micro structure was carried out for an assessment of the hardening characteristics. In addition, a hardening characteristics as a hardenability of materials was compared in the point of view of the hardness distribution and hardening depth and width.

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.

증기 터빈 동익 재료인 12Cr 강의 화염표면 처리에 의한 열 이력 제어 및 경화 특성에 관한 연구

이민구,김광호,김경호,김흥회 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.11

Low carbon 12Cr steel used as a nuclear steam turbine blade material have been surface-modified by the flame hardening process and the properties of hardness, hardening depth, and residual stress have been studied. For this, the thermal cycles of 12Cr steel have been controlled precisely as a function of the surface temperature, the exposed height from the water surface, and the cooling rate. The application of flame hardening increases the hardness of 12Cr steel (base value, 250 HV) to 420~550 HV considerably, forming relatively sharp hardening boundaries. Both the hardening depth and the austenitization period are linearly correlated well within the range of processing conditions employed. The rapid cooling rate also increases the hardening depth as well as the surface hardness. The properties of residual stress are discussed in terms of contributions of both the thermal and transformation stress components. The optimum processing conditions for the desirable residual stress state in the material are as follows : less than 1200℃ for the 18 mm-exposed and less than 1150℃ for full-exposed conditions by the criteria of Siemens AG-KWU, and on the basis of the specification of GE Power Generation Engineering, 944~1050℃ for the 10 mm-exposed, 883~1150℃ for the 14 mm-exposed, 833~1134℃ for the 18 mm-exposed, and 785~1097℃ for the full-exposed.

동결융해 환경에서의 제설염 종류와 표면강화제 처리에 따른 콘크리트의 표면박리 저항성 및 평가방법에 관한 연구

이현기(Lee, Hyeongi),이인희(Lee, Inhee),이종미(Lee, Jongmi),오홍섭(Oh, Hongseob) 한국방재학회 2017 한국방재학회논문집 Vol.17 No.4

본 연구의 목적은 제설염의 종류 및 구체강화제의 처리 유무에 따른 콘크리트 표면 박리저항성을 평가하고, 3D 스캐닝에 의해 표면상태를 평가하는 기법을 제안하고자 하였다. 본 연구에서는 국내에서 많이 사용되고 있는 다양한 습염식 제설염을 국외의 스케일링 시험법에 따라 콘크리트 표면에 표면강화제를 변수로 하여 박리실험을 실시하였다. 실험결과 무기질계 구체강화제를 사용한 경우 스케일링 저항성이 크게 향상되는 것으로 나타났으며, 규산나트륨계열의 강화제의 경우에는 박리가 상대적으로 많이 진행되었다. 또한 본 연구에서는 콘크리트 표면 박리를 평가하기 위하여 3D 스캐닝을 사용하여 박리량을 평가하는 법을 제안하고자 하였다. The objectives of this research study were to evaluate and discuss the scaling resistance of concrete surface due to freeze-thaw effect according to both the type of saline solution that was applied in compliance with overseas standards, and the treatment of the concrete surface hardener. Further, the accuracy of the evaluation method was assessed utilizing 3-D imaging technologies to determine the scaling resistance of concrete surface. This research study comparatively analyzed the scaling resistance of concrete surfacefor deicing agents that are currently used in domestic pre-wetting spray systems. Comparisons were made according to the saline solution that is used in compliance with overseas scaling resistance evaluation standards, the type of concrete surface hardener used, and whether the concrete had undergone a surface treatment. The results based on the concrete surface hardener treatment manifested superior results when mineral silane-based treatment agents were used. In order to provide a more quantitatively reliable evaluation, a concrete surface scaling resistance evaluation method utilizing 3-D scanning technologies was proposed in this research study.

Ti-6Al-4V 합금의 표면 경화 시 경화기구 및 공정변수가 표면 경화에 미치는 영향

서동명,윤혜정,황태우,문영훈 한국소성∙가공학회 2019 소성가공 : 한국소성가공학회지 Vol.28 No.1

The effect of hardening methods and process parameters on surface hardening of a Ti-6Al-4V Alloy has been investigated in this study. To characterize the effectiveness of the respective surface hardening methods, samples of a Ti-6Al-4V alloy were self-quenched, laser-nitrided, laser-carburized, laser-carbonitrided at the same laser irradiation conditions. This experimental procedure was followed by comparing the microstructural evolutions and mechanical properties of the respective samples after the laser surface hardenings. The hardening characteristics of the respective laser surface hardenings were well defined in this study, and the hardness was significantly influenced by the reaction compounds and laser energy density.

Research on the Surface Characteristics of Hardened Steel with Variable Chamfer Edge PCBN Insert by High-Speed Hard Turning

Xian-li Liu,Su-Yan Li,Tao Chen,Dao-Yuan Wang 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.2

In this paper, high-speed cutting tests for hardened steel were carried out where PCBN inserts with variable chamfer and fixed chamfer were employed. The aim of the tests was to investigate the influence of cutting speed and tool wear of variable chamfer insert on the machined surface topography, micro-characteristics and micro-hardness, where comparison and analysis of the machined surface properties were also carried out for the surface produced by the fixed chamfer tool. Experimental results showed that machined surface morphologies become more complex and rough, and peaks appear to a trend towards steepness, with the flank wear increase of the variable chamfer tool. At the same time, the thickness of white layer, hardening depth and hardening degree of the machined surface increase dramatically. With the increase in cutting speed of the variable chamfer tool, it is of primary importance to consider phase transition effects caused by thermal load, which will result in increase in the thickness of white layer on the machined surface. Moreover, it will also lead to decrease in the thickness and deformation degree of plastically deformed layer caused by mechanical load. Compared to the fixed chamfer tool, the cutting force generated by the variable chamfer tool is relatively small, where the flank wear area is also smaller and the groove wear marks is shallower. Therefore, better surface roughness can be obtained by utilizing the variable chamfer tool. In particular, the gap between the roughness of the machined surface formed by two tools becomes more pronounced in the scenarios of high speed and severe wear. Moreover, the thickness of white layer, the depth and degree of hardened layer are relatively small for the variable chamfer tool. Therefore, the surface properties produced by the variable chamfer tool would be more desirable.

Some characteristics of materials surface-modified by ions beam bombardment

Park, J.W.,Sohn, C.W.,Choi, B.H. Elsevier 2006 CURRENT APPLIED PHYSICS Vol.6 No.2

<P><B>Abstract</B></P><P>Ion implantations with energies less than 100keV and current densities of 10<SUP>15</SUP>–10<SUP>18</SUP>ions/cm<SUP>2</SUP> were conducted to polymers, metals, and diamond gemstone. Physical and chemical phenomena and mechanical properties of the implanted materials were investigated.</P><P>Single or mixed ions of N, He, C were implanted onto polyethylene terephtalate (PET) to see the surface hardening effects. Multiple ion-implantation resulted in more increase in the surface hardness than single ion implantation at the same ion energy and dose. Implantation of C+N ions increased the surface hardness by about three times as compared to implantation of N or C ions alone. XPS analysis showed that C–N compounds were formed when both N and C ions are implanted into PET, implying that hard particle formation by reactions between the implanted ions and/or between the implanted N ions and carbon in PET in addition to the cross linking may be the mechanism of this significant increase in hardness.</P><P>Ion implantation with 70keV N ions of >5×10<SUP>16</SUP>/cm<SUP>2</SUP> into the surface-polished stainless steel reduced the average surface roughness (<I>R</I><SUB>a</SUB>) from 0.04μm to 0.02μm. The implanted nitrogen was detected up to at least 300nm from the surface of the stainless steel as measured with Auger electron spectroscopy. X-ray photo-electron spectroscopy analysis showed that the implanted N formed mostly Cr<SUB>2</SUB>N without post irradiation annealing. Hardness depth profiles obtained with nano-indentation technique showed that the peak hardness of 14Gpa formed at ≈50nm depth from the N ion implanted surface was about at least 2 times higher than non-irradiated specimen.</P><P>N ions were implanted into the diamond in order to change the optical band gap and then to change the emitted color. In spite of the restricted ion penetrated depth, uniform and vividly changed color was observed after heat treatment of the nitrogen-implanted diamond in the vacuum or inert gas atmosphere. The changed color appeared to be black. Chemical states of the implanted nitrogen were N–N and 4N-vacancy as characterized with FTIR. Band structure calculation shows that band gap of the diamond reduced by 25% after N doping.</P>

석고 다이에 대한 다이 강화제의 영향

김영림,박주미,송광엽,Kim, Young-Rim,Park, Ju-Mi,Song, Kwang-Yeob 대한치과보철학회 2007 대한치과보철학회지 Vol.45 No.4

Statement of problem: Die materials require abrasion resistance, dimensional stability with time, and high surface wettability for adequate material properties. Wear of gypsum materials is a significant problem in the fabrication of accurately fitting cast prosthetic devices. So It has been recommended that the use of die hardener before carving or burnishing of the wax pattern. Purpose: The purpose of this study was to compare the abrasion resistance and surface microhardness(Knoop) with 3 commonly used gypsum die materials(MG Crystal Rock, Super plumstone, GC $FUJIROCK^{(R)}$ EP) with and without the application of 2 die hardeners. Material and methods: Three die materials were evaluated for abrasion resistance and surface microhardness after application of 2 die hardeners(Die hardener and Stone die & plaster hardener). Thirty specimens of each gypsum material were fabricated using an impression of resin die(Pattern resin; GC Corporation, Japan) with 1-mm high ridges, sloped 90 degrees. Gypsum materials were mixed according to manufacturer's recommendations and allowed to set 24 hours before coating. Specimens were arbitrary assigned to 1 of 3 treatment subgroups (n=10/subgroup): no treatment(control), coated with Die hardener, and coated with Stone die & plaster hardener. Abrasion resistance(measured by weight loss) was evaluated using device in 50g mass perpendicular to the ridges. Knoop hardness was determined by loading each specimen face 5 times for 15 seconds with a force of 50g. A scanning electron microscope was used to evaluate the surface of specimens in each treatment subgroup. Conclusions: The obtained results were as follows: 1. 3 types of die stone evaluated in this study did not show significant differences in surface hardness and abrasive resistance(P<.05). 2. In the abrasive resistance test, there were no significant differences between GC $FUJIROCK^{(R)}$ EP and MG Crystal Rock with or without 2 die hardener(P<.05). 3. Super plumstone treated with Stone die & plaster hardener showed increased wear loss(P<.05) 4. Die hardener coatings used in this study decreased the surface hardness of the gypsum material(P<.05).