전자처리 스페클 패턴 간섭법(ESPI)을 이용한 3-유닛 고정성 국소의치의 변형특성 분석

강후원,이철민,양승필,김희진 대한치과기공학회 2013 대한치과기공학회지 Vol.35 No.1

CAD/CAM 및 카피밀링 시스템을 이용하여 제작한 구치부 3-유닛 고정성 국소의치의 파절강도

강후원,김희진,김장주,고명원 대한치과기공학회 2012 대한치과기공학회지 Vol.34 No.2

치과용 고주파 주조기를 이용한 Co-Cr-Mo계 합금 용해과정의 적외선 열화상 분석

강후원,박영식,황인,이창호,허용,원용관 대한치과기공학회 2014 대한치과기공학회지 Vol.36 No.3

Purpose: Dental casting Co-Cr-Mo based alloys of five kinds of ingot type and two kinds of shot type were analyzed the melting processes with heating time of high frequency induction centrifugal casting machine using infrared thermal image analyzer. Methods: When Co-Cr-Mo based alloys were put about 30g/charge in the ceramic crucible of high frequency induction centrifugal casting machine and heat, Infrared thermal image analyzer and IR thermometer indicated these alloys in the crucible were set and operated. Results: The melting temperatures of alloys measuring infrared thermal image analyzer were deviated ±10℃ compared to those of manufacturing company. On the other hand, the melting time of alloys were differently appeared with the shape of alloys(ingot and shot type). Conclusion: The melting temperatures of dental Co-Cr-Mo based alloys were measured the degree of 1,360~1410℃ and the heating time with the alloys of ingot and shot type were deviated ±10 sec.

Sn 및 Cu를 첨가한 치과 주조용 Co-Cr-Mo계 합금제조 및 용해과정 분석

강후원,박영식,황인,이창호,허용,원용관 대한치과기공학회 2014 대한치과기공학회지 Vol.36 No.3

Purpose: Dental casting #GrⅠ(Co-25Cr-5Mo-3Sn-1Mn-1Si), #GrⅡ(Co-25Cr-5Mo-5Cu-1Mn -1Si) and #GrⅢ (Co-25Cr-5Mo-3Sn-5Cu-1Mn-1Si) master alloys of granule type were manufactured the same as manufacturing processes for dental casting Ni-Cr and Co-Cr-Mo based alloys of ingot type. These alloys were analyzed melting processes with heating time of high frequency induction centrifugal casting machine using infrared thermal image analyzer. Methods: These alloys were manufactured such as; alloy design, the first master alloy manufatured using vacuum arc casting machine, melting metal setting in crucible, melting in VIM, pouring in the mold of bar type, cutting the gate and runner bar and polishing. These alloys were put about 30g/charge in the ceramic crucible of high frequency induction centrifugal casting machine and heat, Infrared thermal image analyzer indicated alloys in the crucible were set and operated. Results: The melting temperatures of these alloys measuring infrared thermal image analyzer were decreased in comparison with remaniumⓇ GM 800+, vera PDITM, BiosilⓇ f, WISILⓇ M typeⅤ, Ticonium 2000 alloys of ingot type and vera PDSTM(Aabadent, USA), Regalloy alloys of shot type. Conclusion: Co-Cr-Mo based alloy in addition to Sn(#GrⅠ alloy) were decreased the melting temperature with heating time of high frequency induction centrifugal casting machine using infrared thermal image analyzer.

Fe-Mn-Si계 합금의 형상기억능에 미치는 변형온도 및 training 효과

강후원,한재익,장우양,강조원 조선대학교 생명과학연구소 2000 生産技術硏究 Vol.22 No.1

The shape memory effect is resulted from the reverse motion of Shockley partial dislocations which change εmartensite back to austenite. In Fe-Mn-Si alloys, the shape memory effect is obtained by the reverse transformation of stress-induced E martensite during heating. The reversibility of the motion of partial dislocations will not lead to a complete recovery. There are many factors influencing the shape memory effect like as alloy composition, Neel temperature, transformation temperature, applied stress and strain, annealing and quenching temperature, deformation and recovery annealing temperature etc. In this paper, shape memory effect by training treatment(cold working- annealing) and deformation temperature between -20℃ and 200℃ with amount of strain was improved in Fe-l5Mn-5Cr-10Co-3Si alloys Training treatment suppresses slip deformation and lower the stress for induced εmartensite transformation through introducing the stacking faults which can act as nucleation embryo for εmartensite.

Fe - X%Mn - 5Cr - 5Co - 4Si 합금 리본의 변태특성 및 형상기억능에 미치는 열처리 영향

강후원(H . W . Kang),지광구(K . K . Jee),장우양(W . Y . Jang),강조원(J . W . Kang) 한국열처리공학회 2001 熱處理工學會誌 Vol.14 No.3

N/A The change of ribbon geometry, microstructure and shape recovery with Mn contents, wheel speed and various annealing temperature have been studied in Fe-X%Mn-5Cr-5Co-4Si(X%=15, 20, 24) shape memory alloy (SMA) ribbons rapidly solidfied by single roll chill-block melt-spinning process. The thickness and width of melt-spun ribbons are reduced, results in refining and uniformalizing grains with increasing wheel speed. In the ribbons melt-spun at a wheel speed of 15m/sec, both a and α`martensites are formed in ribbon 1 (15.5wt%Mn), while only ε martensite is revealed in ribbon 2 (20.2wt%Mn) and ribbon 3 (23.5wt%Mn). The volume fraction of a martensite is decreased with increasing Mn contents, and those of ε as well α`martensites are increased due to thermal stress relief and grain growth with increasing annealing temperature. Mn temperatures of the ribbons 1, 2 and 3 are fallen with increasing Mn contents. M_s temperatures of the ribbons 1, 2 and 3 annealed at 300℃ for 3min are risen abruptly, but are nearly constant even at higher annealing temperature, i.e., 400, 500 and 600℃ for 3 min. Shape recovery of the ribbons 1, 2 and 3 increased 30%, 52% and 69% with Mn contents, respectively. Shape recovery of ribbon 1 (15.5wt%Mn) formed ε and α`martensites decreased because of the presence of α`martensite but those of ribbon 2 (20.2wt%Mn) and ribbon 3 (23.5wt%Mn) formed ε martensite increased with increasing annealing temperature.

CuAlNi 형상기억합금의 결정립 크기 및 제 특성에 미치는 가공열처리의 영향

이영수,강후원,김윤채,장우양,강조원 조선대학교 생산기술연구소 1996 生産技術硏究 Vol.18 No.1

The effect of thermomechanical treatment such as hot-rolling and subsequent annealing conditions has been studied. and the variations of mechanical properties. transformation temperature and shape memory ability with annealing time have been investigated in CuAlNi shape memory alloys by metallography. calormetry and X-ray diffraction. The grain of the specimen hot-rolled below 800℃ was deformed and elongated but the grain of the specimen hot-rolled above 800℃ was partially recrystallized. The grain size after hot-rolling decreased with decreasing hot-rolling temperature and with increasing the rate of reduction in thickness. By the chage of cooling rate after hot-rolling, the microstructure of the hot-rolled specimen could be controlled and it has affected grain size during recrystallization. The grain size could be markedly decreased by intermediate annealing between hot rolling process; the smallest grain with the size of 95㎛ could be obtained by recrystallization at 700℃ for 7min after the combination of intermediate annealing and hot-rolling process. With increasing recrystallization time. M_(s) and A_(s) temperatures increased but transformation hysteresis decreased. The difference in the fracture surface could be clearly observed with recrystallization time. With increasing annealing time in order of 3min, 5min and 7min at 700℃. the fracture mode has changed to the mixture of intergranular and transgranular fracture with the latter being dominant, to transgranular fracture and to intergranular fracture, respectively. In the case of annealing at 700℃ for 5min. shape memory ability could be obtained maxium value by 74% but it was sligtly decreased to 60% with increasing time.

치과주조용 Ti-Zr-Cr계 합금에서 Cr 함량변화가 부식저항성에 미치는 영향

박영준,강후원,이용렬,송호준,김민강 大韓齒科器材學會 2004 대한치과재료학회지 Vol.31 No.4

The purpose of this study was to develop new dental casting titanium (Ti) alloys having an excellent mechanical properties and good corrosion resistance as a substitute for c.p Ti and Ti-6Al-4V alloy (control groups). Ti-20Cr, Ti-2OZr and Ti-20Zr-XCr (X=2, 5, 10, 15) alloys (experimental groups) were designed for dental casting Ti alloys. Prior to casting prccedure, mother alloys were prepared by using vacuum arc melting with skull melting method. Argon-arc melting and argon/vacuum-pressure casting machine were used for making the specimens. The hardness, microstructure, and corrosion resistance were evaluated by using Vickers microhardness measurement, FE-SEM, and anodic polarization test. The results were as follows: 1. The Vickers microhardness (Hv) of Ti and Ti-6Al-4V alloy showed the values of 210 and 352, and Ti-20Cr and Ti-20Zr alloys showed the values of 341 and 259, respectively. As the Cr content increased from 0 to 15 % in Ti-20Zr-XCr (X=0, 2, 5, 10, 15) alloys, the Hv increased from 259 to 298, 457, 344, and 351, respectively. The microstructure of Ti-20Zr-XCr specimens showed significant difference by the concentration changes of Cr content showing acicular crystalline structure for Ti-20Zr-2Cr and Ti-20Zr-5Cr, and equiaxed crystalline structure for Ti-20Zr-10Cr and Ti-20Zr-15Cr. 2. Open-circuit potentials (E_(∝)) were rapidly decreased followed by steadiness as time elapse in all experimental groups except in Ti-20Z group. Ti-2OZr group showed an increase in E_(∝), from the first. 3. In potentiodynamic anodic polarization tests, all experimental groups showed more noble corrosion potential (E_(corr) than that of Ti-6Al-4V, and more basic E_(corr) than that of Ti. Especially, Ti-20Zr-10Cr alloy showed most favorable corrosion resistance among Ti-Zr-Cr alloys. 4. For Ti-20Zr-10Cr, Ti-20Zr-15Cr, and Ti-20Cr groups, which have more than 10% Cr content, the secondary corrosion potential shifted to noble direction in larger amounts than in the cases of control and other experimental groups. From these results, it was concluded that newly formulated Ti-20Zr-10Cr experimental alloy have adequate hardness and high corrosion resistance, and this alloy is promising candidate for a successful dental casting alloy.

치과 3D 프린팅용 자외선 경화 레진에 광원의 두 가지 파장에 따른 경화 및 항온수조 침적에 따른 변형률의 비교 분석

김동연,이광영,강후원,양천승,Kim, Dong-Yeon,Lee, Gwang-Young,Kang, Hoo-Won,Yang, Cheon-Seung 대한치과기공학회 2020 대한치과기공학회지 Vol.42 No.3

Purpose: This study aimed to analyze the shrinkage and expansion strain of ultraviolet (UV)-cured resin according to the wavelength of the light source and compare the shrinkage and expansion. Methods: We prepared the mold with according to the ISO 4049 specimen. The size of the circle in the mold was prepared with a height of 6.02 mm and a diameter of 4 mm. UV-curable resin for three-dimensional (3D) printing was injected into the circular mold. The control group was irradiated with a wavelength of 400~405 nm using UV-curing equipment (400 group), and the experimental group was irradiated with a wavelength of 460~465 nm (460 group). Both groups were produced ten specimens. The produced specimen was first measured with a digital micrometer. After the first measurement, the specimen was immersed in a constant temperature water bath for 15 days, after which the second measurement was performed, and the third measurement was taken after 30 days. The measured values were analyzed using the independent sample t-test (α=0.05). Results: In the non-immersion water tank, the contraction was 0.9% in the 400 group and 1.3% in the 460 group. In the constant temperature bath, the expansion was high at -0.4% in the 400 group for 15 days, and the smallest expansion was -0.03% for the 400 group for 30 days. There were significant differences between the two groups (p<0.05). Conclusion: The 400 group had a lower UV resin specimen strain than the 460 group. Therefore, it is recommended to use the wavelength required by the UV-curing resin.

다양한 중합 방법으로 제작한 간접 수복물용 복합레진의 굴곡 강도

김동연,박진영,강후원,김지환,김웅철,Kim, Dong-Yeon,Park, Jin-Young,Kang, Hoo-Won,Kim, Ji-Hwan,Kim, Woong-Chul 대한치과기공학회 2018 대한치과기공학회지 Vol.40 No.2

Purpose: The aim of this study is to evaluate composite resins of indirect restorations for testing of flexural strength according to various polymerization methods. Methods: Specimen was produced a total of 40 to 10 per each group with a length 25 mm, width 2 mm, thickness 2 mm using a Teflon zig. The polymerization groups were classified into four groups. The first group proceeded with light curing only(LC group). The second group proceeded with light and heat curing(LHC group). The third group proceeded with air press and light curing(ALC group). The fourth group proceeded with air press, light and heat curing(ALHC group). Each prepared group was evaluated by flexural strength test. Statistical analysis was performed by one-way ANOVA. Post-test was performed with Tukey test. Results: The lowest in the ALC group was 119.18 MPa and the highest in the ALHC group was 168.15 MPa. There were statistically significant differences. Conclusion : The composite resin of the indirect restoration is recommended to heat curing along with the air press.