• Title/Summary/Keyword: Pure Titanium

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A Study on Plastic Deformation Characteristics and Formability for Pure Titanium Sheet (순 티타늄 판재의 변형 특성 및 성형성 평가)

  • In, J.H.;Jeong, K.C.;Lee, H.S.;Kim, J.H.;Kim, J.J.;Kim, Young Su
    • Transactions of Materials Processing
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    • v.27 no.5
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    • pp.301-313
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    • 2018
  • In this paper, tensile test was performed on pure titanium sheet (CP Ti sheet) with HCP structure in each direction to evaluate mechanical and surface properties and analyze microstructural changes during plastic deformation. We also evaluated forming limits of Ti direction in dome-type punch stretching test using a non-contact three-dimensional optical measurement system. As a result, it was revealed the pure titanium sheet has strong anisotropic property in yield stress, stress-strain curve and anisotropy coefficient according to direction. It was revealed that twinning occurred when the pure titanium sheet was plastic deformed, and tendency depends differently on direction and deformation mode. Moreover, this seems to affect the physical properties and deformation of the material. In addition, it was revealed the pure titanium sheet had different surface roughness changes in 0 degree direction and 90 degree direction due to large difference of anisotropy, and this affects the forming limit. It was revealed the forming limit of each direction obtained through the punch stretching test gave higher value in 90 degree direction compared with forming limit in 0 degree direction.

Microstructures and Mechanical Properties of Pure Titanium Casting Specimens with Mold Temperatures (순수 티타늄 주조체의 주형온도에 따른 미세조직 및 기계적 성질)

  • Cha, Sung-Soo;Nam, Sang-Yong;Song, Young-Ju
    • Journal of Technologic Dentistry
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    • v.32 no.4
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    • pp.307-315
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    • 2010
  • Purpose: The purpose of this study was to investigate the change of microstructures and mechanical properties of pure titanium casting specimens as a function of mold temperatures. Methods: The pure titanium castings were fabricated using the centrifugal vacuum casting method with different mold temperatures of $200{\sim}500^{\circ}C$. The resulting castings were characterized by optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and vicker,s hardness tester. Results: In case of the mold temperatures over $400^{\circ}C$, the porosity, surface crack and large grain size were observed in resulting castings. Conclusion: In this work, The most suitable mold temperature in casting of pure titanium was $300^{\circ}C$.

Attachment of Human Gingival Fibroblasts to Commercially Pure Titanium Surfaces with Different Instruments;A comparative Study in Vitro (기구조작에 따른 순수 타이타늄 표면 변화와 치은 섬유아 세포 부착에 관한 연구)

  • Seo, Sung-Chan;Song, In-Taeck;Lim, Jeong-Su;Kim, Hyung-Seop
    • Journal of Periodontal and Implant Science
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    • v.29 no.3
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    • pp.607-621
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    • 1999
  • This study examined the human fibroblasts cell attachment to commercially pure titanium surface which had been instrumented by 3 types of periodontal instruments. Commercially pure titanium plates were uniformly scaled using plastic, stainless steel, titanium curette. these all experimental groups 65 undirectional strokes with the designated curettes. Alteration of the surfaces due to instrumentation was evaluated by Form Talysurf(R) and reported as Ra value(mean surface roughness). Then other experimental groups were immersed in a cell suspension of human gingival fibroblasts($1{\times}10^5$ cell/ml). After 3 days of culture, cell attachment and morphology was observed by SEM, and attached cell were counted by Hemocytometer. A significant difference in mean Ra value was observed for surface instrumented by metal curette compared to either control surface or surface instrumented by the plastic curette(P<0.01). No stastically significant difference was noted between control surface and those instrumented by the plastic curette. SEM observation showed that cell morphology and attachment to the commercially pure titanium plate was similar appearance on the all experimental groups. Experimental groups instrumented by titanium curette and stainless steel curette were more attached cell number than control group, but experimental group instrumented by plastic curette were similar with control groups(P<0.01). In summary, metal curette produced an significant alteration of the commercially pure titanium surface and more favorable surface topography for cell attachment. Otherwise plastic curette was insignificantly altered the commercially pure titanium surface(P<0.01).

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A Study of Weldability for Pure Titanium by Nd:YAG Laser(I) - Weld Properties with Shield Conditions - (순티타늄판의 Nd:YAG 레이저 용접성에 관한 연구(I) - 실드 조건에 따른 용접특성 -)

  • Kim, Jong-Do;Kwak, Myung-Sub;Kim, Chang-Soo
    • Journal of Welding and Joining
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    • v.27 no.5
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    • pp.55-61
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    • 2009
  • Pure titanium and its alloys have good formability, excellent corrosion resistance and high strength to weight ratios. Therefore, it has been using to heat exchangers, offshore plants, sports equipments, and etc. As broad as its application fields, it also increases welding locations. Conventional GTAW and GMAW are very popular welding methods of titanium, but it has a high heat input and wide HAZ. It has a possibility of inducing Stress Corrosion Cracking. So, laser welding method has been using to get reliable welds by reducing heat input. Weld beads change its color to silver, gold, brown, blue, and gray by shied conditions. And the closer to gray, the more oxidize, nitride and embrittlement. The most effective atom to embrittlement was nitrogen. And shield gas flow was not so effective over the constant flow rates. In this study, weld properties of the pure titanium were investigated by pulsed & CW Nd:YAG lasers and evaluated by various shield conditions. And It is observed that nitrogen is more effective to oxidation and embrittlement of titanium compared with oxygen by oxygen and nitrogen quantitative analysis.

A Study of Weldability for Pure Titanium by Nd:YAG Laser(II) - Welding Properties of Butt Welding - (순티타늄판의 Nd:YAG 레이저 용접성에 관한 연구(II) - 맞대기 용접 특성 -)

  • Kim, Jong-Do;Kwak, Myung-Sub;Song, Moo-Keun;Park, Seung-Ha
    • Journal of Welding and Joining
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    • v.27 no.6
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    • pp.68-73
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    • 2009
  • Recently, as titanium and titanium alloys are being increasingly used in wide areas, there are on-going researches to obtain high quality weld zone. In particular, growing interest is being drawn to laser welding, which involves low heat input and large aspect ratio in various welding processes and can facilitate shield in atmospheric condition compared with electron beam welding. The first report covered the analysis of embrittlement by the bead color of weld zone through quantitative analysis of oxygen and nitrogen and measurement of hardness as basic experiment to apply laser welding to titanium. Results indicated that the element that affect embrittlement the most was nitrogen, and as embrittlement and oxygenation go on, bead color changed to silver, gold, brown, blue and gray. This study performed butt welding of pure titanium and STS304 by using 1kW CW Nd:YAG laser, and to find out basic physical properties, evaluated welding performance by laser output, welding speed, root gap and misalignment etc, and examined mechanical properties through tensile stress and Erichsen test. The reason particles of pure titanium welded metal and HAZ are greater than STS304 is because they are pure metal and do not include many impure elements that work as nuclei in case of resolidification, thus becoming coarse columnar crystals eventually. In addition, the reason STS304 requires more energy during welding than pure titanium is because the particle size of base metal is smaller.

The Study for Improving the Weldability of Pure Titanium Sheet by Using Fiber Laser - The Effect of Shielding Gas Nozzle Variable - (파이버 레이저를 이용한 순 티타늄 박판의 용접특성 향상을 위한 연구 - 실드가스 노즐변수의 영향 -)

  • Kim, Jong-Do;Kim, Ji-Sung
    • Journal of Welding and Joining
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    • v.34 no.5
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    • pp.6-12
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    • 2016
  • This study was performed bead welding of pure titanium by using fiber laser. Since titanium is very sensitive to oxidation and nitriding during welding, it is important to compose the shielding equipment compared with different material. Thus side and coaxial shield nozzle, rail and chamber type shielding equipment are widely used to protect effectively the weld during welding. Experiments were performed by changing nozzle angle and distance using side and coaxial shield nozzle. The bead colors of gold, brown, blue, purple and yellowish white were obtained by changing variables of shield nozzle, and then its weldability was investigated. As experiment result, sound and not brominated beads were formed when side nozzle angle and distance were respectively $45^{\circ}$ and 10 mm.

A Study on the Residual Stress Distribution of Pure Titanium Welding Material (순수티타늄 용접재의 잔류응력분포에 관한 연구)

  • 최병기;권택용
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.70-75
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    • 2002
  • It is generally applied constraint welding condition to structure manufacture in the industry field. But it is thinkable that the residual stress of the construction and specimens for experiment is different because not constraint welding but non-constraint welding are applied for experiment. To apply the constraint welding condition as the industry field and compare and evaluate the welding residual stress distribution, the TlG welding of the pure titanium was carried out under constraint and non-constraint welding conditions

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The Effects of Citric Acid on HA coated Implant Surface (구연산 HA임플란트 표면구조에 미치는 영향)

  • Kim, Joong-Cheon;Kwon, Young-Hyuk;Park, Joon-Bong;Herr, Yeek;Chung, Jong-Hyuk;Shin, Seung-II
    • Journal of Periodontal and Implant Science
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    • v.37 no.3
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    • pp.575-584
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    • 2007
  • The present study was performed to evaluate the effect of citric acid on the change of implant surface microstructure according to application time. Implants with pure titanium machined surface, and HA coated surface were utilized. Pure titanium machined surface and HA coated surface were rubbed with pH 1 citric acid for 30s., 45s., 60s., 90s., and 120s. respectively. Then, the specimens were processed for scanning electron microscopic observation. The following results were obtained. 1. The specimens showed a few shallow grooves and ridges in pure titanium machined surface implants. The roughness of surfaces conditioned with pH 1 citric acid was slightly increased. 2. In HA-coated surfaces, round particles were deposited irregularly. The specimens were not significant differences within 45s. But, began to be changed from 60s. The roughness of surfaces was lessened and the surface dissolution was increased relative to the application time. In conclusion, pure titanium machined surface implants and HA coated surface implants can be treated with pH 1 citric acid for peri-implantitis treatment if the detoxification of these surfaces could be evaluated.

Effect of Application of Tetracycline - HCl on Implant Surface;Scanning Electron Microscopic Study (염산테트라싸이클린이 임플란트 표면에 미치는 효과;주사전자현미경적 연구)

  • Hong, Jung-Ah;Herr, Yeek;Lee, Man-Sup;Park, Joon-Bong
    • Journal of Periodontal and Implant Science
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    • v.31 no.2
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    • pp.333-344
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    • 2001
  • The present study was performed to evaluate the effect of tetracycline - HCl on the change of implant surface microstructure according to application time. Implants with pure titanium machined surface and titanium plasma-sprayed surface were utilized. Implant surface was rubbed with 50mg/ml tetracycline - HCl solution for 1 min., $1\frac{1}{2}\;min$., 2 min., $2\frac{1}{2}\;min$. and 3min. respectively in the test group and with saline for 1 min. in the control group. Then, the specimens were processed for scanning electron microscopic observation. The following results were obtained. 1. Pure titanium machined surfaces conditioned with saline for 1 min., showed a few shallow grooves and ridges and were less irregular. 2. Pure titanium machined surfaces conditioned with 50mg/ml tetracycline - HCl solution showed more irregular and corrosive surfaces compared to the control group irrespective of the application time of tetracycline - HCl solution. 3. Titanium plasma-sprayed surfaces conditioned with saline for 1 min., were deposited with round amorphous particles and showed round or irregular pores that can be connected to each other. 4. The irregularity of titanium plasma-sprayed surfaces conditioned with 50mg/ml tetracycline - HCl solution was lessened and the flattened areas were wider relative to the application time of tetracycline - HCl solution. 5. Titanium plasma-sprayed surfaces conditioned with tetracycline - HCl solution for 1 min. and $1\frac{1}{2}\;min$. were very similar to that of the control group, but the surfaces conditioned for 2 min., $2\frac{1}{2}\; min$. and 3 min. were changed. In conclusion, pure titanium machined surfaces were changed irrespective of the application time of tetracycline - HCl solution. And titanium plasma-sprayed surfaces conditioned with tetracycline - HCl solution began to be changed from $1\frac{1}{2}\;min$. This results will be applicable to the regenerative procedures for peri-implantitis treatment.

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Acoustical Anisotropy Evaluation of Pure Titanium plate Using Neural Network (신경회로망을 이용한 순 티타늄판재의 음향이방성 평가)

  • Park, Hee-Dong;Yun, In-Sik;Yi, Won
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.9
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    • pp.1103-1109
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    • 2011
  • This research quantitatively confirmed an acoustical anisotropy that exists in a pure titanium plate from the signal of ultrasonic flow detection and suggested a new way to evaluate the acoustical anisotropy by inputting acquired characteristic of ultrasound signal into the neutral network. Using the fact with the suggested method that the characteristic of ultrasound signal is shown differently depending on the pure titanium plate's rolling direction, the neural network was constructed by extracting the characteristic that can decide each direction of $0^{\circ}$, $45^{\circ}$, and $90^{\circ}$ with waveform analysis program. As a result of inputting the characteristic of ultrasound signal acquired from a random rolling direction into the neural network that was built like this, it showed a pattern recognition rate higher than 95% on directions of $0^{\circ}$, $45^{\circ}$, $90^{\circ}$.