• Title/Summary/Keyword: 순 티타늄

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Evaluation of plastic flow curve of pure titanium sheet using hydraulic bulge test (유압벌지실험을 이용한 순 티탄늄 판재의 소성유동곡선 평가(제2보))

  • Kim, Young-Suk;Kim, Jin-Jae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.4
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    • pp.718-725
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    • 2016
  • In this study, the plastic flow curve of commercially pure titanium sheet (CP Ti) actively used in the plate heat exchanger etc., was evaluated. The plastic flow curve known as hardening curve is a key factor needed in conducting finite element analyses (FEA) for the forming process of a sheet material. A hydraulic bulge test was performed on the CP Ti sheet and the strain in this test was measured using the DIC method and ARAMIS system. The measured true stress-true strain curve from the hydraulic bulge test (HBT) was compared with that from the tensile test. The measured true stress-true strain curve from the hydraulic bulge test showed stable plastic flow curve over the strain range of 0.7 which cannot be obtained in the case of the uniaxial tensile test. The measured true stress-true strain curve from the hydraulic bulge test can be fitted well by the hardening equation known as the Kim-Tuan model.

Weldability of Pure Titanium Thin plate for LPG Re-Condenser by Nd:YAG Laser - Physical Constant and Welding Parameter - (LPG 재응축기용 순티타늄 박판의 Nd:YAG 레이저 용접성(I) - 순티타늄의 물성과 용접변수 -)

  • Kim, Jong-Do;Gwak, Myeong-Seop;Lee, Chang-Je;Kim, Chang-Su
    • Proceedings of the KWS Conference
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    • pp.363-365
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    • 2007
  • Titanium and its alloys have excellent corrosion resistance, high strength to weight ratios and high temperature creep properties, which make them using many various fields of application. Responding to these needs, welding processes for titanium are also being used including TIG, MIG, resistance welding, plasma arc welding, diffusion welding, electron beam welding and laser welding. In this study, It is possible to get sound beads without humping bead and spatter with the decrease of peak power according to increase of pulse width and change of welding speed for heat input control at pulsed Nd:YAG laser welding of titanium plates for Lap welding.

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Lab Weldability of Pure Titanium by Nd:YAG Laser (Nd:YAG 레이저를 이용한 순티타늄판의 겹치기 용접성)

  • Kim, Jong-Do;Kwak, Myung-Sub
    • Journal of Advanced Marine Engineering and Technology
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    • v.32 no.2
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    • pp.315-322
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    • 2008
  • Titanium and its alloys have excellent corrosion resistance, high strength to weight ratios and creep properties in high temperature, which make them using many various fields of application. Especially, pure titanium, which has outstanding resistance for the stress corrosion cracking, crevice corrosion, pitting and microbiologically influenced corrosion, brings out to the best material for the heat exchanger, ballast tank, desalination facilities, and so on. Responding to these needs, welding processes for titanium are also being used GTAW, GMAW, PAW, EBW, LBW, resistance welding and diffusion bonding, etc. However, titanium is very active and highly susceptible to embrittlement by oxygen, nitrogen, hydrogen and carbon at high temperature, so it needs to shield the weld metal from the air and these gases during welding by non-active gas. In this study, it was possible to get sound beads without humping and spatter with a decrease of peak power according to increase of pulse width, change of welding speed and overlap rate for heat input control, and shield conditions at pulsed laser welding of titanium plates for Lap welding.

Comparison of histologic observation and insertional and removal torque values between titanium grade 2 and 4 microimplants (Grade 2, 4 티타늄 마이크로 임플랜트의 식립 및 제거 토크와 식립 후 조직학적 반응의 비교)

  • Kang, Sung-Taek;Sung, Jae-Hyun;Kyung, Hee-Moon;Park, Hyo-Sang;Kwon, Oh-Won
    • The korean journal of orthodontics
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    • v.36 no.3
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    • pp.171-177
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    • 2006
  • The purpose of this study was to evaluate the light microscopic features and the maximum insertional and removal torque value of microimplants, made from titanium grade 2 or 4, in the tibia of 6 rabbits. First, the maximum torque values of microimplants at implantation were measured. After 2, 8, and 12 weeks of healing time, the microimplant-containing segments of tibia of 2 rabbits were removed and the maximum removal torque of each microimplant were measured. Comparisons of histologic examination and insertional and removal torque values were carried out for the two groups of microimplants. Removal torque values were significantly increased in both groups after 8 and 12 weeks as compared to 2 weeks after implantation. Other values measured did not show any statistically significant differences and there were no histological differences between grade 2 and 4 titanium. Based on these results, this study showed that there were no significant differences between grade 2 and 4 titanium. It seems better to use grade 4 titanium for making microimplants because grade 4 titanium is mechanically harder than grade 2 titanium and has similar retention.

Development of Manufacturing Process of Pure Titanium Wire to make Eyewear Frame (안경용 순티타늄 wire 제조 공정개발)

  • Choi, Gye-Hun;Kim, Sang-Yeoun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.3
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    • pp.1105-1110
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    • 2011
  • After pure titanium Ingot(G2) with 400mm in diameter was manufactured, the analysis of its ingredients showed that the oxygen content was 0.073wt% and the iron content was 0.03wt%, which made ASTM Gr.2 standardization satisfactory. The processed titanium ingot produced 42mm wire rod, and hot rolling of 18th phase produced 9mm wire rod. The hardness analysis of 15.8mm wire rod, which was processed in hot rolling of 10th phase from the surface to the center, resulted in almost constant value with Hv150~200. The last 9mm wire rod had a different yield strength and elongation percentage depending on the temperature as it was led in to a hot roller. However, tensile strength revealed an approximate value and made ASTM B863 standardization satisfactory.

Evaluation of press formability of pure titanium sheet (순 티탄늄 판재의 프레스 성형성 평가(제 1보))

  • Kim, Young-Suk;In, Jeong-Hun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.3
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    • pp.380-388
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    • 2016
  • Commercially pure titanium (CP Ti) has been actively used in plate heat exchangers due to its light weight, high specific strength, and excellent corrosion resistance. However, compared with automotive steels and aluminum alloys, there has not been much research on the plastic deformation characteristics and press formability of CP Ti sheet. In this study, the mechanical properties of CP Ti sheet are clarified in relation to press formability, including anisotropic properties and the stress-strain relation. The flow curve of the true stress-true strain relation is fitted well by the Kim-Tuan hardening equation rather than the Voce and Swift models. The forming limit curve (FLC) of CP Ti sheet was experimentally evaluated as a criterion for press formability by punch stretching tests. Analytical predictions were also made via Hora's modified maximum force criterion. The predicted FLC with the Kim-Tuan hardening model and an appropriate yield function shows good correlation with the experimental results of the punch stretching test.

Weldability with Process Parameters During Fiber Laser Welding of a Titanium Plate (II) - The Effect of Control of Heat Input on Weldability - (티타늄 판재의 파이버 레이저 용접시 공정변수에 따른 용접특성 (II) - 입열량 제어에 따른 영향 -)

  • Kim, Jong Do;Kim, Ji Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.12
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    • pp.1055-1060
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    • 2016
  • Laser welding is a high-density energy welding method. Hence, deep penetration and high welding speed can be realized with lower heat input as compared with conventional welding. The heat input of a CW laser welding is determined by laser power and welding speed. In this study, bead and lap welding of $0.5mm^t$ pure titanium was performed using a fiber laser. Its weldability with laser power and welding speed was evaluated. Penetration, bead width, joining length, and bead shape were investigated, and the mechanical properties were examined through tensile-shear strength tests. Welds with sound joining length were obtained when the laser power and welding speed were respectively 0.5 kW and 2.5 m/min, and 1.5 kW and 6 m/min, and the weld obtained at low output presented better ductility than that obtained at high output.

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.