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타이타늄 레이저용접의 연구동향 및 이종겹치기 고속도 레이저용접 특성
이수진(Su-Jin Lee),천은준(Eunjoon Chun),서정(Jeong SUH) 대한용접·접합학회 2017 대한용접·접합학회지 Vol.35 No.4
As the use of titanium in various industrial sectors has gained attention, interest in basic properties of titanium, alloy technology, processing technology and applications is increasing. Titanium has been developed for the purpose of aerospace and military use and has been called “the material of dreams”, but now its use is expanding in various fields such as implants, sports equipment, accessories, frames, automobiles, medical devices and heat exchangers. Titanium is abundant in the Earth"s crust, but it is not found as the pure titanium metal state because of its strong binding force with oxygen. Therefore, in order to use it as a metal, it has to undergo a manufacturing process such as reduction treatment, so it belongs to relatively expensive materials such as 15 times of aluminum and 8 times of stainless steel per unit weight. Therefore, a research and development of processing methods of titanium and its alloys have been actively carried out, among which welding of titanium materials is a necessary technique for various application and flexible application of Titanium materials. In this paper, especially, laser welding method is discussed as a processing method which can improve the product quality and reduce the cost of the Titanium products.
Cheolho Park,Namhyun Kang,Stephen Liu,Juseung Lee,Eunjoon Chun,Sun‑Joon Yoo 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.3
Hydrogen can provide pure and clean energy; however, to use it as an energy source, facilities such as hydrogen carriersand recharging stations need to be constructed. Structural steels are affected by hydrogen embrittlement (HE), and theirsusceptibility to this needs to be investigated prior to their use in construction. Most structural steels are normally fabricatedusing thermomechanical controlled processing, which produces a large dislocation density to increase strength. This studyinvestigated the prestrain effect on HE susceptibility of EH 36 steels using thermal desorption spectroscopy (TDS) andin situ slow-strain-rate testing. Hydrogen was electrochemically charged into specimens, and the reversible hydrogen contentand that relating to trap sites were measured using TDS. With an increase in prestrain, there was increase in the diffusiblehydrogen content; furthermore, with hydrogen charging, there was a drastic reduction in total elongation with an increasein prestrain. In addition, there was an increase in HE susceptibility with an increase in prestrain compared to when an aircondition was employed. Specifically, there was an abrupt increase in HE sensitivity at a prestrain value between 10 and15%; strain hardening was more dominant below a prestrain value of 10%; and HE was more dominant above a prestrainvalue of 15% for EH 36 steels.