• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.547-550
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• 2008

Precipitation characteristics of the Fe-36Ni based high strength Invar alloy for power transmission wire was investigated in this study. High strength can be obtained in this alloy through precipitation hardening and strain hardening by cold working. $FactSage{(R)}$ in this study, revealing that equilibrium phases which can be formed are two kind of MC-type precipitates and MoC carbide. The latter stoichiometric carbide was expected to be formed at relatively lower temperature $770^{\circ}C$. High strength above 1000MPa and 40% of elongation were obtained at room temperature in both cases.

• 치위생과학회지
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• 제9권4호
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• pp.405-412
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• 2009

본 연구는 도재소부용 비귀금속에 Au 코팅 층을 형성하고, Au 코팅 층이 금속-도재의 결합력에 미치는 영향을 알아보고자 2출 굴곡 시험 후에 SEM/EDS 방법으로 조사하여 비교하였다. 1. Ni-Cr ally 군과 Co-Cr alloy 군, 그리고 Ti 군의 절단면 시편의 전자현미경 사진에서 Au 코팅 층은 산화층의 확산을 제어하는 것으로 관찰되었다. 2. 2축 굴곡 시험 후에 EDS 분석 결과 Ni-Cr alloy 군과 Co-Cr alloy 군에서 Si 함량은 Au 코팅 층을 형성한 시편에서 약간 감소하였고, 결합실패의 형태는 cohesive failure와 adhesive failure가 혼재된 양상으로 관찰되었다. 3. Ni-Cr alloy 군과 Co-Cr alloy 군에서 Au 코팅 층은 도재-금속 결합력에 미치는 영향은 미미하였다. 4. Ti 군의 결합실패 형태는 Ni-Cr alloy 군과 Co-Cr alloy 군에 비해서 adhesive failure 양상이 두드러지게 관찰되었고, Au 코팅 층은 도재-금속 결합력에 영향을 미치지 않았다. 이상의 결과 비귀금속에 적용한 Au 코팅은 산화층의 확산을 제어 하는 것으로 관찰 되었으나, 금속-도재 간의 결합력 증징에 미치는 효과는 미미하였다. Au 코팅을 이용하여 금속-도재 간의 결합력 증진을 위해서는 많은 연구가 지속되어야 할 것으로 사료된다.

• 한국생산제조학회지
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• 제26권4호
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• pp.357-364
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• 2017

Metal casting is a process in which molten metal or liquid metal is poured into a mold made of sand, metal, or ceramic. The mold contains a cavity of the desired shape to form geometrically complex parts. The casting process is used to create complex shapes that are difficult to make using conventional manufacturing practices. For the optimal casting process design of sleeve parts, various analyses were performed in this study using commercial finite element analysis software. The simulation was focused on the behaviors of molten metal during the mold filling and solidification stages for the precision and sand casting products. This study developed high-life sleeve parts for the sink roll of continuous hot-dip galvanizing equipment by applying a wear-resistant alloy casting process.

• Journal of Welding and Joining
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• 제17권5호
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• pp.89-96
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• 1999

The base metal and weld metal of alloy designed austenitic stainless steels were electrochemically tested in artificial sea water. Pitting resistance of 14 different stainless steels was evaluated by measuring pitting potential. The effect of alloy element to pitting potential was evaluated by changing chromium, nickel, sulfur content. The site of pitting initiation was observed by optical microscope. As a result of electrochemical test, pitting resistance of weld metal was higher than base metal, and rapidly cooled weld metal has higher pitting potential than slowly cooled weld metal. In case of primary δ-ferrite solidification, pitting potential was increased, but residual δ-ferrite was detrimental to pitting resistance. Chromium was more effective to pitting resistance than nickel, and sulfur was very detrimental element to pitting resistance.

• 한국주조공학회지
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• 제33권3호
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• pp.122-126
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• 2013

Recently, heat-resistant aluminum alloy has been re-focused as a downsizing materials for the internal combustion engines. Heat-resistant Al alloy development and many researches are still ongoing for the purpose of improving thermal stability, high-temperature mechanical strength and fatigue properties. The conventional principle of heat-resistant Al alloy is the precipitation of intermetallic compounds by adding a variety of elements is generally used to improve the mechanical properties of Al alloys. Heat resistant aluminum alloys have been produced by CrW homogeneous solid solution to overcome the limit of conventional heat resistant aluminum alloy. From EPMA, it is found that CrW homogeneous soild solution phases with the size of $50-100{\mu}m$ have been dispersed uniformly, and there is no reaction between aluminum and CrW alloy. In addition, after maintaining at high temperature of 573 K, there is no growth of hardening phase, nor desolved, but CrW still exists as a homogeneous solid solution.

• 한국산업융합학회 논문집
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• 제22권2호
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• pp.105-110
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• 2019

Most titanium alloy waste with cutting oil was discarded without recycling process so that it can be caused by metal and oil fires. However, there is no fire management system and studies on the titanium or titanium alloy waste in spite of high fire risk. The purpose of this experimental study is to identify the fire risk of the titanium alloy waste with cutting oil. We collected the 120g waste which was made in the biomedical titanium alloy cutting process. The waste was burned and conducted thermal image analysis with infrared camera. The experimental results which illustrated the process, characteristics, and trends of fire are presented. Firstly, the cutting oil was burned and partially the titanium alloy waste was burned. The maximum temperature of the fire was more than $650^{\circ}C$ in some specific spots. These results means when a lot of titanium alloy waste with cutting oil was ignited, this fire could connect the titanium fire. In other words, the fire has a flammable liquid fire and combustible metal fire at the same time. The experimental study could be used fire prevention, response, and investigation of the titanium alloy waste.

• 대한치과보철학회지
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• 제18권1호
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• pp.87-97
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• 1980

To compare the castability of various alloys popularly used in Korea for porcelain-fused-to-metal restorations, author selected Degudent G as precious alloy, J.P. 92 as semiprecious alloy and Vera Bond, Rexillium III, Unit Bond, Fine Bond as non precious alloys. With nylon lines and gauge waxes, author made the wax patterns for the castability comparison test. In the same conditions, wax patterns were invested, burned out and cast. Author obtained the following results from this study. 1. The castability of Degudent G as precious alloy for porcelain-fused-to-metal crown and bridge was the best of all. 2. The castability of nonprecious alloys was less than Degudent G as precious alloy, but their differences were not large. 3. The castability of Rexillium III is the best of all nonprecious alloys and that of Vera Bond, Unit Bond had nearly the same results. 4. Semiprecious alloy (J.P. 92) was less castable than nonprecious alloys.

• 대한치과기공학회지
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• 제31권3호
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• pp.27-34
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• 2009

This study compared and analyzed changes to the mechanical characteristics to nonprecious metal alloy for porcelain fused to metal crowns when it's repetitively used without the addition of new alloy. Metal samples were made with the Verabond V nonprecious metal alloy. Those samples to measure tensile and yield strength were made in the standardized design(ISO 22674), those to measure bond strength in the $25mm{\times}3mm{\times}0.5mm$ format, and those to measure hardness in the $10mm{\times}10mm{\times}1mm$ format. A ceramic to measure bond strength was made at the center of the metal sample in the length of $8{\ss}{\AE}$ by using Noritaker Super Porcelain EX-3. Ten samples were prepared for one, three and five repetitions of casting each. The test results were as follows: 1. The more casting was repeated, the more significantly tensile strength dropped. 2. The more casting was repeated, the more significantly yield strength dropped. 3. Repetitive casting didn't cause significant changes to bond strength. 4. The Vickers hardness significantly fell with increasing repetitions of casting. There were no changes to bond strength observed with the increasing number of repeating casting. But tensile strength, yield strength, and Vickers hardness decreased. Those results indicate that repeated casting can affect durability and that careful attention should be paid by avoiding repetitive use or excessive increase of uses when no new alloy is added.

• 한국추진공학회지
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• 제7권4호
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• pp.73-79
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• 2003

재생 냉각형 액체 로켓엔진 제작에 주로 사용되는 합금에 대하여 브레이징 접합 강도 시험 및 파단면 분석을 실시하였다. 브레이징 시 사용되는 용가재(Filler Metal)로 니켈을 주성분으로 하는 BNi-2, BNi-7를 사용하였다. 5종의 합금에 대하여 모두 12개의 시편을 제작하여 인장 강도 시험 및 금속현미경을 통한 접합면 분석을 통해 재료 및 용가재 특성을 분석하였다. 크롬동과 타 합금과의 접합 강도가 크롬/지르코늄동과 타 합금과의 접합 강도보다 높게 나왔다. BNi-2가 BNi-7보다 모재에 대한 젖음성이 보다 더 우수하여 접합면 인장 강도가 BNi-2로 사용한 경우가 BNi-7을 사용한 경우보다 더 높게 나왔다.

• 대한치과기공학회지
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• 제35권1호
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• pp.1-17
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• 2013

Purpose: This study was to assess the extents of the release of metals from the non-precious alloys used for dental casting by measuring the differences in the extents of the release of metals by types of alloys, pH level and elapsed time. Methods: Uniform-sized specimens(10 each) were prepared according to the Medical Device Standard of the Korea Food and Drug Administration(2010) and International Standard Organization(ISO22674, 2006), using four types of alloys(one type of Ni-Cr and one type of Co-Cr used for fixed prosthesis, and one type of Ni-Cr and one type of Co-Cr used for removable prosthesis). A total of 12 metal-release tests were performed at one-day, three-day, and two-week intervals, for up to 20 weeks. The metal ions were quantified using an Inductively Coupled Plasma-Atomic Emission Spectrometer. Results: The results showed that the extent of corrosion was higher in the ascending order of Jdium-$100^{(R)}$, Bellabond-$Plus^{(R)}$, Starloy-$C^{(R)}$, and Biosil-$F^{(R)}$. The lower the pH and the longer the elapsed time were, the greater the increase in metal corrosion. At pH 2.4, the release of Ni from Jdium-$100^{(R)}$, a Ni-Cr alloy, was up to 15 times greater than the release of Co from the Co-Cr alloy from two weeks over time, indicating that the Ni-Cr alloy is more susceptible to corrosion than the Co-Cr alloy. Conclusion: It is recommended that Co-Cr alloy, which is highly resistant to corrosion, be used for making dental prosthesis with a non-precious alloy for dental casting, and that non-precious alloy prosthesis be designed in such a way as to minimize the area of its oral exposure. For patients with non-precious alloy prostheses, a test of the presence or absence of periodontal tissue inflammation or allergic reaction around the prosthesis should be performed via regular examination, and education on the good management of the prosthesis is needed.