• 소성∙가공
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• 제11권5호
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• pp.388-393
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• 2002

Heat-treatment-free steels have been replacing for conventional quenched-and-tempered structural steels since the microalloyed forging steel was developed in early 1970s in Germany. Substantial cost reduction provides the driving force for this change. As a result of intensive R & D efforts and application trials, various kinds of grades, for example heat-treatment-free steels for hot forging, machining and cold heading, have been developed and moreover these steels are in tonnage production throughout the world. The developments in alloy steels, processing conditions and structure-property characteristics of the heat-treatment-free steels, are described and also recent trend and future prospect are summarized in this report.

• Journal of Welding and Joining
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• 제4권2호
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• pp.21-29
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• 1986

The influence of welding heat input variation(600-900J/cm) and heat-treatment condition after welding on tensile strength of butt welded joint in $175Kg/mm^2$ strength level Maraging steel(Co-free and Co-containing) sheets was investigated on the basis of hardness distribution, microstructure of weld metal and fracture surface. The obtained main results are as follows; 1. The strength of weldment (UTS, NTS), joint efficiency showed a little decreasing tendency with the increase in welding heat input, and the elongation showed a little increasing tendency with the increase in the width of weld metal. It was considered because of the plastic constraint of the high strength base metal. 2. The strength of weldment was better in the solution treatment and aging than the aging only after welding due to the disappearance of almost denverite in weld metal. 3. The hardness distribution in weldment after welding and heat-treatment was almost similar to both Co containing and Co free Maraging steel with change in welding heat input. 4. The fracture was occurred at weld metal, and the fracture surface showed a relatively shallow dimples in both Co containing and Co free Maraging steel.

• 열처리공학회지
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• 제20권4호
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• pp.181-186
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• 2007

Effect of heat treatment conditions on formability and property of warm hydroformed parts for Al 6061 extruded tubes was investigated in this study. For the investigation, as-extruded, fully annealed and T6-treated Al 6061 seamless tubes were prepared. To evaluate the warm hydroformability, uni-axial tensile test and free bulge test were performed at various pre- and post-heat treatment conditions. And the tensile test specimens were obtained from hexagonal prototype hydroformed parts at $250^{\circ}C$. As a result, hydroformability of fully annealed tube is 25% higher than that of extruded tube. The tensile strength and strain of hydroformed part reach to 330 MPa and 12%, respectively, when the part was T6 treated after warm hydroforming. However, the hydroformability of T6 pre-treated tube is relatively low due to the decreased elongation, 8%.

• 한국전기전자재료학회논문지
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• 제13권4호
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• pp.349-358
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• 2000

Fabrication and Characterization of Bi$_{2}$/Sr$_{2}$/CaCu$_{2}$/O$_{8}$(Bi2212) superconductor thick films were fabricated successfully on C tapes by liquid reaction between Cu-free precursors of Bi$_{x}$/SrCaO/$_{y}$(x=1.2-2) and Cu tapes. Cu-free Bi-Sr-Ca-O powder mixtures were screen-printed on Cu tapes and heat-treated at 850-87$0^{\circ}C$ for several minutes in air oxygen nitrogen and low oxygen pressure. In order to obtain the optimum heat-treatment condition we studied the effect of the precursor composition the printing thickness and the heat-treatment atmosphere on the superconducting properties of Bi2212 films and the reaction mechanism. Microstructures and phases of thick films were analyzed by films and the reaction mechanism. Microstructures and phases of thick films were analyzed by optical microscope and XRD. The electric properties of superonducting films were examined by the four probe method. At heat-treatment temperature the thick films were in a partially molten state by liquid reaction between CuO of the oxidized copper tape and the precursors which were printed on Cu tapes. During the heat-treatment procedure Bi2212 superconducting particle nucleate and grow in preferred orientations.ons.s.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.69-72
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• 1999

A Well oriented Bi$_2$re$_2$CaCu$_2$O$\sub$8/(Bi2212) superconductor thick films were formed successfully on a copper substrate by liquid reaction between a Cu-free precursor and Cu tape using method in which Cu-free BSCO powder mixture was printed on copper plate and heat-treated. And we examined the mechanism for the rapid formation of Bi2212 superconducting films from observing the surface microstructure with heat-treatment time. At heat-treatment temperature, the printing layer partially melt by reacting with CuO of the oxidizing copper plate, and the nonsuperconducting phases present in the melt are typically Bi-free phases and Cu-free phases. Following the partial melting, the Bi$_2$Sr$_2$CaCu$_2$O$\sub$8/ superconducting phase is formed at Bi-free phase/liquid interface by nucleation and grows. It was confirmed that the phase colony from the phase diagram of Bi$_2$O$_3$-(SrO+CaO)/2-CuO system is similar to the observed result.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2000년도 KIASC Conference 2000 / 2000년도 학술대회 논문집
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• pp.85-88
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• 2000

Cu-free Bi-Sr-Ca-O powder mixtures were screen-printed on Cu tapes and heat-treated at 850-$870^{\circ}C$ for several minutes in air, oxygen, nitrogen and low oxygen pressure. Cu-free precursors were composed of Bi_{x}$SrCaO_{y}$ (x=1.2-2). In order to obtain the optimum heat-treatment condition, we studied on an effect of the precursor composition, the printing thickness and the heat-treatment atmosphere on the superconducting properties of Bi2212 films and the reaction mechanism of their rapid formation. Microstructures and phases of thick films were analyzed by optical microscope and XRD. The electric properties of superconducting films were examined by the four probe method. At heat-treatment temperature, the thick films were in a partially molten state by liquid reaction between CuO in the oxidized copper tape and the precursors which were printed on Cu tapes.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.388-391
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• 1999

Well oriented Bi2212 superconductor thick films were formed successfully on a copper substrate by liquid reaction between a Cu-free precursor and Cu tape method in which Cu-free BSCO powder mixture was' printed on copper plate and heat-treated. And we examined the effect of heat-treatment atmosphere for the superconducting properties and microstructure of Bi2212. The composition of Cu-free BSCO powder mixture was Bi$_2O_3$ : SrCO$_3$ : CaCO$_3$ = 1.2~2 : 1 : 1 and the heat-treatment for the superconducting formation reaction was performed in air, oxygen, nitrogen and low oxygen pressure. At heat-treatment temperature, the printing layer partially melt by reacting with CuO of the oxidizing copper plate, and the nonsuperconducting phases present in the melt are typically Bi-free phases and Cu-free phases. Among the nonsuperconducting phases, it is known that the (Sr,Ca)CuO$_3$ phase restrain the formation of the Bi2212 superconducting phase. Because a kind of the nonsuperconducting phases is controled by the oxygen partial pressure, the optimum condition in which the remnants of the second phases don't leave in the fully processed conductor was determined by XRD and the critical tempera to re (Tc) analysis.

• 동아시아식생활학회지
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• 제23권1호
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• pp.92-97
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• 2013

This study was conducted to understand the quality characteristics of salt fermented anchovies with heat treatment by measuring their chemical compositions. The heat-treated and non-heat treated salt fermented anchovies contained, respectively, 63.21 and 66.51% of moisture, 2.24 and 2.12% of total nitrogen (TN), and 1,537 and 1,520 mg/100 g of amino nitrogen (AN). In addition, heat-treated and non-heat-treated salt fermented anchovies contained 127 and 134 mg/100 g of volatile basic nitrogen (VBN), respectively. Moreover, measured the microbial level of heat-treated and non-heat-treated salt fermented anchovies was $2.58{\times}10^4$ and $3.61{\times}10^2$ CFU/mL, respectively. Also, the heat-treated and non-heat-treated salt fermented anchovies 3.65 and 0.30 units of protease activities, respectively. The total free amino acid contents in heat-treated and non-heat-treated salt fermented anchovies was 4,964 and 6,638 mg/100 g, respectively. The major free amino acid were glutamic acid, leucine, lysine, alanine, valine, isoleucine. Our results provide the characteristics of salt fermented anchovies and encourage their application for the food industry and cooking.

• 한국식품영양과학회지
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• 제14권3호
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• pp.301-304
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• 1985

녹차의 맛을 내는데 주요 성분인 유리아미노산과 유리당을 HPLC로 분석한 결과를 요약하면 다음과 같다. 1. 16종의 유리아미노산이 검출되었다. 즉, aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, histidine, lysine, arginine이 그것이었다. 2. 증제차가 볶음차보다 유리아미노산의 함량이 많았고, 녹차중에는 특히 threonine과 aspartic acid, lysine의 함량이 많았다. 3. Fructose, glucose, sucrose, raffinose등 4종의 유리당이 검출되었다. 4. 유리당은 가열시간 증가에 따라 각 성분의 함량이 현저히 감소하였다.

• 대한치과교정학회지
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• 제22권3호
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• pp.647-656
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• 1992

The purpose of this study was to evaluate the elastic memory process in cold worked stainless steel wire and the effect of heat treatment on it. 0.018 inch round and $0.019\times0.025$ inch rectangular wire (ORMCO stainless wire) were used in this study. Each wire type had 4 groups: non-heat treatment group, furnace heat treatment group, electric current heat treatment group, and bending after heat treatment group. Each group was consisted of 10 specimens. With the Jig, each wire was bent into v-shape uniformly, and width of two free ends of each v-shaped wire was measured by caliper (to the point of 0.1 mm correctly) at time interval of offjig, after heat treatment, 1, 2, 3, 4 hours, 1, 2, 3, 4, 5, 6 days, 1, 2, 3, 4 weeks after. The results were as follows: 1. In non-heat treatment group and bending after heat treatment group, elastic memory process was occured $60\%$ within 1 hour, and more than $90\%$ within 1 week. 2. In furnace and electric current heat treatment group, almost all elastic memory process was occured during teat treatment, and then specimen was stabilized dimensionally. 3. Magnitude of deformation by elastic memory was greater in heat treatment group than non heat treatment group and bending after heat treatment group. 4. There was no remarkable difference in deformation pattern between 0.018 inch round wire and $0.019\times0.025$ inch rectangular wire.