• 제목/요약/키워드: after-treatment process

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AISI 9310강의 침탄열처리 경로가 조직 및 잔류응력 변화에 미치는 영향 (Effect of Carburizing Heat Treatment Process on Microstructure and Residual Stress Changes in AISI 9310 Steel.)

  • 정영철;배주현;박재만;오승준;성장현;노용식
    • 열처리공학회지
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    • 제37권3호
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    • pp.128-137
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    • 2024
  • In this study, the carburizing heat treatment process used in aircraft gear manufacturing was compared with the general carburizing heat treatment process using AISI 9310 steel. The process of carburizing followed by slow cooling, and then quenching after austenitizing(Process A) showed less compressive residual stress and less retained austenite in the surface layer compared to the process of quenching directly after carburizing(Process B). In prpcess B, there was a large amount of retained austenite when quenched immediately after carburization, and when treated with subzero, martensite rapidly increased and the compressive residual stress increased significantly, but at the same time, there is a risk of cracking due to severe expansion in volume. Therefore, in the case of aviation parts, it is believed that a step-by-step heat treatment cycle was adopted to ensure stability against heat treatment cracks. As a result of the final tempering after sub-zero treatment, the A process specimen showed a deeper effective case depth and HV700 depth and a higher hardness value above HV700 than the B process specimen.

DTP(Digital Textile Printing)용 후처리 및 연속공정 시스템에 관한 연구 (Research on Continuous After-Treatment Process and System for DTP(Digital Textile Printing))

  • 박순영;전동원;박윤철;이범수;조항성
    • 패션비즈니스
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    • 제15권5호
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    • pp.43-54
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    • 2011
  • Digital Textile Printing(DTP) is appropriate for quick response system(QRS) and is closely connected with high value added fashion industry. Fashion products of high price are mainly silk and cotton. For high quality DTP products, it is important to optimize the parameters of media, pre and after-treatment, ink, printer, etc. DTP for these two fiber materials is also accompanied certainly with steaming as after-treatment process for coloration. Role of steam is like water in exhaustion dyeing. Steam can diffuse dye or ink in printing paste to fiber. Quality of DTP products depend on after-treatment processes such as steaming, washing, drying. Current production amount of DTP is smaller than one of conventional textile printing. However conventional after-treatment system has been using so far. This is mismatched with DTP in terms of process efficiency, spot work of small lot, quality control. In this study, continuous after-treatment system has been suitably designed for DTP that washing and drying are available after steaming. So, It is possible to improve efficiency of DTP process. Especially, the effects of after-treatment process, such as temperature of heat drum, steaming time on printability, color difference, color fastness were examined. Two types of samples(cotton knit and silk fabrics) were used. The results were obtained as follows : First, there is no a wide difference between the K/S values of cotton and silk treated with continuous after-treatment system and those of sample treated with conventional printing after-treatment method. So it is more effective to use the continuous after-treatment system than conventional printing after-treatment system in case of the daily throughput of 1,000 yards below. Second, after continuous after-treatment for DTP, K/S values were increased and lightness($L^*$) values were decreased. ${\Delta}E$ values were below 2.3. Third, DTP samples treated with continuous after-treatment system were tested for fastness(washing, light, rubbing). Grades of fastness(washing, light, rubbing) were above 3 grade.

Fenton 산화공정과 Zeolite 흡착공정을 연계한 축산폐수처리에 관한 연구 (A Study on Treatment of Livestock wastewater using Fenton Oxidation and Zeolite Adsorption Process)

  • 조창우;김윤정;정팔진
    • 한국물환경학회지
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    • 제21권5호
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    • pp.505-510
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    • 2005
  • The objective of this study was to remove non-biodegradable matters and ammonia ion in livestock wastewater using Fenton oxidation and Zeolite adsorption process. After coagulation process as 1st treatment, non-biodegradable matters remained after 1st treatment were removed by using OH radical produced in Fenton oxidation process. Zeolite as cation adsoption process was used to remove ammonia ion in 2nd treatment water. As a result of treatment using these processes, NBDCOD removal efficiency was over 90% and ammonia ion was almost removed. Most aromatics or polynuclear aromatics like benzene, phenol and scatol in livestock wastewater wasn't detected after Fenton oxidation process.

알루미늄 6061 합금 양극산화 후 열처리에 따른 표면 특성 관찰 (Effects of Heat Treatment on Surface Properties of Aluminum 6061 Alloy After Anodization)

  • 이승민;정찬영
    • Corrosion Science and Technology
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    • 제21권6호
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    • pp.495-502
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    • 2022
  • Anodization is a representative electrochemical surface treatment method that can improve both heat resistance and corrosion resistance by forming an anodization film on the surface of the aluminum. However, these properties can be changed after an additional heat treatment process. In this study, Al 6061 was subjected to an anodization process at 60 V for 1 hour, 5 hours, or 9 hours. An additional heat treatment process was performed at 500 ℃ for 30 minutes. Field emission scanning electron microscopy (FE-SEM) analysis revealed that the thickness of the anodized film was increased in proportion to the anodization time. Both pore size and pore diameter of the anodized film was also increased after anodization. After an additional heat treatment process, there were no significant changes in the thickness, pore size, or pore diameter of the anodized film. Heat resistance was confirmed through thermal analysis and chemical resistance was evaluated with a potentiodynamic polarization test.

소화탈리액 대상 오존 전처리와 Ultra Violet-Advanced Oxidation Process 연계 처리를 통한 유기물질 지표 개선 (Improvement of Organic Substances Indicators by Linked Ultra Violet-Advanced Oxidation Process After Ozonation for Anaerobic Digested Wastewater)

  • 이재엽;제스민아터;김일호
    • 상하수도학회지
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    • 제37권5호
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    • pp.253-259
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    • 2023
  • Bioreactors are devices used by sewage treatment plants to process sewage and which produce active sludge, and sediments separated by solid-liquid are treated in anaerobic digestion tanks. In anaerobic digestion tanks, the volume of active sludge deposits is reduced and biogas is produced. After dehydrating the digestive sludge generated after anaerobic digestion, anaerobic digested wastewater, which features a high concentration of organic matters, is generated. In this study, the decomposition of organic carbon and nitrogen was studied by advanced oxidation process. Ozone-microbubble flotation process was used for oxidation pretreatment. During ozonation, the TOC decreased by 11.6%. After ozone treatment, the TOC decreased and the removal rate reached 80.4% as a result of the Ultra Violet-Advanced Oxidation Process (UV-AOP). The results with regard to organic substances before and after treatment differed depending on the organic carbon index, such as CODMn, CODCr, and TOC. Those indexes did not change significantly in ozone treatment, but decreased significantly after the UV-AOP process as the linkage treatment, and were removed by up to 39.1%, 15.2%, and 80.4%, respectively. It was confirmed that biodegradability was improved according to the ratio of CODMn to TOC. As for the nitrogen component, the ammonia nitrogen component showed a level of 3.2×102 mg/L or more, and the content was maintained at 80% even after treatment. Since most of the contaminants are removed from the treated water and its transparency is high, this water can be utilized as a resource that contains high concentrations of nitrogen.

열처리가 냉간가공한 stainless steel wire의 복원양상에 미치는 영향 (EFFECTS OF LOW-TEMPERATURE HEAT TREATMENT ON ELASTIC MEMORY PROCESS OF COLD WORKED STAINLESS STEEL WIRE)

  • 오정세;박수병;손우성
    • 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.

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Bacillus subtilis를 이용한 폐수처리 효과연구: 오존의 영향을 중심으로 (Study of wastewater-treatment's efficiency using Bacillus subtilis: with an effect of ozonation)

  • 박영규
    • 환경위생공학
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    • 제17권4호
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    • pp.29-38
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    • 2002
  • Advanced oxidation of wastewater was studied with a purpose to remove TOC and color by the ozone-assisted Fenton reaction. The optimal conditions were determined by hydrogen peroxide and ozone concentrations. Experimental results indicate that the ozone treatment after Fentons process was found to provide very efficient removal efficiency in the process, avoiding the exclusive ozone treatment. The combined process of ozone in the Fenton oxidation respectively was increased removal efficiences of 10.7% in comparison with exclusive Fenton oxidation. Also, the treatments of ozone after Fenton's oxidation respectively had increased the removal efficiences of 16.%. As a result, the treatment of ozone after Fentons oxidation had the best removal efficiency of approximately 96%. Removal efficiency of color was significantly increased as mush as 26% by the advanced Fenton's oxidation in comparison with exclusive Fenton's oxidation. The removal efficiencies in the biological treatment using Bacillus subtilis after Fenton's oxidation and after Fenton's and ozone's oxidation were increased by 14% and 19% respectively. Although these combined Bacillus subtilis-assisted Fenton's oxidation was determined to be effective method to treat the dyeing wastewater in an economic point of view, the choice of wastewater treatment can be varied depending on water quality.

STD61 강의 내열특성향상을 위한 표면경화에 관한 연구 (A Study in the Heat Resistance Properties of STD61 Steel using the Surface Hardening Method)

  • 이구현
    • 연구논문집
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    • 통권26호
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    • pp.121-132
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    • 1996
  • The carburising surface modification treatment of the die steel has been used for improving wear resistance and heat cycle strength of the die and preventing a pitting on the surface because the carbides are forming in the matrix during carburising. Generally, the hot forging die was used after quenching-tempering treatment or nitriding after quenching-tempering treatment. The nitriding after carburising on the surface of a hot die steel and a wear resistance die steels was suggested by SOUCHARD, JACQUOT. and BUVRON. This surface modification treatment improved the adhesive and abrasive wear resistance and friction coefficient. The process was introduced to the forging die of stainless steel, titanium alloy steel, alloy and medium carbon steel and the physical properties of the die after the treatment were improved. The surface hardening treatment of the nitriding, the carburising, the boriding, and TD process were used to improved the life time of the forging die. Also, the coating process of PVD, CVD and PCVD were used and the hard chromium plating was occasionally used. Therefore, this study analyzed the effects of the carburising time and the conditions of nitriding on STD61 steel. The case depth, the surface hardness, the forming carbide size and shape during overcarburising process on the die steel were also examined.

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생물학적 폐수처리시 수질 경도에 따른 처리효과 연구 (Effect of Water-Hardness in the Biological Wastewater-treatment)

  • 박영규
    • 환경위생공학
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    • 제19권3호
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    • pp.58-64
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    • 2004
  • Biological treatment of wastewater was studied with a purpose to remove TOC by the reduction of water hardness. The optimal conditions of coagulant were determined by reaction time and amount of coagulant. Experimental results indicate that the biological treatment after physico-chemical treatment was found to provide very efficient removal efficiency in the process to treat the textile wastewater, including the carbon dioxide treatment. The combined process of carbonization in the physico-chemical treatment respectively was increased the removal efficiencies of $30.0\%$ in biological treatment in comparison with exclusive biological treatment. As a result, the treatment of hardness after carbonization had the best removal efficiency of approximately $60.0\%$. The removal efficiencies in the exclusive biological treatment using Bacillus subtilis and after carbonization were increased by $38.9\%\;and\;69.0\%$ respectively. The combined Bacillus subtilis-assisted biological treatment was determined to be the most effective method to treat the textile wastewater in an economic point of view, the water quality in the wastewater treatment plays an important role.

전응집 및 Fenton 산화공정을 이용한 축산폐수의 난분해성물질 제거특성에 관한 연구 (Degradation Characteristics of Non-biodegradable Matters using Pre-Coagulation and Fenton Oxidation Process in Livestock Wastewater)

  • 조창우;김병용;채수천;김선애;정팔진
    • 한국물환경학회지
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    • 제22권1호
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    • pp.66-73
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    • 2006
  • The purpose of this study was done to evaluate degradation characteristics of non-biodegradable organic matters including aromatic compounds in livestock wastewater using CFZ process. The CFZ process is consisted of coagulation/sedimentation, Fenton oxidation and zeolite adsoption process. degradation charateristics of each treatment water including livestock wastewater were analyzed by UV scanning, FT-IR and GC/MS. After coagulation/sedimentation process as 1st treatment, non-biodegradable matters remained after 1st treatment were removed by using OH radical produced in Fenton oxidation process. As a result of treatment using these processes, NBDCOD removal efficiency was over 90%. Increase of $E_2/E_3$ ratio (absorbance at 250 and 365 nm) in each treatment water means that aromaticity of livestock wastewater decreased. In case of GC/MS, most aromatics or polynuclear aromatics like benzene, phenol and scatol in livestock wastewater almost wasn't detected after oxidation using OH radical.