http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A New Fracture Analysis Technique for Charpy Impact Test Using Image Processing
박태창,김범석,손지희,여영구 대한금속·재료학회 2021 대한금속·재료학회지 Vol.59 No.1
The Charpy impact test is used to identify the transition between ductility and brittleness. The percentages of ductile and brittle fractures in steel can be evaluated based on each fracture area, which is presently determined by an analyzer with the naked eye. This method may lead to subjective judgement, and difficulty accurately quantifying the percentage. To resolve this problem, a new analysis method based on image processing is proposed in this study. A program that can automatically calculate the percentage of the ductile and brittle fractures has been developed. The analysis is performed after converting an RGB fracture image into a binary image using image processing techniques. The final binary image consists of 0 and 1 pixels. The parts with the pixel values of 1 correspond to the brittle fracture areas, and the pixel values of 0 represent the ductile fracture areas. As a result, by counting the number of 0 pixels in the entire area, it is possible to automatically calculate the percentage of ductile fracture. Using the proposed automatic fracture analysis program, it is possible to selectively distinguish only the brittle fracture from the entire fracture area, and to accurately and quantitatively calculate the percentages of ductile and brittle fractures.
박태창,고경수,윤순모,정봉근,서용기 한국분석과학회 2021 학술대회논문집 Vol.2021 No.11
차량 경량화는 연비 향상 및 배기가스 배출 감소를 위한 가장 현실적인 대안이며, 최근 고성능 프리미엄 차체를 중심으로 알루미늄, CFRP 등과 같은 경량화 소재의 적용이 확대되고 있는 추세이다. 경량화 효과를 고려하면 CFRP 소재가 가장 우수하나 비용이 비싸다는 단점을 가지고 있다. 반면에 알루미늄은 상대적으로 비용 대비 효과가 우수하고 자동차 내 적용 가능 부품도 다양하여, 현재는 가장 현실적인 경량소재로 주목을 받고 있다. 당사에서도 자동차용 알루미늄 확대적용을 위해 ICP-OES를 활용한 분석 의뢰 물량이 증가하고 있으나, 분석 성분 중 규소(Si)의 결과 재현성이 떨어지는 문제점이 발생되고 있다. 본 연구에서는 이러한 문제를 해결하기 위해서 기존 방법과 다른 새로운 알루미늄 샘플 전처리 조건에 관한 연구를 진행하였다. 결과 재현성 확보를 위해 염산과 과염소산을 이용한 2가지 산처리 적용 절차를 제시하였으며, 각 전처리 적용결과에 대한 비교검증을 통해 유효성을 확인하였다.
박태창,김범석,김태영,진일봉,여영구 대한금속·재료학회 2018 대한금속·재료학회지 Vol.56 No.11
The basic oxygen furnace (BOF) steelmaking process in the steel industry is highly complicated, and subject to variations in raw material composition. During the BOF steelmaking process, it is essential to maintain the carbon content and the endpoint temperature at their set points in the liquid steel. This paper presents intelligent models used to estimate the endpoint temperature in the basic oxygen furnace (BOF) steelmaking process. An artificial neural network (ANN) model and a least-squares support vector machine (LSSVM) model are proposed and their estimation performance compared. The classical partial least-squares (PLS) method was also compared with the others. Results of the estimations using the ANN, LSSVM and PLS models were compared with the operation data, and the root-mean square error (RMSE) for each model was calculated to evaluate estimation performance. The RMSE of the LSSVM model 15.91, which turned out to be the best estimation. RMSE values for the ANN and PLS models were 17.24 and 21.31, respectively, indicating their relative estimation performance. The essential input parameters used in the models can be selected by sensitivity analysis. The RMSE for each model was calculated again after a sequential input selection process was used to remove insignificant input parameters. The RMSE of the LSSVM was then 13.21, which is better than the previous RMSE with all 16 parameters. The results show that LSSVM model using 13 input parameters can be utilized to calculate the required values for oxygen volume and coolant needed to optimally adjust the steel target temperature.
박태창 ( Tae Chang Park ),윤혁원 ( Hyok Won Yoon ),조영준 ( Young Jun Jo ) 대한금속재료학회(구 대한금속학회) 2015 대한금속·재료학회지 Vol.53 No.1
Minute quantities of boron less than other added elements are able to improve various mechanical properties. To know the effect of boron on the properties of steel, it is necessary to accurately and precisely analyze it. It is easy to analyze boron in final products like thick plates and automotive steel sheets by OES, but it is impossible to analyze it in a sample like the ferro-alloy. An accurate analysis is also very difficult by ICP-OES because there is a matrix disturbance by the Fe element in the sample. In this work, instead of the existing specific procedures that are time-consuming for a matrix separation, we wanted to develop a quick and accurate method for analyzing boron by ICP-OES with the standard addition method. Three samples in this work, NCS HC 17204, NCS HC 23204 and JSS 174-7, were selected and used according to the boron content. When all the samples were analyzed using a wavelength of 182.583 nm of ICP-OES, we found that the analytic values corresponded to the certified values of CRM as follows. The certified value of NCS HC 17204 is 0.0042% and the analytic value was 0.0043%. The certified value of NCS HC 23204 is 0.0053% and the analytic value was 0.0052%. The certified value of JSS 174-7 is 0.0076% and the analytic value was 0.0080%. (Received January 15, 2014)