http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
논문 : 기계적 성질 ; 보론 첨가 고강도강의 수소지연파괴 저항성에 미치는 입계 페라이트의 영향
김지수 ( Ji Soo Kim ),이유환 ( You Hwan Lee ),이덕락 ( Duk Lak Lee ),이종수 ( Chong Soo Lee ) 대한금속재료학회 ( 구 대한금속학회 ) 2007 대한금속·재료학회지 Vol.45 No.9
In this study, the effect of intergranular ferrite volume fraction on the hydrogen delayed fracture (HDF) resistance of high strength boron-added steel was investigated. For this purpose, constant loading test using cathodically charged specimens was conducted on the three intergranular ferrite volume fractions, i.e., 000, 6% and l0%. With the increase of the amount of intergranular ferrite volume fractions, the HDF resistance in boron-added steel was increased. TEM and SEM observations revealed that the intergranular ferrite took the carbides nucleation sites at grain boundaries, and as a result, the crack nucleation sites were reduced. And the result of thermal desorption analysis showed that the grain boundaries were the main trapping sites.
격자 볼츠만 방법 방법(Lattice Boltzmann Method)을 이용한 다공성 매질내에서의 열전달 특성 특성에 관한 연구
황중기(Joong-Ki Hwang),최도형(Do-Hyung Choi),손일헌(Il-Heon Son),이덕락(Duk-Lak Lee),임성욱(Seong-Wook Yim) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
The heat/mass transfer characteristics of a porous medium in two and three-dimensions are investigated by using the Lattice Boltzmann Method to analyze the ball packed-bed regenerator of reheating furnace in steel rolling process. To obtain the bulk properties of the porous medium of various structures, calculations have been performed for porous media of regularly distributed inclusions.. It is found that the thermal dispersion is influenced by the medium structures, the Peclet number, the volume fraction of the solid, the thermal conductivity ratio of the solid and the fluid, and the Reynolds number. The streamwise thermal dispersion coefficients increase with the Peclet number, the volume fraction of the solid, the Reynolds number, and the thermal conductivity ratio of the fluid to the solid. The parameter that affects the thermal dispersion most is the Peclet number
황중기(Joong-Ki Hwang),손일헌(Il-Heon Son),이덕락(Duk-Lak Lee) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
A coupled thermal and metallurgical mathematical model and off-line simulator have been developed to simulate the Stelmor process for controlled cooling of steel wire rod. In order to solve one-dimensional transient heat transfer equation including the heat evolved from phase transformation, a finite difference method coupled with thermodynamic and kinetic analysis was employed. This model takes into account the temperature-dependent heat transfer and thermophysical properties and stresses the importance of the enthalpy of transformation. A developed model and off-line simulator have been shown to simulate the complex heat flow in the Stelmor process excellently and calculated results were in good agreement with measured temperature.
변태 전 오스테나이트 크기가 중탄소강의 재질편차에 미치는 영향
李德洛 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.6
The effect of prior austenite grain size on mechanical properties in a medium carbon ferrite-pearlite steel was investigated to find the optimum condition to minimize the deviation of mechanical properties. It is shown that the variation of hardness of a medium carbon steel containing ferrite and pearlite with cooling rate becomes smaller as prior austenite grain size becomes finer. The hardness of specimen with fine prior austenite grain increases less sharply than that of specimen with coarse one for the change of same amount of pearlite volume fraction in as-rolled state. It is concluded that the deviation of mechanical properties of medium ferrite-pearlite carbon steels can be reduced effectively by making prior austenite grain size finer.
주웅용,이덕락,Yue, Steve 대한금속재료학회(대한금속학회) 2001 대한금속·재료학회지 Vol.39 No.6
Inferior drawability of AISI4135 steel rod is sometimes due to the presence of hard constituents such as bainite and martensite in the microstructure of as-hot rolled state. The amount of hard phases can be minimized by controlled rolling, thus refining the austenite grains, which, in turn, shift the CCT diagram towards shorter times. For the same cooling rate, the austenite to ferrite-plus-pearlite transformation is accordingly enhanced. In conducting numerous hot torsion tests, equations describing the recrystallization behavior of AISI4135 steel during hot deformation were developed in order to find the best condition for grain refinement. Austenite grain sizes predicted by the equations are in good agreement with data from commercial rod rolling.