C Gheorghies
,
I Crudu
,
C Teletin
,
C Spanu
钢铁研究学报(英文版)
A theoretical model adapted for studying steel continuous casting technology was proposed. The model based on system theory contained input/output, command, and control parameters. The process was divided into five stages, ie, tundish, mold, guiding system, guidingdrawing system, and guidingdrawingsoft reduction system. The model can be used to describe the physicochemical processes, thermal processes, chemical processes, and characteristics of the cast material according to the abovementioned stages. It can also be applied to other metallurgical technologies and even to other industries (chemistry, food, etc).
关键词:
steel;casting technology;system theory;modeling
C Gheorghies
,
S ConduracheBota
钢铁研究学报(英文版)
Measuring the thickness of steel plates during the hot rolling process is crucial for getting the necessary feedback to obtain the desired values at room temperature. The dilatation and the phase transformations that steel suffers during it's heating and subsequent cooling when rolled strongly influence the results of thickness measurements. The radiometric method provides the necessary means to make real-time and fully automatized measurements of steel thickness during rolling, if only the temperature correction is precisely known and taken into consideration. This article proves that the experimental results concerning the relative variation of steel thickness and of it's corresponding mass-thickness variation can be correctly explained by means of the theory of metal dilatation correlated with the theory of nuclear radiation absorption when passing through a metal or metallic alloy, such as steel.
关键词:
steel;hot rolling;dilatation;phase transformation;temperature correction;gamma rays;X-rays;attenuation
C Gheorghies
,
L Palaghian
,
S Baicean
,
M Buciumeanu
,
S Ciortan
钢铁研究学报(英文版)
The way to characterize the behaviour of a naval steel grade E36 subjected to the corrosive fatigue process is investigated. The tests were carried out by bending fatigue of plate specimens with thickness of 10 mm in the corrosive environment consisting of an aqueous solution of 35% of NaCl which is similar to seawater. Experimental results show that the principal mechanism of degradation of the superficial layer is based on the pit evolution, evidenced by electrochemical, micro and macro structural timely changes such as evolution of electrode potential, evolution of current density, polarization resistance, anodic and cathodic parameters, and dislocation density evolution.
关键词:
naval steel
,
fatigue
,
pitting corrosion
,
structure
Author S.R. Zhou
,
S.R. Qiao
,
S.H. Bai and C.S. Tian Faculty 401
,
Northwestern Polytechnical University
,
Xian 710072
,
ChinaManuscript received 18 October 1998
金属学报(英文版)
The tensile properties of three different carbonfiberreinforced carbon composites (C/C), mat C/C, 2D laminate and 4D C/C, were investigated under the combined influence of temperature and loading rate. From the experiments the following could be concluded: loading rate between 10-1-10 mm/min was valid; the fracture stress of the three kinds of C/C composites increased with increasing temperature in the range from room temperature to 1900, and the initial modulus of 2D laminate C/C composites increased with the increase of temperature up to 2000.
关键词:
tensile testing
,
null
,
null
,
null
孙乐
,
方向青
,
孟广慧
材料科学与工程学报
doi:10.14136/j.cnki.issn 1673-2812.2016.05.027
通过化学气相渗透(CVI)、树脂浸渍/碳化(I/C)的工艺制成多孔的C/C预制件,采用气体压力浸渗方法向预制体中渗入铜,制备出C/C-Cu复合材料.以高密度C/C复合材料(1.9g/cm3)作为对比样,在MM-200型磨损试验机上对其摩擦磨损性能进行测试,并对其微观结构和摩擦磨损机理进行分析.研究结果表明:C/C-Cu的摩擦系数比C/C复合材料的低,这主要与摩擦表面的摩擦膜有关,铜在摩擦力带动下填充摩擦表面的凹坑,并与碳材料共同形成摩擦膜,摩擦膜的碳含量越高,润滑效果越好.当C/C预制件密度为1.59 g/cm3时,C/C-Cu的摩擦系数和磨损量均小于C/C复合材料,摩擦磨损性能良好.
关键词:
C/C-Cu
,
摩擦磨损
,
摩擦膜
Physical Review B
We report the electronic transport properties of a composite system comprising zero dimensional superconducting NbC(C) nanocapsules and carbon nanofiber matrix. DC susceptibility measurements of the nanocomposite indicate that the critical temperature (T-C) of NbC nanocrystals is 10.7 K. The temperature dependence of electrical resistivity of the specimen pellet follows the Mott's T-1/4 law in a temperature range between T-C of NbC and 300 K, owing to a strong degree of structural disorder in the carbon matrix. Below the T-C of NbC, when the change of its electrostatic energy Delta E is far greater than the thermal energy, an electron will be localized on an isolated NbC nanocrystal at very low temperatures, leading to "Coulomb Blockade." As a result, a collective behavior of the single-electron tunneling effect takes place in a three-dimensional granular superconductors' network composed of the NbC/carbon/NbC tunneling junctions. The superconducting gap of NbC crystals is not found in the current-voltage curves, due to the suppression of surface superconductivity through the contact between NbC and carbon shells.
关键词:
zero-dimensional superconductor;granular metal-films;particles;conduction;nanocapsules;percolation;samples
材料科学技术（英文）
Oxidation behavior of C/C-SiC gradient matrix composites and C/C composites were compared in stationary air. The results show that oxidation threshold of C-SiC materials increases with the amount of SiC particles in the codeposition matrix. Oxidation rate of C/C-SiC gradient matrix composites is significantly lower than that of C/C material. The micro-oxidation process was observed by SEM.
关键词:
carbon carbon composites
Jingyi DENG
,
Wenchuan LIU
,
Haifeng DU
,
Huiming CHEN
,
Yiyi LI
材料科学技术（英文）
Oxidation behavior of C/C-SiC gradient matrix composites and C/C composites were compared in stationary air. The results show that oxidation threshold of C-SiC materials increases with the amount of SiC particles in the codeposition matrix. Oxidation rate of C/C-SiC gradient matrix composites is significantly lower than that of C/C material. The micro-oxidation process was observed by SEM.
关键词:
