HUANG Dianbing
,
KONG Lingtan
,
LIN ZongcaiUniversity of Science and Technology Beijing
,
Beijing. China
金属学报(英文版)
The oxidation rate of magnetite concentrate is ery quick at the reaction beginning, but it becomes much slower when the reaction is conducted to a certain level because the product layer on the micro particles resists the oxygen diffusion greatly. This phenomena are proved through experiments. And a function is put forward to calculating the quivalent osmosing thickness of the product layer. Based on the function, a mathematical model is established for the whole range reaction process of magnetite in pellets. It is proved that this model fits the real process very well under any condition.
关键词:
Magnetite
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QIAO Lijie LIU Rui XIAO Jimei University of Science and Technology Beijing
,
Beijing
,
China
金属学报(英文版)
The effects of stress components on nucleation sites and propagation directions of stress cor- rosion cracks in brass were investigated with specimens under mode Ⅱ and mode Ⅲ loadings. The results indicated that under mode Ⅱ loading,stress corrosion cracks nucleated on the site with maximum normal stress component and propagated along the plane perpendieular to the maximum normal stress,under mode Ⅲ loading,the stress corrosion crack was not evident on the 45°plane due to the general corrosion in aqueous solution with high NH_4OH concentra- tion,while stress corroded in aqueous solution with low NH_4OH concentration, numerous cracks with spacings of 10—150μm were found on the 45°plane with maximum normal stress and no stress corrosion cracks was observed on the plane with maximum shear stress.
关键词:
stress corrosion cracking
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