XIAO Kui
,
DONG Chaofang
,
LI Xiaogang
,
WANG Fuming
钢铁研究学报(英文版)
The formation and development of corrosion products on carbon steel surface during the initial stage of atmospheric corrosion in a laboratory simulated environment have been studied by scanning electron microscopy (SEM) and Raman spectroscopy. The results showed that two different shapes of corrosion products, that is, ring and chain, were formed in the initial stage of corrosion. MnS clusters were found in the nuclei of corrosion products at the active local corrosion sites. The ringshaped products were composed of lepidocrocite (γFeOOH) and maghemite (γFe2O3) transformed from lepidocrocite. The chaintype products were goethite (αFeOOH). A formation mechanism of the corrosion products is proposed.
关键词:
atmospheric corrosion;corrosion product;carbon steel
XIA Yunjin
,
WANG Fuming
,
WANG Jinlong
钢铁研究学报(英文版)
The secondary dendritic arm spacing (SDAS) of free cutting steel 38MnVS during continuous casting process was simulated based on a Mixed Lagrangian and Eulerian Method (MiLE Method) and SDAS model. The simulation results are basically in agreement with measured ones. The effect of composition, superheat and casting speed on SDAS are studied, and the relationship between SDAS and interdendritic segregation is discussed. The results show that SDAS increases with increasing carbon and silicon content, and decreases with increasing manganese and sulfur content. The increase of superheat and casting speed also makes SDAS increase. The permeability of columnar mushy zone which is parallel to the primary dendritic arms is calculated based on CarmanKozeny relationship, and the increase of SDAS makes the permeability increase, which exacerbates interdendritic segregation of columnar crystal zone.
关键词:
MiLE method
,
secondary dendritic arm spacing
,
permeability
,
interdendritic segregation
