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The microstructure, mechanical properties, and hydrogen permeation behavior of hot rolled enamel steel were investigated. Three coiling temperatures were adopted to gain different sizes of ferrite grain and TiC precipitates. The results show that a large number of interphase precipitates of nano-sized TiC can be obtained at coiling temperatures of 650 and 700 °C, while a few precipitates are found in experimental steel when coiling temperature is 600 °C. The yield strength and ultimate tensile strength decrease with increasing coiling temperature, while elongation increases. The experimental steel has the best resistance to fish-scaling at coiling temperature of 700 °C, due to the large quantities of nano-sized interphase precipitates of TiC. [ABSTRACT FROM AUTHOR]

The analysis of the composition of chemical oxygen demand (COD) can provide a theoretical basis for the design of an efficient wastewater treatment process. In this study, the gradient membrane molecular weight division method was selected to create the COD fingerprint of the oil production wastewater. The chemical components and concentrations of the organic pollutants in the wastewater were analysed by gas chromatography-mass spectrometry, and the structures were qualitatively analysed by UV-Vis. Results showed that the types of aromatic hydrocarbons decreased from 163 to 96 in the advanced wastewater treatment, the types of straight-chain hydrocarbon organics were increased from 17 to 25, which changed from C14-C30 to C14-C38. By contrast, the total concentration of COD was decreased by 80.5% (from 237.5 mg/L to 46.3 mg/L). The organic pollutants in the wastewater were mainly aromatic hydrocarbons and straight-chain alkanes. The results also indicated that the removal of the petroleum macromolecules and soluble organics will be necessary for the treatment of the polymer-containing oil production wastewater. [ABSTRACT FROM AUTHOR]