Jian Lin Sun

Research on Lubrication Behaviors of Nano-TiO2 in Water-Based Hot Rolling Liquid

In this paper, nano-TiO2 particles with an average size of smaller than 25 nm, were stable dispersion to water-based hot rolling liquid for steel strip under the effects of dispersant and ultrasonic. The stability of the rolling liquid with nano-TiO2 was characterized by sedimentation method. The tribological properties of the hot-rolling liquid doped with nano-TiO2 were evaluated by using a universal friction and wear tester. Besides, the lubricity of the water-based hot rolling liquid doped with nano-TiO2 for steel strip was evaluated on a hot-rolling tester by using the rolling liquid without nano-TiO2 for comparison. Results indicate that TiO2 Nano-particles as additive are stable dispersion to hot-rolling liquid with appropriate dispersant and process for more than 7 days, also have good friction-reducing, anti-wear, and cooling properties.

Study on the Lubricating Performance of Nano-TiO2 in Water-Based Cold Rolling Fluid

A type of water-based cold rolling fluid has been developed by adding TiO2 nanoparticles. The tribological behavior of nanoTiO2 water-based rolling fluid was investigated by using four-ball machine. The worn surfaces of the steel balls were analyzed by using OLYMPUS laser confocal microscopy. Results indicate that nanoTiO2 nanoparticles significantly improved the anti-wear properties in the way of micro-ball bearing and perfecting the tribological behavior of water-based rolling fluid. The cold rolling experiment shows that the nanoTiO2 water-based rolling fluid had a good rolling lubricant performance under the condition of concentration of 0.7wt.% for the upper limit. The nanoTiO2 water-based rolling fluid can not only decrease the minimum rolling gauge and the surface roughness of the work piece, but also prevent direct contact between roller and work piece which could lead to the rolled surface scratches and adhesion defects.

Lubricating Performances of Nano Organic-Molybdenum as Additives in Water-Based Liquid during Cold Rolling

The non-parathion nano organic molybdenum (Nano-Mo) was adopted to substitute for the conventional extreme-pressure and anti-wear additives, uniformly dispersed in water-based cold rolling liquid for steel strips. The tribological properties of the water-based cold rolling liquid were tested by the four-ball machine, and the lubricity of the cold-rolling liquid for steel strip was evaluated on the 4-high cold rolling experiments. Besides, the worn surfaces of the steel balls were observed by an optical microscope. Results indicated that Nano-Mo as additive in water-based cold rolling liquid, compared with the conventional emulsions, PB values was increased by 4%, and friction coefficient and wear scar diameter were decreased by 10.8% and 13.1%, the lubricity of rolling liquid was verified by cold rolling test which showed that this liquid had the excellent lubricant performance to reduce the rolling force, save energy consumption and get thinner strip. Optical microscope was used to observe the strips surface which showed that strip surface streaks were clear, scratches were less and shallow. By roughness test and EDS analysis, defects were filled with nanoparticles, friction and wear were reduced effectively. In addition, tensile properties had been studied after rolling lubrication, but the results showed no significant effect.

Elastic Constants and Thermodynamic Properties of Cu, Cu2O and CuO from First-Principles Calculations

Elastic constants and some thermodynamic properties of Cu and copper oxides were studied by first-principles total energy calculations. The elastic constants of Cu and copper oxides were calculated on pressure. It was shown that the calculated elastic constants of Cu, Cu2O and CuO at zero pressure were well consistent with previous experimental data. The specific heat capacities and thermal expansion coefficient of Cu and copper oxides were successfully obtained. The calculated specific heat capacities of Cu were well consistent with the previous experimental data.

QSAR Study on Imidazole Derivatives as Corrosion Inhibitors by Genetic Function Approximation Method

Quantitative structure and activity relationship (QSAR) method is becoming more desirable for predicting of corrosion inhibition properties. The inhibition efficiency of organic compounds is dependent on many basic molecular descriptors, including structural descriptors, thermodynamic descriptors, information content descriptors, topological descriptors as Wiener index, Zagreb index and molecular connectivity indices. A genetic function approximation approach was used to run the regression analysis and establish correlations between different types of descriptors and measured corrosion inhibition efficiency for imidazole derivatives. A QSAR equation was developed and used to predict the corrosion inhibition efficiency for 18 imidazole derivatives. The prediction of corrosion efficiencies of these compounds nicely matched the experimental measurements.

Research on the Formation Mechanism of Emulsion Spots on the Cold-Rolled Silicon Steel Surface

For the cold-rolled silicon steel strip lubricated with emulsion, the typical oil spot defects always can be found on the surface of rolled strip. The oil spot are parallel to the rolling direction. In the present study the micro-structure of oil spot defects was investigated by several surface analysis techniques, including LEXT ols4000 laser scanning confocal microscope, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS). The chemical compositions of the oil spot defects were analyzed by EDS. The results showed that the surface quality of the rolled non-oriented silicon steel was affected strongly by emulsion stability. The emulsion stability decreased with the increasing content of CL-. When the particle size of emulsion was larger, the lubricity of the emulsion deteriorated. Furthermore, there were some emulsions which contain miscella on the strip steel surface. The emulsions existed in the confined areas where the plate shape defects formed. The majority of its water was evaporated with the increasing of temperature and time. The oxides and residual emulsions could be found on the surface strip steel, which originated from the oxidation reaction between vapors and silicon steel surface. Eventually, the reaction produced some oxides (Fe3O4, FeO, Fe2O3, SiO2, CoCr2O4, NiCr2O4, Fe-Cr) and other by-products. In addition, the emulsion spots area were easier to suffer corrosion than the normal area under the same conditions.

Investigation on the Corrosion Behavior of Emulsion on the Cold-Rolled Silicon Steel Surface

The silicon steel was cold rolled by using an oil-in-water emulsion for lubricating its surfaces. Oil in water (O/W) emulsion is a lubricant composed of oil in the form of droplets suspended in water. This paper mainly researched on the new emulsion which was prepared by changing the compound proportion between antioxidant 2, 6-Di-tert-butyl-p-cresol (T501) and antirust agent petroleum sodium sulfonate (T702). The corrosion behavior of the emulsion was investigated by weight loss and electrochemical methods. The mechanisms for inhibition of corrosion synergism between T501 and T702 in base oil were studied. The results show that the antirust agent (T702) can effectively forming a layer of adsorption film on the rolled strip surface and this adsorption film can segregate strip surface from air and water. The antioxidant (T501) can capture oxygenic free radical (•OH, RO•, ROO•) and carbon free radical and reduces the trend which emulsion occur oxidation reaction under high temperature and high pressure. The antioxidant plays a minor role in inhibition of corrosion synergism. The results show that the best compound proportion content is 4% antioxidant (T501) and 8% antirust agent (T702), which can effectively increase the anticorrosion effect of emulsion. Meanwhile, the self-corrosion potential and self-corrosion current of the sample is minimal and the self-corrosion current is 1.0226×10-7A/cm2.

Lubrication Mechanism of Nanoparticles in Metal Hot Deformation

Effect of nanoparticles to improve the lubrication load capacity and resistance to extreme pressure of water-based rolling liquid was studied by four-ball tester. Compression experiments were conducted in different lubrication conditions with nanoparticles using Gleeble hot compression simulation machine. Then the residual nanoparticles characteristics and the surface morphology of the compressed sample were analyzed by SEM and EDS. The results show that water-based nanoTiO2 lubricant can efficiently reduce the friction during metal deformation. nanoZnO is preferred to adhere to metal surfaces and employed to isolate the surfaces. A new lubricating mechanism of nanoparticles in metal hot deformation named convex peak extreme pressure buffering mechanism is thereby proposed, which is verified by the surface morphology of compressed sample.

Research on Lubricating Properties of Alcohol and Ester in Stainless Steel Cold Rolling Process

aliphatic ester, aliphatic alcohol, stainless steel, cold rolling oil Abstract: In this paper, the deeply hydrogenated mineral oil 60N was used as base oil. The additives such as mixture of dodecanol and tetradecyl alcohol, hexadecanol alcohol, octadecyl alcohol, ethyl hydride laurate, methyl palmitate and butyl stearate were separately added to the base oil by 10 percent. Evaluate its physical and chemical properties, and cold rolling experiments were carried out on both 202 and 304 stainless steel lubricated by different rolling oil. The results showed that the aliphatic alcohol have better performance in lubricating and volatilizing properties than fatty acid ester. Moreover, the octadecyl alcohol showed the best lubricating properties compared with selected aliphatic alcohol.

Prediction of Ferrite Transformation in Nb-Containing Microalloyed Steels during Continuous Cooling

This paper considers for transformation behavior of Nb microalloyed steels, experiments had demonstrated the effect of Nb was obvious: lowered start temperature of ferrite transformation remarkably and forming more refined ferrite grain size. In this study, computer simulation of Nb-containing steels transformation during continuous cooling was carried out by adopting a classical nucleation and growth theory, the model was derived based on the theories and the experimental results, and the calculated start temperatures of ferrite transformation were compared with the results of experimental.