Encapsulation Of Ultrafine Aluminum Alloy Powder And Preparation Of Cold Rolling Emulsified Oil With Solid Lubricant For Steel Sheet

After dozens of year endeavor, great achievements have been made in the research and development of the cold rolling emulsified oil for the steel sheet. But still there is no small disparity compared with overseas products of the same kind. Although imported foreign products have good product performance, there are still some problems such as the high price and delays in the supply chain. Consequently, it is urgent to resolve the issue of domestic. In addition, in view of the fact that it has not been reported to use the ultrafine aluminum alloy powder (Al-Cu-Fe) in the craft lubrication of cold rolling, we have developed a cold rolling emulsified oil with ultrafine aluminum alloy powder solid lubricant for steel sheet.It is essential to coat the ultrafine aluminum alloy powder because the powder can easily react with water and acidic material in the emulsion of cold roiling oil.In order to improve its corrosion resistance, two aluminum alloy powders with different particle size distribution were coated by the conventional and ultrasound-assisted sol-gel method employing tetraethoxysilane (TEOS) as the precursor and using the corrosion resistance and dispersibility of powder as the evaluation indicators. Many parameters were studied in the coating process such as solvent type, water concentration, precursor concentration, alkali concentration, reaction temperature, reaction time and nw:nTEOS.In addition, the study of ultrasound power and irradiation time on the encapsulation process was also carried out. Finally, the encapsulated aluminum alloy powder characterized not only good corrosion inhibition but also good dispersion. Combined with the FTIR, XRD, SEM, DLS and EDS analyses, it can be determined that a very thin silica layer had encapsulated on the surface of aluminum alloy powder.Components and contents of cold rolling emulsified oil for steel sheet were determined according to the tentative quality index of the product by analyzing Holland QUAKER and Japan DAIDO products. Two fatty acid esters were synthetized using the cheap and readily available raw material. Both of the two fatty acid esters exhibited good thermostability, oil solubility, anti-wear and extreme pressure performance.At first, the best HLB of oil-water system was obtained and then the best emulsifier compound was determined by the mixing experiments of emulsifier and emulsion plate-out experiments. The best extreme-pressure antiwear agent compound was determined by studying the effect of the contents of three extreme-pressure antiwear agents on the extreme pressure performance of oil. At the meantime, the best aluminum alloy powder solid lubricant compound was determined by studying the effect of contents of the two aluminum alloy powders on the anti-wear and extreme pressure performance of the oil.ZP-1A cold rolling emulsified oil for steel sheet was prepared with base oil, oiliness additive and additional agents in a specified order. In order to highlight the lubrication action of aluminum alloy powder in the rolling process, ZP-1 cold rolling emulsified oil for steel sheet, which did not contain the aluminum alloy powder, was served as the blank sample.Under the same experimental conditions, ZP-1, ZP-1A and DAIDO products were all applied on a four-high reversing mill in the pilot scale test of cold rolling. The qualities of ZP-1 and ZP-1A were evaluated by comparing rolling current, rolling force, the curve of rolling force changing with the rolling speed, the strip surface temperature and strip surface topography with DAIDO product. The conclusion was as follows. Ultrafine aluminum alloy powder solid lubricant significantly improved not only the lubrication performance, rolling stability of the product, but also the quality of strip surface topography. But oil film of ZP-1 and ZP-1 A fractured in the high speed milling, resulting in a sharp rise in the friction force. In short, lubrication performance of ZP-1A was better than that of overseas product in the low speed milling, therefore, ZP-1A can be used in the low speed milling(<2 m/s). But lubrication performance of ZP-1A was unsatisfactory in the high speed milling because of the appearance of the deep furrow and serious scratch. The problem can be resolved by increasing the proportion of oiliness additive of the oil or the emulsion plate-out.