Development of Cold Rolling Oil for Tinplate with High Emulsion Stability Index
Tatsuaki Ishii, Satoshi Inagaki, Noboru Matsunaga, Da Ming Wang
In the previous study, a cationic rolling oil containing cationic and non-ionic emulsifiers was developed and was used for sheet gauge rolling in a tandem mill.In this study, the previously developed cationic rolling oil was further improved and applied to tinplate rolling, and it generated higher friction and pressure in the roll-bite than in sheet gauge rolling.The improved oil was formulated with a special agent to enhance its lubricity during high-speed rolling, and its emulsion stability was also improved by adjusting the emulsifier. The emulsification stabilities and plate-out properties of conventional non-ionic, the previously developed cationic, and the improved cationic rolling oils were investigated on a laboratory scale. In the emulsification stability test, the average particle size of the improved cationic oil solution was found to be reduced to less than half that of the previously developed cationic oil. In addition, the amount of plate-out film of the improved oil was three times higher than that of the conventional non-ionic rolling oil at 170°C. The plate-out properties on high-temperature specimens at 200°C with and without the special agent were also verified.Furthermore, the effectiveness of the improved oil was verified in an actual mill. The maximum rolling speed of improved oil was faster than that of the current rolling oil with nonionic emulsifier. Based on this result, the improved oil having better lubricity was confirmed.In conclusion, the improved oil can be used for tinplate production to maintain stable coolant with a high level of ESI.