Effects of heat separation of water-soluble polymers on the performance of solution-type rolling lubricants II--

摘要

In order to investigate the effects of the heat separation of water-soluble polyumers of the performance of solution-type lubricants in cold rolling of stainless steel, rolling tests were performed using lubricants containing several polymers andoiliness agents in water. It is suggested that a dissolved polymer, which is capable of heat separation, may be deposited on heated roll surfaces, enabling the resultant polymer-rich layer of higher viscosity to be dragged into the contact arc, leadingto greater liquid film thickness and lower contact ratio between roll and strip surfaces. This mechanism is supported by the experimental results that (1) the surface temperature of the work roll is sufficiently high to cause heat separation of polymersfrom solution, (2) a solution containing a polymer of higher viscosity exhibits better lubricity when solutions of the same bulk viscosity are compared, and (3) in the case of different polymer content, solutions containing the same polymer show nearlythe same lubricity unber the condition of high roll temperature, whereas these solutions provide different lubricity under the condition of low roll temperature. It is further found that an oiliness agent has distinct distribution characteristics in thepolymer layer after heat separation.