Application of oil‐in‐water emulsion in hot rolling process of brass sheet

Abstract

Purpose

The purpose of this paper is to develop a new oil‐in‐water (O/W) emulsion used for alpha phase brass, which can increase the antiwear and anti‐galling abilities of the rollers, and improve the surface quality of the rolled brass sheet. The aim is to evaluate the tribological performance of new kind of O/W emulsion for the hot rolling of alpha brass, which provides the fundamental information for the selecting of new chemical group, and to understand the lubrication mechanism of the used rolling emulsion and to correlate the laboratory findings with those of industrial rolling of alpha phase brass.

Design/methodology/approach

According to the hydrophile‐lipophile balance theory and the evaluation results of friction, wear and lubrication using a four‐ball tribometer, a novel O/W emulsion was developed for the hot rolling process of CuZn₃₂(ASTM C26200) and CuZn₃₀(ASTM C26000) alloys by controlling the composition of the emulsion, such as emulsifying, antiwear, extreme pressure, antirust and so on. By scanning electron microscope (SEM), energy‐dispersive X‐ray (EDX), and roughness profile the tribological mechanism were studied.

Findings

The production result proved that it was easy to control the accuracy and size of the brass sheet because of the emulsion‐jet to the roller surface directly and in succession. Polyol with hydroxyl group is found to provide better lubrication and lower coefficient of friction. The actual hot rolling results proved that it was easy to control the accuracy and size of the brass sheet with the emulsion jet. The morphologies and roughness profile of the copper sheet surface were observed and measured by SEM and topographic meter under different lubricant conditions. The in situ results supported the selection of compositions of O/W emulsion. The suitable temperature of feed emulsion is over 20°C.

Research limitations/implications

The tribological mechanism of friction modified emulsion is not still clear. The thermal mechanical properties of rollers under this kind of emulsion are also worth studying in the future.

Practical implications

Understanding the tribological behaviour of O/W emulsion, will be useful for emulsion chemists, tribologists and rolling mill users.

Originality/value

The current study shows new compositions of O/W emulsion used for hot rolling of alpha phase brass.

Citation

Hu, X., Wang, Y. and Jing, H. (2010), "Application of oil‐in‐water emulsion in hot rolling process of brass sheet", Industrial Lubrication and Tribology, Vol. 62 No. 4, pp. 224-231. https://doi.org/10.1108/00368791011051080