Friction plays a significant role in metal-forming operations. To optimize the deformation process, it is necessary to quantify and evaluate the behavior of the lubricants. In this study, the lubrication behavior of A5 glass lubricant was investigated. Ring compression tests were conducted at constant strain rates ranging from 0.05 to 15 s-1 and at temperatures ranging from 750 to 1000℃. At temperatures lower than 950℃, the strain rate has no obvious effect on the friction factor of A5, the most significant parameter being the temperature, an increase in the temperature decreases the friction factorm to reduce. At A5 temperatures above 950℃, the effect of strain rate becomes important, the friction factor m increases with the decrease in the strain rate.

In this paper, clad sheet bonding by cold rolling has been analyzed in depth using the stream function method and the upper bound theorem. Not only have the curvature, the thickness ratio of the rolled product and rolling force, but also the locations of the neutral points and the bond point have been obtained. It is found that at low total thickness reduction, the neutral point on the upper roll contacting the harder sheet usually more closely approaches the entrance of the roll-gap than does neutral point on the lower roll. As the thickness reduction increases, the difference gradually diminishes and even reverses. It is also found that the location of the bond point at the interface is to some extent related to the initial clad ratio. A smaller the clad ratio before rolling may bring the bond point closer to the entrance of the roll-gap, which means a longer bonded length at the interface. Based on this analysis, some means of contributing to the promotion of bond strength are proposed.

The compression test has been used widely in obtailning flow stress data at hot working temperatures, in order to obtain reliable data, Uniform deformation must be ensured by having adequate lubrication tbrougbout testing, in tbis paper, the lubrication bebavior of graphite was investigated by ring compression tests of Ti-6A1-4V alloy at temperatures from 750 to 1000℃ and constant strain rates from 0.05 to 15s 1. it was found that the friction factor m increases with the increase of temperature and with the decrease of strain rate. At temperatures below 800℃, the friction factor m is less than 0.3, so that graphite can be used effectively as a luhiicant in this range of temperatm-e for compression tests.