Development of Hot Vacuum Rolling Technologies for Hard-to-machine Materials

The substance of our study is divided broadly into four groups as follows.1 Development of a high performance vacuum rolling millA test rolling mill has been developed that has capacities of the maximum temperature 1100°C，the rolling speed10mpm，the degree of vacuum10 Ii D15i D1Torr and the rolling load 390 kN，through arranging heating and cooling equipments in front and rear of the mill.We have invented a unique structure of rolling equipment to maintain the degree of vacuum，and two patents have been obtained(April 1999，Patent No.2909903 and 2920631).2 Elucidation of the rolling characteristicsMill modulus，screwdown hysteresis，heating/cooling characteristics，ultimate vacuum/vacuum maintaining characistic and so were measured and analyzed，to clarify the comprehive characuum/vacuum maintaining characistics and so were measured and analyzed，to clarify the compreling equipment of the degree of the vacuum of the vacuum and so were measured and analalyzed，Patent Pending241072).3 Research on hot rolling characteristics of TiAL intermetallicsA test material of a Ti-47Al-3Cr compound was manufactured to investigate its mechanical properties and metallic structures.As the results of research on its rolling characteristics at higher temperatures，it has been confirmed that a simple pack rolling is effective.4 Research on ferro-radical composite materialsA Ti-clad steel plate and a Cu-stainless clad steel plate were made on an experimental basis utilizing the vacuum atmosphere.Especially in case of the Ti-clad plate，a high boundary shearing strength of 250-270 MPa was obtained under the conditions of 950-1000℃and 10%of the draft.The optimum rolling method for the hard-to-machine materials has not been developed yet，and it is still important that the equipment and technology should be continuously improved.

The substance of our study is divided broadly into four groups as follows.1 Development of a high performance vacuum rolling millA test rolling mill has been developed that has capacities of the maximum temperature 1100゜C, the rolling speed 10mpm, the degree of vacuum 10ィイD15ィエD1Torr and the rolling load 390kN, through arranging heating and cooling equipments in front and rear of the mill. We have invented a unique structure of rolling equipment to maintain the degree of vacuum, and two patents have been obtained (April 1999, Patent No.2909903 and 2920631).2 Elucidation of the rolling characteristicsMill modulus, screwdown hysteresis, heating/cooling characteristics, ultimate vacuum/vacuum maintaining characteristic and so were measured and analyzed, to clarify the comprehensive characteristics of the whole equipments.An extra small diameter (30mm) roll-combined equipment was invented to endow the characteristic of heavy reduction, the patent on which is now pending (July 1999, Patent Pending 241072).3 Research on hot rolling characteristics of TiAL intermetallicsA test material of a Ti-47Al-3Cr compound was manufactured to investigate its mechanical properties and metallic structures. As the results of research on its rolling characteristics at higher temperatures, it has been confirmed that a simple pack rolling is effective.4 Research on ferro-radical composite materialsA Ti-clad steel plate and a Cu-stainless clad steel plate were made on an experimental basis utilizing the vacuum atmosphere. Especially in case of the Ti-clad plate, a high boundary shearing strength of 250-270MPa was obtained under the conditions of 950-1000゜C and 10% of the draft.The optimum rolling method for the hard-to-machine materials has not been developed yet, and it is still important that the equipment and technology should be continuously improved.