A Study on Plastic Working of Alloys in their Mashy State

Abstract

SummaryIt is well known that flow stress of metal decreases as its temperature rises. This property is applied to various hot plastic workings. Some working processes are now being developed which include metal deformation in the temperature range over solidus line, such as extrusion casting, ACURAD process and continuous casting at high speed. In order to study these processes, it is very important to get the basic data (little of which is known) on flow stress and flow behaviour of metal in the temperature range over its solidus line.Bearing this in mind, the authors made compression tests on the alloys of Pb-Sn and Al-Cu in their mashy state (that is in the temperature range over solidus line). The results of the compression tests were as follows (1) the relationship between flow stress and the solid fraction was clarified (2) according to the decrease of solid fraction from 100 per cent to 75 per cent, the flow stress decreases to (3) the alloys in their mashy state fracture in the strain range of 3–10 per cent in uni-axial deformation From the extrusion tests, the following results were obtained. (1) bars were successfully extruded in the reduction of 75−99·94 per cent (2) pipes were successfully extruded in the reduction of 74·7−93·4 per cent (3) by selecting an optimum temperature, sound products can be obtained at small extrusion force and at high speed.