Abstract
This paper describes the elevated temperature testing of high and low carbon steels in the temperature range 500degrees-750degreesC and at strain rates of 3.3 x 10(-4) s(-1) and 3.3 x 10(-3) s(-1). The purpose of the testing was to simulate testing conditions during dieless drawing such as the forces involved at elevated temperatures and the effects they have on the mechanical properties of the material such as tensile strength and engineering strain.
The dieless drawing machine under construction consists of stepper motor driven ball-screws applying an axial load to the specimen and moving a band heater and cooling system along the specimen axis. Control of the process velocities and temperature allows diametrical control of the bar/wire to be achieved. The specimen on the dieless machine will be fixed at one end and axially loaded when a target temperature is reached, and when the yield strength is reached a local deformation is initiated. After a deformation increment the heating zone is moved toward the undeformed end of the bar/wire, while the cooling system decreases the temperature behind the heating zone and retards plastic flow at this position. Incremental movement of the heating/cooling zone means steady state conditions are achievable.