Thermoelectrically Based Approaches to Reduce Adhesive Wear During Blanking

Abstract

AbstractAlmost every metal mass product goes through a blanking process. Especially when processing aluminum, adhesive wear is the main determinant of cost efficiency. Many investigations on wear-influencing factors have been conducted so far, but one major determinant is almost unnoticed, thermoelectric phenomena. Due to the Seebeck effect, thermoelectricity arises in every blanking tool. Recently published investigations show that the combination of tool and workpiece materials has a strong influence on occurring thermoelectric currents and thus on adhesive wear development. This can be traced back to dependence of the current strength and direction on the material-specific Seebeck coefficient. This article addresses the same phenomenon for a new parameter spectrum. Blanking experiments with aluminum EN AW 5083 were performed, investigating both thermoelectric currents and the amount of adhesive wear. Furthermore, the impact of external currents influencing the naturally occurring thermoelectricity on wear is shown. Improved measurements with a laser confocal microscope reveal a close correlation between the thermoelectric current profiles and adhesive wear pattern on the lateral surface of the punch. Together with a variation of tool material among high-speed steel 1.3343, stainless steel 1.4301 and cemented carbide CF-H40S, a strong relation between the Seebeck coefficients, electrical currents and tool wear could be found. Therefore, the actual findings confirm, deepen and extend previous results concerning thermoelectricity and adhesive wear.