Influences of Friction and Metal Properties on Pure Stretchability of Sheet Metals

Abstract

The influences of the frictional coefficient at the tool-work interface and of the metal properties, such as n-value or r-value, on the stretchability of sheet metals have been examined both theoretically and experimentally. The optimum frictional coefficients for improved stretchability have been found by both numerical analysis and experiment. Their values become smaller as n- and r-values become larger. Stretchability can be markedly improved by reducing the frictional coefficient to less than 0.05, for sheet metals having an n-value of more than 0.2.