Approximate Calculation Formula of Drawing Force by Curved Surface Die (2nd Report) : Yield limit is constant-its experiment

Abstract

This paper describes the experiment executed by the present author for the purpose of finding out how far the actual drawing coincides with the formula which the author had reported in his first report. The author measured the forces with which the low carbon steel was actually drawn through the dies of four different kinds, all of which had been purchased from the ordinary suppliers. Soap and lime water was used as a lubricant, the drawing area reduction being 75-90%. And he made cleared that the measured values of drawing forces well coincided with the calculated values, if the latter were calculated by assumed values of frictional coefficients which were inclined to decrease according to the increase of the normal pressure acting between die-wall and material.