金属薄板の深絞り性評価尺度について

概要

論文の詳細を見る
The plastic strain ratio in the uniaxial tension of a sheet metal, i. e., γ-value, has often been used as a material parameter which shows good correlation with the limiting drawing ratio (LDR). However, such a good correlation is not always observed for aluminium sheets whose γ-values are less than unity. Also, for half-hard and hard aluminium sheets, it is difficult to accurately measure the γ-value itself because of very small elongation to fracture. To overcome these problems in the estimation of drawability of sheet metals, in this paper, a new measure, the "Y-value", which is based on the stress state of a drawn cup has been proposed in place of the γ-value. This measure is expressed as the ratio of the flow stress at the punch profile portion to that at the flange portion. The experimental results of various sheet metals show that the LDR has better correlation with the Y-value than the γ-value. It is also confirmed that the X-value, which is the ratio of flow stress in balanced biaxial tension to that in uniaxial tension, can be used as a practical measure of estimating drawability of sheet metals.
一般社団法人日本機械学会の論文
1993-12-25