An Investigation of the Plug Drawing Process

Abstract

The object of this work has been to obtain agreement between the existing theory of tube drawing with a plug, and experimental results, and thus to be able to predict the behaviour of the metal when conditions of drawing are altered. As the basis of theoretical study Sachs's approximate theory has been chosen, and mild steel containing 012 per cent carbon has been used as the test material.

The use of the theory requires the knowledge of the true mean yield stress of the metal undergoing plastic deformation, as well as that of the value of the coefficient of friction. The method of establishing those two quantities is discussed in detail. Drawing stresses are calculated and it is shown that close overall agreement exists between theory and practice and that, therefore, the mathematical formulae can be used with confidence. The components of the total work done in drawing a tube are determined and discussed, and the adverse effect of sink on the magnitude of redundant work is indicated.

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