Fem Analysis of Effect of Die Angle on Strain and Stress State in Process of Drawing of Steel for Prestressed Concrete

A die angle is one of the most important parameters for a drawing process. It should be chosen in that way that a draw stress is low, a wire surface quality is satisfactory and die durability is high [1]. The temperature of a wire in deformation zone depends on amounts of heat generated during a drawing. This heat consists of two components; one is the work piece deformation and another is friction between the wire and the die. Especially, the amount of the heat from the friction work strongly depends on a die angle [2]. The main aim of this work is a computer simulation of the drawing process of high carbon steel wires for prestressed concrete a calculation of the temperature distribution in the deformation zone for different die angles, as well as an estimation of the effect of those angles on the distribution of stress and strain in a die. It should enable estimation of a possibility of occurring of the strain aging in drawn wires and explanation of dependence of mechanical properties of wires on a die angle. In the paper the results of a computer simulation of the drawing process of steel wires for a prestressed concrete have been presented with FEM software (Forge 2). Dies with a different die angle 2a = 8°, 12°and 18° were used in the drawing process of a DB92 steel wire rod with 5,5 mm in diameter (according to Polish Standards) in five passes for final wires with 2,5 mm in diameter. After every pass mechanical properties and draw stresses were determined.