Evolution of Residual Micro Phase and Orientation Dependent Stresses during Cold Wire Drawing

Abstract

The residual grain and phase microstress evolutions in the ferrite matrix of pearlitic wires after several steps of cold wire drawing have been studied. Energy dispersive synchrotron diffraction revealed a significant divergence in the grain microstress evolution among differently oriented ferrite grains in the high deformation regime beyond accumulated true strain level εt ≥ 2.3.The possible physical reason for the observed divergence is discussed in terms of distinct microstructure development in this stage of the cold wire drawing.

Synchrotron Diffraction Study of the Cementite Phase in Cold Drawn Pearlitic Steel Wires

“…The residual stress in the axial direction increases up to 3.3 GPa at a true drawing strain of 1.6 and then drops and saturates at 1.8 GPa. The saturation of the cementite residual stress corresponds to a change in regime observed in the ferrite stress reported elsewhere [14]. The strain at which this happens also seems to coincide with the completion of the ferrite texture and lamellae rotation.…”

“…From these peaks the ferrite residual stresses and peak broadening could be obtained. The results are discussed in two separate contributions to these proceedings by M. Kriška et al [14] and M. Seefeldt et al [16], respectively.…”

“…Next to the measured residual stress, special attention will be paid to the possible existence of a cementite texture and cementite peak broadening. The main concern of the experiment were the residual stresses in the ferrite phase [14]. The quality of the data obtained on the cementite phase is therefore not entirely satisfactory.…”