MICROSTRUCTURAL EVOLUTION IN SEVERELY DRAWN HIGH CARBON CONTENT WIRES

M. AVALOS; M. ROMANYUK; E. BRANDALEZE

Cancun

Congreso; XXVII INTERNATIONAL MATERIALS RESEARCH CONGRESS; 2018

International Material Research Society

SeverePlastic Deformation can induce nanometric grain sizes, phase distributions and defectstorage that cannot be achieved by any other means. Their microstructures are responsiblefor mechanical property improvements which have not been fully exploited yetexcept for a few cases. High carbon content steels subject to large wiredrawing deformation, and later on bundled together forming conforming largesection cables, are one of the few products of extensive large scaleapplication. They develop high strength (5-6 GPa) and large ductility, making themparticularly useful for applications such as cables for bridges and heavycranes. The technology is well known but the complex interaction between deformationmechanisms, microstructure development and precipitates due to the high carboncontent (~0.84%) has not been completely clarified. Clarification of thosemechanisms in such successful product may shed light on modern SPD processes.In thiswork we present EBSD results in high carbon content wires of several diameters(8 mm, 7 mm, 3.2 mm, 2.8 mm, 2 mm). Optical and EBSD microscopy, together withXRD, were used to characterize textures, microtextures and microstructureevolution. Differential Thermal Analysis (DTA) and thermodynamic simulations(FactSage) were used to characterize their thermal responses. InversePole Figure maps, misorientation distribution parameters (KAM, GAM, GOS, GND,etc.) and other post-processing tools are used for characterizing the evolutionof the microstructure. Some other test like micro-hardness and mechanicaltorsion tests were correlated with the microstructure evolution. Despite beingsubject to room temperature deformation, the severity promotes several dynamicrecrystalization and strain aging mechanisms like cementite destabilization andcarbon diffusion with a consequent increase on the material strength [1,2]