Effect of Processing Conditions on Mechanical Properties of a Ti Interstitial Free Steel

M.A. VICENTE ALVAREZ; T. PEREZ; F. ACTIS; P. SERÉ; G. CERVELLINI

STEEL RESEARCH

Verlag Stahleisen

Lugar: Osnabrück, Alemania; Año: 2004 vol. 75 p. 411 - 418

0177-4832

The effect of thermal cycle, cold reduction and temper rolling on texture, microstructure and mechanical properties of a Ti-added IF steel is presented. Sheets with different cold reductions were annealed using cycles with temperatures, heating rates and soaking times including extreme annealing conditions like continuous and batch regimes. Microstructure is characterized by equiaxed grains of about 17 to 20µm, being independent of the annealing cycle applied. As a function of the processing variables, texture depended mainly on heating rate and cold reduction degree, showing little dependence on soaking time or temperature. Despite the great differences between batch and continuous annealing cycles, yield strength, ultimate tensile strength and hardening coefficient n show little variation between these extreme regimes. This characteristic makes this steel almost insensitive to annealing conditions, strongly differing from other deep drawing materials like Al-killed steels. The influence of texture on r-value was studied using a Taylor-based model which showed good agreement with experimental relationships. Finally, temper rolling of annealed materials was simulated with elongations varying from 0.5 to 7%. This resulted in an important increase of YS and a decrease of n, but had a deleterious effect on strechability.