Abstract
This study concerned the response of medium carbon steels microalloyed with vanadium and titanium, to deformation in intermediate ("warm") temperature zone. Titanium varies from 0.003 to 0.039% in weight.
A critical automotive component (the constant velocity universal joint) warm-forged has been studied by means of a hot torsion simulation technique. Besides its warm-ductility, the influence of the heating temperature before "warm" forging, the "warm" deformation temperature and the weight percentage of Ti on the final steel properties (grain size, microstructure and hardness), was determined.
It was found that the optimal ductility is reached between 750 and 775°C and that the best characteristics (smallest grain size and highest hardness) are obtained with a Ti weight percentage of 0.019% and at lower deformation temperatures (from 700 to 750°C). Hence, the automotive component might be warm-forged close to 770°C in order to obtain the best mechanical characteristics with enough warm-ductility to avoid warm-forging problems.
