A New Universal Workability Criterion to Predict The Internal and External Ductile Failure in Cold Heading Process
Abstract - The occurrence of internal and external ductile failure in cold-headed products presents a significant obstacle in the fast-expanding cold heading (CH) industry. The presence of these types of ductile failure in cold-headed products may lead to catastrophic fractures under tensile loads even though the ductile nature of the material. Hence, several workability criteria were presented in the literature to predict each of the two failure types independently.
This paper presents the comprehensive experimental, metallurgical, and finite element simulation study of the internal and external ductile failure of the cold heading process (CHP) of 1038 steel. The outcomes of this study uncovered a new universal workability criterion that is suitable to predict internal and external ductile failures. The new workability criterion uses the stress triaxiality history as a damage parameter to accurately indicate the locus of initiation of the internal and external failures.
Implementing the new universal criterion in the cold heading processes stages design will be a powerful tool to produce high-quality cold-headed products.
Keywords - Adiabatic shear band, Cold heading, Cracks, Ductile failure, Workability criterion.