The third generation of advanced high-strength steels (AHSS) brought attention to the steel and automotive industries due to its good compromise between formability and production costs. This work evaluated a third-generation AHSS (USS CR980XG3^TM) through microstructural and X-ray diffraction (XRD) analyses, uniaxial tensile and plane-strain tension testing, and numerical simulations. The damage behavior of this steel is described with the Gurson–Tvergaard–Needleman (GTN) model using an identification procedure based on the uniaxial tensile and initial microvoids data. The microstructure of the CR980XG3^TM steel is composed of ferrite, martensite–austenite islands, and retained austenite with a volume fraction of 12.2%. The global formability of the CR980XG3^TM steel, namely the product of the uniaxial tensile strength and total elongation values, is 24.3 GPa%. The Lankford coefficient shows a weak initial plastic anisotropy of the CR980XG3^TM steel with the in-plane anisotropy close to zero (−0.079) and the normal anisotropy close to unity (0.917). The identified GTN parameters for the CR980XG3^TM steel provided a good forecast for the limit strains defined according to ISO 12004-2 standard from the uniaxial tensile and plane-strain tension data.

The material characterization regarding sheet metal formability is usually assessed by the forming limit curve (FLC). The FLC requires specialized and expensive equipment, several samples with different geometries, and can be a very time-consuming procedure for data treatment. Alternatively, the hole expansion test (HET) and the Erichsen Cupping Test (ECT) can be used for routine evaluations of sheet metal mechanical behavior. These formability tests require fewer quantities of material and easy specimen preparation with a fast analysis of results. The HET and ECT procedures provide a proper evaluation of sheet material stretch-flangeability, formability, strength, and ductility. In this work, we developed a low-cost mechanical device capable of performing the HET and ECT tests using a universal testing machine. The equipment is designed to meet the test parameters set by ISO 16630 (HET) and ISO 20482 (ECT) standards. In order to verify its functionality, tests were carried out with the dual-phase steels DP600 and DP780. The corresponding values determined for the hole expansion ratio and the Erichsen index provided reliable results in terms of the accuracy and repeatability of the proposed testing device.

To meet the demands of vehicular safety and greenhouse gas emission reduction, the automotive industry is increasingly using advanced high strength steels (AHSS) in the production of the components. With the development of the new generation of AHSS, it is essential to study their behavior towards manufacturing processes used in the automotive industry. For this purpose, the welding capability of newly developed third-generation Gen3 980T steel was investigated using the Nd:YAG (Neodymium:Yittrium Aluminum Garnet) laser-welding with different parameter conditions. The analysis was made by uniaxial tensile tests, micro-hardness, Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The criteria used to evaluate the quality of the weld were the distance between the fracture and the weld bead and the surface finish. A relationship between the quality of the weld and the energy density was observed, expressed by a partial penetration for values below the optimal, and by irregularities in the weld bead and a high number of spatters for the values above the optimal.

This work aimed to analyze the damage behavior of cold rolled TRIP780 steel sheet submitted to interrupted uniaxial tensile tests performed along the rolling direction. The formation of voids is investigated as a function of the straining level using digital image analysis of scanning electron micrographs to obtain the measures of void density, void area fraction, void aspect ratio and mean void size. The volume fractions of both ferrite/martensite and retained austenite constituents were obtained from X-ray diffraction measurements. An abruptly decrease of retained austenite was observed at early stages of deformation followed by a slow saturation. The resulting strain-induced martensite is responsible for improving the formability of the TRIP780 as observed by instantaneous strain-hardening exponent. In the lower strain range, growth and coalescence of existing microvoids prevailed at both in-plane directions whereas nucleation of microvoids was also observed along the loading direction. Conversely, nucleation prevailed at the transverse direction in the intermediate strain range whereas growth and coalescence were predominant aligned to the loading direction. At larger strain levels, growth and coalescence of microvoids prevailed at both directions. The microvoids were initially found around inclusions and at the interface of ferrite-martensite phases and lastly also at the ferrite matrix.

This study presents a combined experimental–numerical methodology to calibrate the mechanical behavior of an advanced high-strength steel (AHSS) with transformation-induced plasticity (TRIP) effects, incorporating both initial plastic anisotropy and ductile damage. The investigated TRIP 780 grade, widely used in the automotive industry for its exceptional strength–ductility balance, exhibits a complex deformation response that demands accurate constitutive modeling for reliable sheet metal forming simulations. The methodology minimizes the number of required specimen geometries without compromising accuracy. Three flat-sheet specimens were employed: standard uniaxial tension (UT) and two double-notched designs reproducing intermediate (ID) and plane strain (PS) modes. Experiments combined digital image correlation with finite element analysis. Hill’s 48 quadratic yield criterion captured the initial anisotropy of the TRIP 780 sheet, while the parameters of a phenomenological ductile damage model were calibrated from the experimental data. The TRIP effect under UT was quantified by X-ray diffraction, showing a decrease in retained austenite from 9.9% (as-received) to 3.2% at 21% equivalent plastic strain. Fractography revealed damage initiation dominated by void nucleation at phase boundaries. The proposed approach yielded stress–strain predictions with R² values exceeding 0.99. This simplified approach offers a cost-effective and experimentally feasible framework for constitutive modeling of AHSS grades, enabling practical applications in advanced sheet forming simulations.