A new method for fast microstructure analysis of heavily deformed ferritic–pearlitic (F–P) steels has been developed based on X‐ray diffraction (XRD). The method provides information about residual stresses and microstructure defects occurring within the material volume and therefore allows reliable estimation of strength properties. Besides, significant reduction of testing time can be achieved compared to conventional investigation methods. Development and testing of “fast microstructure analysis” was done by means of experimental simulation of wire and rod production process including hot rolling, wire drawing, and heat treatment of steel C45 with ferrite/pearlite microstructure. It was found that the dominant structure defects driving the ultimate tensile strength of F–P steel in case of hot‐rolled and heated steel are the misfit dislocations in pearlite, while in the cold‐drawn wires, it is the residual stress borne by the cementite lamellas.

Abstract.A new method for a fast analysis of heavily deformed, multicomponent ferritic/pearlitic steels microstructure based on XRD measurements had been developed. Its practical application has been examined and proven during wire rod production of a high-strength eutectoid non-alloyed steel grade containing 0.81 weight percent carbon. For individual technological conditions, the lattice strains and their anisotropy were analysed quantitatively by means of fast X-ray diffraction measurements and correlated with the results of comprehensive mechanical testing. Obtained relationships between the microstructure characteristics and mechanical properties were described using physically based models and used to establish a material specific database for prediction of the mechanical properties from X-ray diffraction data. Depending on the deformation state different parameters have to be applied for the material's macroscopic properties prediction. Additionally, the fast microstructure analysis can provide more detailed information in the case of deviations from the as-required material's properties due to technological aberrations.