Effect of Deformation Heat Treatment on the Structure of Two-Phase Steel in a Bimetal Composite and its Mechanical Properties

Features are revealed for the inheritance of bimetallic rolled product of dendrite inhomogeneity of the cast structure of two-phase austenite-ferrite steel applied in the form of a cladding layer on a base of low-alloy steel. It is shown that the banded and fiber structure of a cladding layer on rolled product is the result of retention of chemical liquation and rebuilding of the surfacing dendritic structure. Results are given for quantitative analysis of specimen fractures tested in static tension in the form of two parameters, i.e., work for plastic deformation localization and specific area of a fracture surface characterizing the energy content of failure. Areas of the surface of all fractures having a complex configuration are determined with considerable accuracy due to the original procedure of digital measurement of a three-dimensional failure surface from results of photogrammetric exposure on a meso-macro-scale followed by recreation of a complete three-dimensional model of the relief. Quantitative properties of fractures are supplemented by the strength and ductility indices of bimetallic rolled product, which makes it possible to substantiate the optimum version of final heat treatment and material use taking account of carbon content in the main layer.