Mechanical Properties and Structure of Castings upon Various Ladle Processes of Liquid and Crystallizing Steel

Abstract

This work discusses the influence of external impact upon pouring of high strength alloyed steel into thin walled molds with external cooling and in the same molds with suspension pouring: complex impact on hardened casting. Selection of these technologies is substantiated. The casting produced in a 3D liquid glass mold was used as reference. Microstructure, fracture, and mechanical proports of metal were analyzed at regular (+20°C) and higher (+350°C) temperatures. The most dense and homogeneous structure and fracture were obtained for the casting upon complex impact. It has been established that the main advantage of the proposed technologies is improvement of homogeneity of mechanical properties across the cross section and height of castings, especially of plastic properties and impact viscosity. Anisotropy of the properties across cross sections and height of experimental castings is significantly lower than in reference casting. It has been established that the external and complex impact on formed casting allows to improve its mechanical properties upon various test temperatures. The casting produced in a metal shell mold with forced cooling exhibits no significant differences of mechanical properties both across its heigh and cross section. Herewith, the strength is in average by 100 MPa higher than that of reference casting at the same high plasticity and impact viscosity.