EXTRUSION OF 01417 ALLOY INGOTS OBTAINED IN THE ELECTROMAGNETIC CRYSTALLIZER AT THE CONFORM UNIT

Abstract

It is known that casting long ingots of small sections (∅8–12 mm) of 01417 alloy into an electromagnetic crystallizer makes it possible to obtain a dispersed structure with insignificant intradendritic segregation. Diffusion annealing of ingots (550 °C, 4–5 h holding time) eliminates intracrystalline segregation and reduces the level of internal stresses in metal thus providing the conditions for subsequent wire drawing. The paper demonstrates that high plastic deformation of ingots without diffusion annealing can be achieved by Conform continuous extrusion, which ensures high quality and geometrical accuracy of products. The analysis of various Conform units revealed an inherent weakness – the absence of connection between the system securing the fixed part of the detachable container (shoe) and the drive wheel shaft, which leads to an increased load in the operating mode. The purpose of the work was to upgrade the Conform unit by creating a connection between the shoe and the impeller shaft to obtain a high-quality billet for subsequent wire drawing of the ∅12 mm ingot cast into the electromagnetic crystallizer. An optimal temperature of ingot extrusion (300 °С) was found to eliminate the intense adhesion of wrought metal on the tool surface. The experimental ∅5 mm rod made of 01417 alloy obtained from the ∅12 mm ingot at the Conform unit features high processing ductility. This is indicated by an increase in its yield point and relative elongation. Metallographic studies demonstrated a fine-grained structure achieved in the extruded rod, which provides the conditions for subsequent wire drawing without annealing. The results of the study provide a basis for refining the process conditions of calibrated billet production on the Conform unit followed by wire drawing with required properties.