Influence of sand-sodium-silicate molds structured by steam-microwave solidification on castings surface burn-in and roughness

Abstract

The purpose of this work is to study the effect of sand-liquid glass molds, structured by the method of steam-microwave hardening (SMH-process), on the burn-in and roughness of the casting. The studies used molds prepared by the Cold-boxamin-process, Resol-CO2-process, CO2-process and SMH-process, which were filled with 30L steel. Samples of castings were cast in molds made by the SMH-process from steels 30L, 20Kh27N18S2L, gray cast iron SCh20, bronzes BrA9Zh3L, BrO5Ts5S5, BrO4Ts4S17, and aluminum alloy AL2. Overheating of all alloys above the liquidus temperature was 120 ± 7 °C. The microstructure of 30L steel samples was investigated using an MBS-10 optical microscope before and after their etching castings made in shell molds. Considering that the SMH-process is environmentally safer than the Coldbox-amin, Resol-CO2, more efficient and economical than the Cold-box-amin, Resol-CO2, CO2-process, then this method of making molds and cores, from among of the above methods, is the most promising for the manufacture of medium and small castings for general machine-building purposes from iron-carbon and low-melting non-ferrous alloys.
Proceeding from the foregoing, prospective studies should be aimed at establishing the regularities of the influence of a number of basic parameters of clad liquid glass mixtures and the conditions for the manufacture of molds and cores by the SMH method on the quality of casting and optimization of the conditions for structuring such mixtures in the conditions of casting production in modern foundries.