Use of Cores with Inorganic Binder to Produce Thin-Walled Nodular Iron Castings

One of the primary issues in foundries is the emission of components that arise from the pyrolysis of organic substances during the pouring phase. This issue is particularly relevant in ferrous foundries. For this reason, the European Community has promoted the project Green Casting LIFE 21-ENV-FI-101074439, which aims at the industrial-scale implementation of the use of inorganic binders for the production of cast iron or steel castings. The work described in this paper shows that producing thin-walled castings in SIMO cast iron (a type of nodular cast iron characterized by high silicon and molybdenum content) using sand cores made with inorganic binders is possible, thanks to a new generation of products. In particular, the study is centered on an analysis of the results obtained from four tests conducted in a ferrous foundry with the aim of evaluating the feasibility of using inorganic cores in the production of exhaust manifolds for the truck sector. These experiments highlighted that, even when used at temperatures above 1400 ºC, inorganic binders can guarantee satisfactory results in terms of the mechanical and technological properties of the cores, especially during the de-coring phase of the castings. Indeed, the castings obtained presented a quality that is comparable with those produced using other traditional technologies; this could represent a valuable opportunity for ferrous foundries interested in resolving or mitigating the problem of odors and pollution reduction; moreover, it confirms that inorganic binders, indicated as BAT (Best Available Technology) in the BREF Final Draft (released in February 2024), can be used to manufacture cores intended for the green sand molding process in cast iron foundries.