Material Databases and Validation in Modelling the Structure of Castings Using the Cellular Automaton Method

The paper presents the scope of applicability and the usefulness of the method of predicting crystalline structure of castings using a commercially available system called Calcosoft CAFE. The influence of individual values of the parameters of the thermal model and the model predicting the structure (phenomenon of nucleation and crystal growth), and the method of interpretation of the results were identified. In simulation studies, it is important to use reliable and validated material database, under appropriate conditions. It is necessary to predict the properties of castings with a comprehensive, new and practical approach to modelling the formation of phase components of structure in terms of both macroscale and microscale phenomena (Multiscale and Multiphysics). Therefore, in this paper, the experimental-simulation validation of the CAFE code was undertaken. The tests were carried out on castings solidifying under various heat transfer conditions controlled by mould materials such as: a homogenous mould made of moulding sand, moulding sand with chill, and mould made of insulating mass with chill. These conditions directly influence the structure formation. The method of validation of the structure was determined in terms of its three parameters, i.e., the degree of refinement of the crystals, the location of the columnar-to-equiaxed transition zone—CET and the angle of the crystals. The above tests enabled to extend the content of databases, which often lack the necessary values of parameters used in modelling, e.g., crystallization of a specific alloy under given conditions (sand casting, chills or laser surface treatment). On this basis, the basics of correlating the simulation results on a micro- and macroscale were generalized, the limits of the application of individual parameters (mould, alloy materials) and their impact on the structure formation were determined. It resulted in the extension of the database for simulation calculations.

Determination of Mass Loss in Samples of Post-Regeneration Dust from Moulding Sands with and without PCL Subjected to Biodegradation Processes in a Water Environment

In recent years, the demand for products made of biodegradable or partially biodegradable materials has been increasing. This is mainly due to the ever-increasing amount of waste in landfills, but also to the problem of post-production waste management. This problem also concerns waste from the casting process of sands made on the basis of furfuryl resin, as well as residues from the regeneration process of these sands. The article presents the issues related to the methodology of research on the biodegradation process both in the natural environment and methods conducted in laboratory conditions. The preliminary results of the research on the biodegradation process in the aquatic environment, to which the dusts from mechanical regeneration of moulding sand were subjected, indicate the directions of further research and work in the field of selection of components of moulding sand with biodegradable properties. These tests should be carried out primarily in terms of determining the minimum and maximum amount of the addition of a biodegradable component to the moulding sand.

Investigation on the Influence of Different Additives on Properties of Green Sand Mould

Green sand mixtures which are used for moulding purposes in foundry industries should possess sufficient green compression strength, flowability, toughness and air-permeability. Usually, the aforementioned properties for a particular casting differ due to variation in composition of the moulding sand mixtures, sand grain shape and size, bonding capacity of the binder, type and quantity of additives used, etc. The present work focuses on the effect of various additives namely, camphor powder, coconut shell ash, mixture of camphor powder and coconut shell ash at diverse proportions on permeability and green compression strength of the sand moulds. The quantity of the aforementioned additives for experimentation was varied from 0.5 to 3.5 wt. %. It was found that the mould’s permeability increased on addition of 1 wt. % additives for all cases. Similarly, the optimum quantity of additives that needs to be added to the sand mixtures for enhancing green compression strength was found to be 2 wt. %. Among all the additives used for improving the mould’s permeability, substitution of camphor exhibited best results. The green compression strength was found to be highest for the coconut shell ash containing sand mould. The moulding sand containing a combination of camphor powder and coconut shell ash between 1 to 2 wt. % exhibited fine mould permeability along with sufficient green strength.