ACTUAL ISSUE 4/2015

/// 02
Orlenius, J.; Gotthardsson, U.; Diószegi, A. Mould and core gas evolution in grey iron castings

The volume and rate of gas evolution from cores prepared with various binders and sand has been determined with a new commercial technique. Spherical cores were mounted on a glass tube and immersed into molten grey iron. The gas generated by decomposition of the binder was determined by displacement of water in a measuring tube placed on a balance. The gas evolution from PUCB, epoxy and sodium silicate cores changes insignificantly during the first week after production. Neither influences iron temperature the amount of evolved gas to a large extent. Different binders evolve different amount of gas, but also the sand type affects the gas evolution. The impact of additives on the gas evolution is dependent on the amount of organic compounds in the additive. Coatings increase the total gas volume, while the maximal rate is not necessarily affected. Dried green sand evolves more gas than chemical bonded sand.     Di Muoio, G. L.; Tiedje, N. S. When dry is dry? Process design rules, simulations and industrial cases on the drying of water based foundry coatings Drying of foundry coatings is a relatively new process in the foundry industry that has come into use with the introduction of water as a solvent for mould coatings. In this paper we present an overview of the results of several tests and simulations carried out recently at Global Castings A/S, Copenhagen, Denmark, and at the Technical University of Denmark, Copenhagen, Denmark, on the drying of water based foundry coatings. In particular, we focus on the critical parameters and properties to be controlled in order to achieve a stable drying process. We propose for each of these parameters simple methods for testing both at laboratory and production scale so that material characterization and model validation can be carried out also for materials different from the ones considered in this study. Finally, we present the application of a simple calculation method and more advanced simulation tools, on real industrial cases. These tools have been developed in order to simulate the drying process and reduce design time and cost of expensive drying equipment.




››› 
www.giesserei-verlag.de
››› Order magazine
   HOME    IMPRINT    © GIESSEREIVERLAG GMBH 2011