Predicting Binder Decomposition and Core Gases

May 7, 2019
Joint development for validated data on quantitative prediction of process-relevant effects

MAGMA GmbH is pooling efforts with ASK Chemicals GmbH to develop a material database on binder decomposition in sand cores and associated gas formation.

MAGMA develops casting process simulation programs, while ASK develops foundry chemicals and consumables, including sand binders and coatings. The joint effort is aimed at providing MAGMASOFT® software users with validated data on quantitative prediction of process-relevant effects for ASK products.

Specifically, MAGMA and ASK expect to offer their customers the basis for interpreting the venting behavior of sand cores and predicting core gas-related casting defects.

"With the possibility to predict the behavior of our products with any core geometries during casting, we can support our customers in a more targeted manner. Comprehensive customer service therefore already has the highest priority for us in the planning stage of production processes," stated Jörg Brotzki, executive vice president, Europe at ASK Chemicals.

During metalcasting, gases form and expand in cores and molds as binder components and other volatile constituents decompose. This is closely related to the choice of basic sand binder mixture and its compaction, as well as its specific gas permeability. Different volumes of gas are produced at different times, depending on the type and quantity of the volatile components, the thermal exposure, and the respective decomposition behavior.

Relatively high gas pressures at the interface to the melt can result in gas inclusions in the casting. In the cases of complex cores, or even core packages, it is difficult in practice to determine if core gases are the cause of defects due to the numerous and diverse influencing factors.

New simulation models in MAGMASOFT virtually depict gas formation, gas flow, and venting through core prints or the penetration into the melt, so it’s possible to predict the risk of defects due to gases from cores and molds.

The two partners have agreed on the collaboration as part of a development project to quantify the decomposition behavior and gas formation of different ASK binder systems. In its laboratories and Technical Center, ASK Chemicals will research the decomposition effects with different binders. Respective laws of decomposition behavior and resulting gas formation will be quantitatively determined for different binder systems and heating characteristics.

Product-dependent kinetic models will be derived from these data that will make the formation of gas volumes and the resulting effects in MAGMASOFT quantitatively predictable.

While the partners note their collaboration is designed as a long-term effort, they will present the first results of the joint development at GIFA 2019, in Düsseldorf, Germany.

"The possibility of systematically avoiding core gas-related casting defects through quantitative consideration of different ASK binder systems already at the project planning stage represents a significant benefit for our customers," according to Dr.-Ing. Jörg C. Sturm, managing director of MAGMA GmbH.