That certain something in the casting process: New hybrid additive for more effectiveness and efficiency in casting production – ASK Chemicals

Missed out on an order again? The competitor tendered a cheaper bid again? Who hasn’t experienced that?

The major challenges in the foundry industry are pronounced cost pressure and strong competition for the technological leading-edge. This article provides an overview of how the use of hybrid additives can increase both effectiveness and efficiency in casting production.

Depending on the requirements, additives essentially do the following: they are used to reduce or avoid casting defects that usually result in rejects or rework. This is already common practice and can be regarded as standard procedure in the industry. In addition, new additive technologies open up the possibility to expand and re-evaluate casting technology limits. Experience shows that new hybrid additives can be an alternative to partially replace the coating process or to avoid deploying or replace expensive specialty sands.

Additive comparison

Classification of additives
The classification of additives is based on the origin of the material; namely organic, inorganic and hybrid additives.

Organic additives
This class generally consists of hardwood or plant extracts and is usually dosed at 0.5% to 5%. These additives are often used in the core production of cold-box processes in order to avoid sand expansion defects.

Inorganic additives
Inorganic additive ingredients include, for example, iron oxides, ceramics or minerals. As a rule, due to their composition, no gas development arises. Inorganic additives are particularly suitable for coating-free casting, but they require a high additive rate of 2% to 12% and result in high raw material costs.

Hybrid additives
A relatively new generation of additives are hybrid additives. They combine the advantages of the aforementioned additive systems. They are very effective against veining. They can also be used for coating-free casting. Hybrid additives of the latest generation are recommended to replace expensive specialty sands.

Hybrid additives for substitution of special sands
Specialty sands are natural mineral sands, sintered or melted products and mixtures thereof. The granular mould is produced, if necessary, through crushing, classification and screening processes or also through other physico-chemical processes. Specialty sands differ from quartz sand in particular due to their low thermal expansion behaviour in the temperature range from 20°C to 600°C. Foundries use specialty sands mainly due to the associated high efficiency against casting defects such as, e.g. veining or metal penetration. Specialty sands typically demonstrate little to no gas emissions. Before deploying specialty sands, an accurate cost assessment should be performed. Typical addition quantities of 30% to 100% as well as the factors of availability, reclamation, transport, storage and waste disposal clearly demonstrate the high cost of using these raw materials. Moreover, it has to be considered that specialty sands, like all natural products, are subject to quality fluctuations which can impair process reliability.

Improvement of the surface quality by using Veino Ultra 3010, half-coated

In contrast are the hybrid additives of the latest generation, such as Veino Ultra 3030. These products allow either to partially or completely abandon the use of cost-intensive specialty sands, resulting in the same or even better casting quality.

This is illustrated by two examples: Figure 2 shows the improvement of the surface quality and Figure 3 the possible material cost savings that can be achieved by using Veino Ultra.

New hybrid additives such as Veino Ultra 3030 are ideal for resolving casting defects and optimising casting quality. Comparing the cost of quartz sand in combination with Veino Ultra 3030 with the cost when using specialty sands, the moulding material mixture with additive demonstrates a significantly better cost-benefit ratio.

Material cost comparison at 10kg core weight (base: quartz sand)

By using new hybrid additives to substitute (completely or partially) expensive specialty sands, foundries have leverage to improve the overall cost-benefit ratio while maintaining or improving casting quality. In view of the steadily increasing competitive pressure, new hybrid additives represent a valuable gain for foundries, allowing them to generate additional competitive advantages.

ASK Chemicals Group completed the acquisition of the industrial resins business from SI Group (New York, USA), late in 2021. With this transaction, ASK Chemicals Group, headquartered in Hilden near Düsseldorf (Germany), strengthened its position as a global supplier of high-performance industrial resins.

ASK Chemicals purchased SI Group’s industrial resins business and associated manufacturing sites in Rio Claro (Brazil), Ranjangaon (India) and Johannesburg (South Africa), as well as licensed technology and concluded multiple tolling agreements worldwide.

Sources
[1] ASK Chemicals: Technical data sheet Veino Ultra 3010

This article was authored by Verena Sander, Manager Global Marketing Communications and Ismail Yilmaz, Technical Product Manager Additives and Coated Sands Europe. Veino Ultra and Veino Ultra 3030 are trademarks of ASK Chemicals

For further details contact ASK Chemicals on TEL: 087 057 7647 or visit www.ask-chemicals.com