Largest bell in foundry

Collection of 53 bells cast by the J.H. Taylor Bell Foundry of Loughborough, England. Largest or Bourdon bell weighs more than 12 tons and has the pitch of E-flat below middle C. The smallest weighs 12 pounds and sounds G-sharp, four and 1/2 octaves above the Bourdon. (source: Encyclopedic Survey, p.1123)

As-cast morphology of iron-intermetallics in Al-Si foundry alloys

The as-cast three-dimensional morphologies of alpha-Al-15(Fe,Mn)(3)Si-2 and beta-Al5FeSi intermetallics were investigated by serial sectioning. Large beta-Al5FeSi intermetallics were observed to grow around pre-existing dendrite arms. The alpha-Al-15(Fe,Mn)(3)Si-2 intermetallic particle was observed to have a central polyhedral particle and an external highly convoluted three-dimensional structure. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Combining Sr and Na additions in hypoeutectic Al-Si foundry alloys

From recent published data, it is still unclear whether combining additions of Na and Sr have synergistic effects or deleterious interactions, This paper clarifies the interactions between these two modifiers and investigates the effects of such interactions on alloy solidification and castability. It was found that combined additions of Sr and Na do not appear to cause improvement of the modification of the eutectic microstructure even after only a short period after addition. Na addition may promote Sr vaporization and/or oxidation kinetically. leading to a quicker loss of both modifiers, which is blamed for the rapid loss of the modification effect during melt holding. Quenching trials during the eutectic arrest indicate that addition of Sr into Na-modified melts does not alter the eutectic solidification behaviour The effect of Na on eutectic solidification dominates, and the eutectic is observed to evolve with a significant dependency on the thermal gradient, Combining Sr and Na additions produced no beneficial effects on porosity and casting defects. (c) 2005 Elsevier B.V. All rights reserved.

Iron-related porosity in Al-Si-(Cu) foundry alloys

An experimental program has been undertaken to explore the effect of iron concentration on porosity levels in Al-Si alloy sand castings. The effect of iron concentrations above, below and equal to the critical iron content for alloys with either 5 or 9% Si and either 0, 1 or 3% Cu has been determined. Increasing iron concentrations were found to increase porosity in all alloys except the copper-containing Al-5% Si alloys which displayed a porosity minimum at the critical iron content. Porosity was observed to be higher in the Al-9% Si castings than the Al-5% Si castings. Differences in the primary phase volume fraction and morphology may explain this observation. The results of this experimental work do not support the existing published theories that have been proposed to explain the effect the iron on porosity. An alternative theory is therefore developed. (c) 2006 Elsevier B.V. All rights reserved.

Effects of combined additions of Sr and AlTiB grain refiners in hypoeutectic Al-Si foundry alloys

Strontium is the most widely used and a very effective element for modifying the morphology of eutectic silicon, while Ti and B are commonly present in the commercial grain refiners used for Al-Si alloys. Systematic studies on the effects of combined additions of Sr and different AlTiB grain refiners on the Al + Si eutectic and primary aluminium solidification have been performed. While slight coarsening of both eutectic Si and primary aluminium grains occurs during holding, no obvious interactions are observed between Sr and AlTiB grain refiners when the addition level of grain refiners is low. As a result, a well-modified and grain refined structure was obtained. However, strong negative interactions between Sr and Al1.5Ti1.5B3 were observed as the addition level of the grain refiner increases. It was found that these interactions have a much more profound impact on the eutectic solidification than the primary Al solidification. The melt treated with combined additions of Sr and Al1.5Ti1.5B still shows good grain refinement efficiency even after losing its modification completely. The mechanism responsible for such negative interactions is further discussed. (c) 2006 Elsevier B.V. All rights reserved.

Recent advances in understanding the eutectic solidification in Al-Si foundry alloys

The formation of the Al-Si eutectic is generally the final stage of the solidification process of Al-Si foundry alloys. This means that it can be expected to have a significant impact on the feeding of a casting, and consequently the formation of casting defects, in particular porosity. Understanding and controlling the eutectic solidification process are therefore very important. This paper reviews the recent advances and unique techniques used in improving our understanding of both eutectic nucleation and growth. The role of different modifiers in controlling the eutectic solidification mechanisms is presented and the relationship between eutectic solidification mechanisms and porosity formation is outlined. This new approach to aluminium foundry alloy metallurgy is likely to form the basis for further optimisation of alloy performance and master alloys for the future.