Articles

ANALYSIS OF FIBERS' BEHAVIOUR BEFORE/AFTER CASTING

2nd International Conference ICRF 2014

INTRODUCTION

During the cooling and solidification of castings in foundry or ingots in steel plant, the metal shows a certain volume reduction called "shrinkage".

To avoid shrinkage porosities it is necessary to supply additional molten metal contained into a special reservoir: the feeder head. To optimize feeding performances are commonly used chemical products called "feeding aids", such as special covering powders and linings for the feeding cavity walls, usually called "sleeves" or "feeder heads". After the cooling, when the metal shape is extracted, the linings are crumbled and workers can be exposed to the originated dusts. These linings are prefabricated products and every producer has its proprietary formulation; some of them contain Refractory Ceramic Fibers (RCFs), special wools with outstanding insulating properties, that have been included even into a list of substances at very high concern due to their carcinogenicity. On the other hand, other formulations may contain different fibrous materials such as mineral wools (MW) that are chemically different and represent a health-friendly alternative to RCFs.  

Through in-field trials, the possibility to achieve satisfactory solutions by RCF-free products was investigated. The morphological and the chemical transformations occurring in these products after the exposure to molten steel during the casting operations were also investigated through the comparison between the products before and after the casting. Comparisons with RCF-containing products were also performed. The obtained results highlighted that the replacement of traditional products containing ceramic fibers with RCF-free alternatives guarantees the same metallurgical quality of the products with a significant improvement of the health that can be assured in the workplace.

KEYWORDS

Refractory Ceramic Fibers, Carcinogenic, Foundry Aids, Lining, Riser, Feeder, Sleeve, Ingot, Casting.