The melting cycle is a dynamic process in which clean charge materials lead to byproducts that can reduce the metallurgical quality of the iron produced, unless an effective treatment is applied. Previous articles in this series have pointed out and hopefully will lead to the understanding that iron oxide supplies the harmful free-oxygen atoms so harmful to iron-melting processes. Iron oxide is produced during the cupola melting cycle. It is not contained in the metallic […]

Stopping molten iron oxidation is the first priority for foundries operating cupola systems. The next step is to initiate the system and melting process changes that will improve iron quality and productivity. Cupola melting cannot be optimized until the melting process has been deoxidized. Molten iron oxidation occurs naturally in cupola melting: It cannot be prevented but it can be countered – offset. Previous reports in this series described the methods and an only-recently-available deoxidation […]

A cupola’s thermal efficiency determines how effectively sensible heat is directed to the molten iron, and how much is wasted. Maximizing thermal efficiency requires the cupola operator to understand the critical design details. Previous entries in this series examined the roles iron oxide and free-oxygen atoms for cupola melting processes. Both of these are important factors for foundries seeking to maximize cupola operation. Assuming iron-oxide formation within the cupola has been addressed and countered, the […]

There are several steps to maximizing cupola operating performance, but the first and most important is to manage the detrimental influences of iron oxide. Iron oxide threatens all iron-melting processes. In cupola melting, much greater amounts of iron oxide are produced during the normal melt cycle than are produced in electric furnace melting. This makes iron oxide’s effect much more pronounced in cupola melting. In EF melting, 20%-30% oxidation loss is the extreme of losses […]

The challenge of metal oxidation is magnified in cupola furnaces because iron oxides are produced in greater volumes. The melting cycle needs to be examined to pinpoint exactly how oxidation losses occur, and how they can be overcome. Iron melting operations face the same challenge with electric furnaces and cupola furnaces — molten metal oxidation. Oxidation is caused by molten iron’s contact with the atmosphere. Last year in these pages we addressed in detail the […]

Clean, quality molten metal should be the goal of every ferrous foundry, and the technology is available to achieve it — but the results depend on you. The development of high-quality iron castings begins with melting processes and techniques. You control how it is melted, giving you the final call in determining its quality. Everything depends on you. Molten iron contains desirable and undesirable elements. In a ferrous foundry, you control both of these. From […]

Chemical treatment technology is making it possible to extend the service life of a furnace lining — while improving the quality of the iron produced. Refractory erosion in iron melting is seldom attributable to mechanical wear. Erosion generally is the aftermath of slag’s chemical attack – chemical reactions between slag and refractory – producing reaction byproducts that enter the slag. The overall effect is refractory’s effective protection layer, the thickness of the refractory lining, is […]

The chemical process that leads to surface defects, inclusions, pinholes, slag, dross, and misruns is continuous and ongoing. The only way to stop it is to cut off the supply of free oxygen atoms. Steel producers have long recognized the role that free oxygen atoms play in the formation of defects in their finished products. Appliance-grade steels, deep-draw can steels, and many other grades cannot tolerate surface blemishes or defects. Steel industry metallurgists determined the […]

Using metal cleanliness to prejudge molten iron’s fluidity is a breakthrough technology. It substantially reduces the risk for scrapped castings. The ingredients of a furnace charge, whether it is an electric furnace or a cupola melter, are formulated to produce the final chemistry required for the castings to be poured. Unfortunately, formulating the charge does not determine the final chemistry or quality of the molten iron. Melting is not simply the process of re-melting existing […]

Iron foundries must address and eliminate the effects of oxidation by controlling FeO in slag contacting the molten metal. Carbon and silicon oxidation losses always occur in iron melting. The losses are costly, but they can be prevented easily with newly available technology. Free-oxygen atoms present in the molten iron cause oxidation: These unwanted atoms are supplied by iron-oxide molecules contacting the molten metal surface. Oxygen atoms cannot be “removed” effectively from molten iron. Nothing […]