Although this article started with a general overview of the iron and steel industry, we will refer only to one process for the rest of this feature, a gray iron foundry using an electric arc furnace. We will see how important brick and refractory are and why everyone should pay attention to their brick and refractory designs and installations.History and Background of the Electric Arc FurnaceThe electric arc furnace (EAF) has been around since the early 1900s and is primarily used to produce high quality alloy steels. EAFs have refractory-lined steel shells and vary ill size from only a few feet in diameter to twenty feet or more. The bottom, or hearth, of the furnace is dished to hold the metal charge. The vertical side walls include one or more doors and a tapping spout for removing the melted charge. The roof over the furnace is dome-shaped, and incorporates two or three openings near its center for the admission of electrodes into the furnace. The roof is usually detachable and is lifted off or turned aside for charging. The whole furnace structure is tilted forward and backward for slag skimming or tapping. The furnace capacity will depend upon the size of the furnace and can be less then one ton per charge to up to eighty-five tons per charge.

Shielded-Metal-Arc Welding (SMAW, STICK)AWS (American Welding Society) A5 specifications Set standards for electronics for SMAW of carbon, stainless, and low alloy steels; aluminum copper, and nickel and their alloys and weld-surfacing. Designations for covered electrodes carry the prefix ''E''. Packaged to AWS specifications, electrodes come in boxes, cans, or other containers, labeled with their AWS specification and trade name, quality control (heat or lot) number, supplier name, diameter and length, and weight of contents. Specifications require that every electrode bc marked for identification near with its numeric designation the grip end.To select a covered SMAW electrode, consider these factors, in approximate order of importance.

Thermal Structures has nearly 250 materials, mostly ceramic-based in its system. Outer covers are mostly 300 series stainless, with an increasing interest in both Inconel for higher temperature applications and aluminum for lower temperature uses."Sometimes there is a preconceived notion that the metal cover is the blanket," Buckett said. "The real key is the insulation under the metal cover. The idea, if we''re in the loop early enough, is to select the right materials and develop a noise or heat blanket for the specific application."

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