BETHLEHEM, PA, May 16, 1997 - Bethlehem Steel Corporation has received a U.S. patent for the development of a sensing device that accurately determines the carbon content of low-carbon steels manufactured in a basic oxygen furnace (BOF). The Bethlehem method is accurate to within a margin of error of 0.004% C.
Low carbon steel is widely used to manufacture finished steel products because of its good formability properties. In the automobile industry, for example, low carbon steel permits manufacturers to stamp and form complex automotive shapes without encountering spring-back after the forming operations.
For this reason, it is critical for steelmakers to be able to accurately manage and control carbon levels in steel to insure that low-carbon metallurgical requirements are met.
The Bethlehem method involves the use of a light intensity sensor housed within a temperature regulated case which has a sighting window equipped with a unique air wipe that shields the light sensor from steelmaking dust and fume. The sensor controls or determines the carbon content of a BOF heat by measuring a difference in visible light intensity emitted from the mouth of the BOF vessel in relation to the amount of oxygen blown into the vessel, from a point of maximum light intensity to the end of the oxygen blow.
With the Bethlehem sensor, the light intensity and oxygen readings are used to compute continuous, real time in-blow percent carbon levels until an aim carbon content is reached for the heat.
The air wipe encircles the light sensitive portion of the sensor to shield it from the dust and fume that erupts from the mouth of the vessel, and maintains the sensor at a constant temperature level. The result is an accurate method for determining and controlling the carbon content in the steel bath.
The Bethlehem patent, which recognizes Alok Sharan, a research engineer at Bethlehem's Homer Research Laboratories, as the inventor, has received U.S. Patent No. 5,603,746.
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