SEDL / STP / STP987-EB / STP26240S

The Ladle Refining Process for Bearing-Quality Steels

Odar, JA
Supervisor of product metallurgists and supervisor of process metallurgists, LTV Steel Bar Company, Canton, OH

Fecich, DJ
Supervisor of product metallurgists and supervisor of process metallurgists, LTV Steel Bar Company, Canton, OH

Pages: 15    Published: Jan 1988

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Abstract

Bearing-quality steels that have been previously refined by the vacuum degas carbon deoxidation process for microcleanliness considerations are now able to achieve lower levels of oxygen and inclusion content by ladle refining. Through aluminum deoxidation in the presence of strong stirring energy, inclusions are removed by mechanical rather than chemical means. Such refining techniques are provided by ladle reheat capability, slag control, de-slagging, stirring, alloy and deoxidizer injection, and vacuum degassing, further enhanced with bottom pouring, shrouding, and casting.

Several ladle refining options were studied to evaluate the relative cleanliness levels that the processes were capable of producing. Superior levels of steel quality and chemistry control were achieved by these out-of-the furnace techniques in terms of microcleanliness as measured by the JK-worst field and SAM ratings, and of macrocleanliness as measured by magnetic particle inspection procedures of AMS 2301.