SYMPOSIA PAPER Published: 01 January 1993

Improved Properties of Bearing Steels by Advanced Metallurgical Processing


The completion of the EAF-Ladle Degassing (LD)-Ingot Casting (IC) route at TEW, Witten works, by a Ladle Furnace (LF) together with the aluminum predeoxidation instead of the formerly vacuum carbon deoxidation (VCD) results in further improved oxide cleanness values of through-hardening bearing steels expressed by decreased macro-inclusions and oxygen contents. In the BOF-RH-degassing-IC and CC route at Thyssen Stahl, Duisburg works, the replacement of RH-degassing by the newly installed (LD) also improves the steel cleanness. Contrary to continuous casting (CC), stream shrouding in uphill IC has only a marginal effect on steel cleanness. The use of high alumina trumpet and runner bricks in uphill IC instead of fire-clay materials also does not improve the cleanness of through-hardening bearing steels. The investigation of carbon segregation in as cast ingots and continuous casting of different shapes and sizes quantifies significant differences of segregation pattern and degree. However, after an appropriate high-temperature annealing before rolling or forging, the customer's specification of carbide size and distribution is well achieved. From the comparison of the reported results with regard to cleanness and segregation, it can be concluded that continuous casting should allow the same application as ingot casting.

Author Information

Baum, R
Thyssen Stahl AG, Witten, Germany
Böhnke, K
Thyssen Stahl AG, Witten, Germany
Otto, J
Thyssen Stahl AG, Witten, Germany
Pflipsen, HD
Thyssen Stahl AG, Duisburg, Germany
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Developed by Committee: A01
Pages: 252–270
DOI: 10.1520/STP24839S
ISBN-EB: 978-0-8031-5246-5
ISBN-13: 978-0-8031-1850-8