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Properties of through hardening bearing steels produced by BOF blowing metallurgy and by electric arc furnace with ladle metallurgy
Author(s) -
Baum Rudolf,
Böhnke Kurt,
Boeckers Tilman,
Klemp Harald
Publication year - 1987
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.198700243
Subject(s) - metallurgy , ladle , ingot , machinability , materials science , carbide , hardening (computing) , casting , machining , composite material , alloy , layer (electronics)
Melting in EAF and BOF‐TBM and different methods of aluminium deoxidation in the subsequent ladle treatment result in a similar degree of cleanness. With respect to micro‐inclusions the air melted ingot and continuous cast steels achieve nearly the same level as remelted steels. Considering macro‐inclusions there still remains a decisive difference: remelted steel is sure to be free from macro‐inclusions, whereas some occasionally occur in air melted steel. The random test and metallographic evaluation systems do not allow uniform classification of the various steel groups. None of the applied methods can determine definite inclusion contents. The number and sizes of the evaluated types of inclusions only can define the statistical probability of their occurrence in a larger lot of heats. Up to now they cannot be related to the fatigue behaviour of the steels. Therefore, further investigation is necessary to reveal the effect of critical sizes and chemistry of the various inclusions on the fatigue behaviour. First tests reveal that the machinability seems to be governed by the carbide grain sizes more than by the sulphur contents in the investigated range of 0.003‐0.015%. The comparison of test results in terms of cleanness and segregation shows that continuous casting should allow the same application as ingot casting.