Quality of High-Carbon Chromium Bearing Steel Produced in the Electric Arc Furnace—Ladle Furnace—RH Vacuum Degassing Vessel—Vertical Continuous Caster

Uesugi, Toshikazu; Tsubota, Kazuichi

doi:10.1520/stp26241s

Cited by 12 publications

(1 citation statement)

References 5 publications

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“…In addition, these steels have good mechanical strength and high fatigue life. These characteristics result in mechanical properties are achieved through a rigid steelmaking process in the melt shop, where the liquid steel undergoes a series of refining reactions, including the removal of non-metallic inclusions (NMIs) through their transport, absorption and dissolution to the slag phase [1][2][3][4][5][6][7][8][9][10][11] . However, although all efforts made in the steel industry to strictly meet the cleanliness requirements (clean steels), it is still observed in the metallurgical processing of this steel, the residual of alumina (Al 2 O 3 ) inclusions, which are the product of deoxidation in Al-killed steels and spinel (MgO•Al 2 O 3 ) inclusions, formed by the presence of Mg in the liquid steel.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Spinel Based Inclusions During the Last Stage of The Steelmaking Process of SAE 52100

et al. 2020

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Al 2 O 3 (alumina) and MgO•Al 2 O 3 (spinel) inclusions cause valve obstruction (clogging) in continuous casting and can deteriorate the quality of the final product. In this context, industrial heats of the bearing steel SAE 52100 was examined. Samples were collected in the final steps of the steelmaking process, both after vacuum treatment and during continuous casting. A scanning electron microscope (SEM) equipped with a energy-dispersive spectrometer (EDS) and automated particle characterization analysis was used to characterize the inclusions present in the steel samples. Thermodynamic calculations were performed with the commercial software FactSage TM 7.2. Based on thermodynamic predictions, parameters such as solid fraction, liquid fraction, MgO saturation point of the slags, content of dissolved elements in steel (Al, Mg, Ca,...) and the construction of a phase stability diagram were determined. The results in this study showed a tendency for increase in MgO content in the inclusions with the decrease of %FeO and SiO 2 contents in the slag, an increase of binary basicity (%CaO/%SiO 2). It is verified that the MgO contents in the slag were close to the saturation, increasing the probability for the formation of inclusions rich in MgO and/or spinel. On the other hand, stability diagrams confirm the formation of spinel inclusions for each of the heats analyzed. During the final step of the steelmaking process, there is a tendency for re-oxidation, which is verified by an increase in the density of inclusions (or total oxygen TO values).

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Section: Introductionmentioning

confidence: 99%

Analysis of Spinel Based Inclusions During the Last Stage of The Steelmaking Process of SAE 52100

et al. 2020

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Chapter 2 | Basic Bearing Steel Metallurgy and Relationship of Steel Composition, Metallurgical Cleanliness, and Heat Treatment—Specifications and Standard Methods

Beswick¹

2022

Rolling Bearing Steel: Design, Technology, Testing and Measurements

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The microstructure of steels for rolling bearings is the single most important parameter in the metallurgy of steels for rolling bearings. The required spheroidize annealing operation for high carbon through hardening steels is reviewed. The microstructure produced in martensitic and bainitic through hardening processes are described as well as the carbide microstructure effects in secondary hardening treatment for steels for high temperature aerospace precision rolling bearings. Metallurgical cleanliness is an all-encompassing parameter in steels for rolling bearings and as such the various characteristics of inclusions present in rolling bearing steels are described. The effect of chemical elements in bearing steel compositions is treated with respect to their effects on rolling bearing properties. The international specifications and details of testing methods for steels for rolling bearings are explained and illustrated. The metallurgical specification and test parameters covered in this section are: microcleanliness, mesosize, defect control, macroinclusion testing using ultrasonic methods, microstructure control, steel composition testing, hardness testing, grinding burn, static capacity relationships, retained austenite and residual stress determination using x-ray diffraction, and radiation testing. The information in this section will enable the reader to identify the most important parameters for global sourcing and testing of steels for rolling bearings.

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Chapter 3 | Guide to Steel and Heat Treatment Selection—Rolling Bearing Material Design Relationships

Beswick¹

2022

Rolling Bearing Steel: Design, Technology, Testing and Measurements

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The steel technology parameters included in the rolling bearing steel metallurgical design are described. Steelmaking process costs related to metallurgical quality is explained. Air-melt steel is applied in less demanding applications and costly remelt high alloy and heat treatment formulations are used in high demanding bearings such as aerospace. Ball contact rolling bearings require somewhat different steel technologies as compared to line contact rolling bearings. Examples of metallurgical design relationships are explained with examples for ball and hub bearing units. The steel technology design correlations with dimensional stability, rolling contact fatigue, structural strength and tolerance to contamination, hydrogen and high temperature are explained. Steelmaking bloom, billet and bar reduction ratio, raceway forming flow conformance and large size ring hot forming dendritic breakdown requirements and relationships are clarified. The metallurgical parameters associated with through, case carburizing, and surface induction hardening are given for clean and contaminated rolling bearing operating environments. The use of secondary hardening steels for elevated temperature applications is introduced. The need for high metallurgical cleanliness is presented and its relationship with steelmaking processes. The three parameter cost—quality—manufacturing volume relationship is given. Metallurgical cleanliness measures such as oxygen content, micro, macro inclusion and titanium carbo-nitrides related to rolling contact fatigue strength are summarized. The factors to be considered in selection of appropriate heat treatments are described and in particular for elevated temperature rolling bearing used in aerospace applications. The importance of forming flow conformance in high alloy secondary hardening steels and the advantage of powder metallurgy processing of such steel technologies is introduced. High-temperature aircraft turbine engine bearing steel design parameters are given and in summary the key to cost-effective rolling bearing design is to know the requirements precisely and to apply the appropriate steel technologies.

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Quality of High-Carbon Chromium Bearing Steel Produced in the Electric Arc Furnace—Ladle Furnace—RH Vacuum Degassing Vessel—Vertical Continuous Caster

Cited by 12 publications

References 5 publications

Analysis of Spinel Based Inclusions During the Last Stage of The Steelmaking Process of SAE 52100

Analysis of Spinel Based Inclusions During the Last Stage of The Steelmaking Process of SAE 52100

Chapter 2 | Basic Bearing Steel Metallurgy and Relationship of Steel Composition, Metallurgical Cleanliness, and Heat Treatment—Specifications and Standard Methods

Chapter 3 | Guide to Steel and Heat Treatment Selection—Rolling Bearing Material Design Relationships

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