Recent Evaluation Procedures of Nonmetallic Inclusions in Bearing Steels (Statistics of Extreme Value Method and Development of Higher Frequency Ultrasonic Testing Method)

2009 ◽  
pp. 176-176-19 ◽  
Author(s):  
Y Kato ◽  
K Sato ◽  
K Hiraoka ◽  
Y Nuri
Keyword(s):  
Ultrasonic Testing ◽  
Nonmetallic Inclusions ◽  
Extreme Value ◽  
Testing Method ◽  
Evaluation Procedures ◽  
Bearing Steels ◽  
Recent Evaluation

Ultrasonic testing method

Ultrasonics ◽  
1971 ◽  
Vol 9 (2) ◽  
pp. 128
Author(s):  
L.C. Lynnworth
Keyword(s):  
Ultrasonic Testing ◽  
Testing Method

Corrosive Damage Close to Nonmetallic Inclusions in Bearing Steels

2018 ◽  
Vol 48 (3) ◽  
pp. 197-201
Author(s):  
S. I. Gubenko ◽  
A. B. Sychkov ◽  
E. V. Parusov ◽  
A. I. Denisenko ◽  
A. N. Zavalishchin
Keyword(s):  
Nonmetallic Inclusions ◽  
Bearing Steels

Nonmetallic inclusions in rails made of electro-steel alloyed with chromium

2020 ◽  
Vol 62 (12) ◽  
pp. 936-942 ◽  
Author(s):  
A. A. Umanskii ◽  
A. V. Golovatenko ◽  
A. S. Simachev
Keyword(s):  
Hot Deformation ◽  
Ultrasonic Testing ◽  
Nonmetallic Inclusions ◽  
Relative Concentration ◽  
Metallographic Analysis ◽  
High Ductility ◽  
High Concentration ◽  
Metallic Inclusions ◽  
Significant Concentration

Type, relative concentration and size of most characteristic non-metallic inclusions for the elements of rails (head, web) from electro-steel of E79KhF and E90KhАF grades were determined on the basis of metallographic (with a microscope “OLYMPUS GX-51”) and spectral (using spectrometer “ARL iSpark” method “Spark-DAT”) analyses. It was found that the highest relative concentration of manganese sulfides (MnS) is 30.8 – 43.4 ppm. At the same time, 60 – 100 % of inclusions of this type are of small sizes (less than 4 μm), and it does not allow them to be detected using standard metallographic analysis with 100-fold magnification. The revealed high relative concentration of sulfide inclusions directly correlates with the established positive sulfur liquation in considered rail elements, which is up to 40 %. Despite the high concentration of manganese sulfides, their influence on the quality of rails can be considered not dangerous, taking into account their high ductility during hot deformation and the established prevalence of inclusions of this type with small size (less than 4 μm). Among inclusions of a silicate type, SiO2 inclusions (3.4 – 14.9 ppm) have a significant concentration. All detected inclusions of this type have a size not exceeding 4 μm. It was found that the concentration of complex inclusions containing alumina (Al2O3 – CaO – MgO, Al2O3 – CaO – MgO – CaS, Al2O3 – CaO, Al2O3 – MgO) is insignificant: in total it does not exceed 3.1 ppm and 1.6 ppm for individual types. The concentration of corundum (Al2O3) is also insignificant and does not exceed 0.3 ppm. In this case, alumina inclusions of small size (less than 6 μm) prevail. Due to the low contamination (taking into account the relative concentration and size of inclusions) with non-plastic silicate and alumina non-metallic inclusions, their influence on the quality of the rails was not significant. It is confirmed by the absence of defects detected during ultrasonic testing.

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