A study of cast and thermomechanically hardened chromium-nickel nitrogen-bearing steel

2000 ◽  
Vol 42 (10) ◽  
pp. 342-347 ◽  
Author(s):  
V. G. Prokoshkina ◽  
L. M. Kaputkina ◽  
A. G. Svyazhin
Keyword(s):  
Bearing Steel ◽  
Hardened Chromium

Spray-Formed Bearing Steel with High Oxide Cleanliness and Small and Fine Dispersed Inclusions*

2014 ◽  
Vol 69 (6) ◽  
pp. 368-376 ◽  
Author(s):  
A. Schulz ◽  
W. Trojahn ◽  
C. Meyer ◽  
V. Uhlenwinkel
Keyword(s):  
Bearing Steel ◽  
Dispersed Inclusions

Effects of structural inhomogeneities on the steel balls resistance to loading

2020 ◽  
pp. 29-38
Author(s):  
O. B. Berdnik ◽  
I. N. Tsareva ◽  
L. A. Krivina ◽  
S. V. Kirikov ◽  
S. I. Gerasimov ◽  
...  
Keyword(s):  
Brittle Fracture ◽  
Bearing Steel ◽  
Metallographic Analysis ◽  
Structural Factors ◽  
Steel Shkh15 ◽  
Maximum Hardness ◽  
High Shock ◽  
Steel Balls ◽  
Plasticity Coefficient ◽  
Microstructure Of The Material

When conducting impact tests of protective glasses, nonunique cases of destruction of balls made of bearing steel ShKh15 were recorded. The causes of their destruction were determined. The state of the material was studied by fractographic and metallographic analysis, hardness and microhardness measurement. In the structure of the metal of all the balls, no critical defects were found such as flockens, shells and microcracks, but adverse factors were detected in the microstructure of the material, namely, the presence of fineneedle martensite with excessive carbides. It is established that the detected structural factors lead to liability to brittle fracture, an increase in the hardness of the material, a decrease in plasticity. To prevent brittle fracture of the balls and provide a reserve of plasticity of steel ShKh15 at high shock loads assessment calculations of ductility coefficient were made; and it was recommended to limit the maximum hardness of the material critical value HV=5.70 HPa (54 HRC), with the corresponding plasticity coefficient equal to 0.8.

scholarly journals Fatigue Crack Initiation and Propagation at High Temperature of New-Generation Bearing Steel

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 25
Author(s):  
Zhiwei Wu ◽  
Maosheng Yang ◽  
Kunyu Zhao
Keyword(s):  
Fracture Surface ◽  
Failure Mode ◽  
Electron Backscatter Diffraction ◽  
Fatigue Cracks ◽  
Fatigue Crack Initiation ◽  
Optical Microscope ◽  
Bearing Steel ◽  
Fatigue Properties ◽  
New Generation ◽  
Scanning Electron

The new generation of bearing steel has good comprehensive properties, which can satisfy most of the requirements of bearing steel in a complex environment. In the presented work, fatigue properties of 15Cr14Co12Mo5Ni2 bearing steel have been investigated by means of rotating bending fatigue tests on smooth bar specimens after carburization and heat treatment. Optical microscope, scanning electron microscopy, electron backscatter diffraction, and Image-Pro Plus software were used to analyze the fracture, microstructure, and carbides. The results suggest that the fatigue strength at room temperature and 500 °C is 1027 MPa and 585 MPa, respectively. Scanning electron micrographic observations on the fracture surface of the fatigue specimens at 500 °C show that fatigue cracks usually initiate from voids in the carburized case and oxide layer on the surface of steel. The failure mode in the carburized case is a quasi-cleavage fracture, and with the increase of crack propagation depth, the failure mode gradually changes to fatigue and creep-fatigue interaction. With the increase of the distance from the surface, the size of the martensite block decreases and the fracture surface shows great fluctuation.

scholarly journals The Effect of Flow Lines on the Mechanical Properties in Hot-Rolled Bearing Steel

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 456
Author(s):  
Dongsheng Qian ◽  
Chengfei Ma ◽  
Feng Wang
Keyword(s):  
Mechanical Characterization ◽  
Tensile Deformation ◽  
Flow Line ◽  
Plastic Property ◽  
Bearing Steel ◽  
Mechanical Anisotropy ◽  
Flow Lines ◽  
Significant Difference ◽  
Hot Rolled ◽  
Bearing Rings

Hot rolling is an essential process for the shape-forming of bearing steel. It plays a significant role in the formation and distribution of flow lines. In this work, the effect of flow lines is investigated by analyzing the microstructure and mechanical anisotropy of hot-rolled bearing steel. It was found that carbides rich with Cr and Mn elements are distributed unevenly along the flow-line direction of the hot-rolled bearing steel. Moreover, the mechanical characterization indicates that ultimate tensile strength and yield strength do not have any significant difference in two directions. Nevertheless, an ultrahigh section shrinkage of 57.51% is obtained in the 0° sample that has parallel flow lines, while 90° sample shows poor section shrinkage. The uneven distributed carbides will affect the direction and speed of crack propagation during tensile deformation. Therefore, the 0° and 90° samples exhibit great difference in plastic property. Meanwhile, after tensile deformation, a delaminated texture is observed in the flow lines, which may be caused by different degrees of deformation of grains due to the uneven distribution of carbides. The results of this work may provide guidance for controlling and optimizing flow lines in the manufacturing of bearing rings.

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