scholarly journals Predicting the microstructure evolution for the warm skew rolling of bearing steel balls under different process parameters

2020 ◽  
Vol 54 (1) ◽  
pp. 49-55
Author(s):  
Y. Huo ◽  
T. He ◽  
Y. Hu ◽  
W. Yang ◽  
M. Shen
Keyword(s):  
Process Parameters ◽  
Microstructure Evolution ◽  
Bearing Steel ◽  
Steel Balls ◽  
Skew Rolling

scholarly journals Study of the process of rolling steel balls in skew rolling mill – metallographic analysis

2021 ◽  
Vol 24 (1) ◽  
Author(s):  
Piotr Chyła
Keyword(s):  
Rolling Mill ◽  
Rolling Process ◽  
Dark Field ◽  
Bearing Steel ◽  
Metallographic Analysis ◽  
Modified Method ◽  
Microscopy Technique ◽  
Cooling Media ◽  
Steel Balls ◽  
Skew Rolling

This paper presents the results of metallographic research studies carried out for stock materials as well as the samples collected from the balls formed in the rolling process in a skew rolling mill. The stock material was bearing steel 100Cr6 and the steel from rail scrap. The rolling process was carried out in parallel for the two assumptions: the conventional method (hereinafter referred to as conventional rolling) and the modified method (hereinafter referred to as modified rolling). After the rolling process, three cooling media were used: air, water and oil. The pictures below, which depict microstructures, were taken using the bright-field and the dark-field microscopy technique, the samples were etched with a 4% solution of picral.

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 Influence of Deep Rolling and Induction Hardening on Microstructure Evolution of Crankshaft Sections made from 38MnSiVS5 and 42CrMo4

2021 ◽  
Vol 76 (3) ◽  
pp. 175-194
Author(s):  
A. Fischer ◽  
B. Scholtes ◽  
T. Niendorf
Keyword(s):  
Process Parameters ◽  
Microstructure Evolution ◽  
Surface Hardening ◽  
Qualitative Evaluation ◽  
Induction Hardening ◽  
Deep Rolling ◽  
Automotive Components ◽  
Hardening Treatment ◽  
Steel Grades ◽  
Definition Of

Abstract In order to improve properties of complex automotive components, such as crankshafts, in an application-oriented way, several surface hardening treatments can be applied. Concerning the material performance the definition of adequate process parameters influences the resulting surface properties and, thus, the effectiveness of surface hardening treatments. To analyze most relevant process-microstructure-property relationships, the present paper reports results obtained by two different well-established surface hardening procedures, i. e. deep rolling as a mechanical treatment and induction hardening as a thermal treatment. For each hardening process widely used crankshaft steel grades, i. e. a medium carbon 38MnSiVS5 microalloyed steel and a quenched and tempered 42CrMo4 were selected and thoroughly characterized upon processing, using equal parameter settings. The results reveal that deep rolling in contrast to induction hardening proves to be a less sensitive surface layer treatment with regard to small differences in the initial microstructure, the chemical composition and the applied process parameters. Differences in microstructure evolution with respect to the applied surface hardening treatment are studied and discussed for the highly stressed fillet region of automotive crankshaft sections for all conditions. In this context, high-resolution SEM-based techniques such as EBSD and ECCI are proven to be very effective for fast qualitative evaluation of induced microstructural changes.

Research on microstructure evolution of the three-roll skew rolling hollow axle

2021 ◽  
Author(s):  
Jitai Wang ◽  
Xuedao Shu ◽  
Song Zhang ◽  
Shuxin Li ◽  
Zbigniew Pater ◽  
...  
Keyword(s):  
Microstructure Evolution ◽  
Skew Rolling

Effect of process parameters on the microstructure evolution of laser surface quenched Ni-Al bronze

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040029
Author(s):  
Zhenbo Qin ◽  
Da-Hai Xia ◽  
Yida Deng ◽  
Wenbin Hu ◽  
Zhong Wu
Keyword(s):  
Grain Boundary ◽  
Process Parameters ◽  
Microstructure Evolution ◽  
Laser Scanning ◽  
Threshold Value ◽  
Laser Surface ◽  
High Rate ◽  
Fine Grained ◽  
Surface Quenching ◽  
Overlap Ratio

Laser surface quenching technology was used to modify the surface microstructure of as-cast Ni-Al bronze (NAB). The modified microstructure was studied by scanning electron microscopy (SEM), and the effect of laser process parameters on microstructure evolution was investigated. It was found that a fine-grained zone with fully [Formula: see text] phase microstructure formed on the surface of NAB. The depth of the fine-grained zone increased with the increase of laser power, and surface melting occurred when the power reached a threshold value. Laser scanning at a low rate caused the coarsening of grain boundary, while too high rate led to incomplete quenching. Spot overlap ratio determined the microstructure of the superimposed area, and unsuitable ratio would cause bulky [Formula: see text] precipitation at the grain boundary or incomplete transformation from [Formula: see text] phase to [Formula: see text] phase.

Mechanical Behavior and Microstructure Evolution of Bearing Steel 52100 During Warm Compression

JOM ◽  
2018 ◽  
Vol 70 (7) ◽  
pp. 1112-1117 ◽  
Author(s):  
Yuanming Huo ◽  
Tao He ◽  
Shoushuang Chen ◽  
Riming Wu
Keyword(s):  
Mechanical Behavior ◽  
Microstructure Evolution ◽  
Bearing Steel

A Study on Development of Forming Roller for Miniature Metal Balls Manufacturing Process

2007 ◽  
Vol 539-543 ◽  
pp. 2518-2523
Author(s):  
H.S. Joe ◽  
J.S. Park ◽  
Y.H. Kim
Keyword(s):  
Process Parameters ◽  
Manufacturing Process ◽  
Manufacturing System ◽  
Fem Simulation ◽  
Basic Design ◽  
Knife Edge ◽  
Processing Parameter ◽  
Processing Property ◽  
Rigid Plastic ◽  
Steel Balls

According as the demand of miniature metal balls of various diameter increases, processing property and a variety of coverage are important. In this study, especially an optimal groove design of cutting roller was investigated for determining size and shape of metal ball in the manufacturing system. The effects of radius of the groove and radius of the knife-edge of cutting roller and the speed of roller as process parameters were calculated and analyzed. We applied data of rigid-plastic FEM Simulation with DEFORM3D and ANSYS in basic design of equipment to solve these issues, and checked processing parameter about metal balls manufacturing process that use cutting process of metal wire stock in this research. This paper deals with the new improved process of producing miniature STS316L steel balls continuously. Our first goal is to develop a much more efficient equipment and a much more economical production process

scholarly journals Influencing Factors of Void closure in Skew-Rolled Steel Balls Based on the Floating-Pressure Method

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1391
Author(s):  
Chang Shu ◽  
Jitai Wang ◽  
Xuedao Shu ◽  
Duanyang Tian
Keyword(s):  
Numerical Analysis ◽  
Influencing Factors ◽  
Influencing Factor ◽  
Uniform Design ◽  
Metal Flow ◽  
Rolled Steel ◽  
Void Closure ◽  
Pressure Method ◽  
Steel Balls ◽  
Skew Rolling

Due to the instable conditions caused by the wear of rollers, macro voids inevitably occur in skew rolling steel balls. Macro voids in rolled balls greatly weakens the mechanical properties, resulting in the scrapping of about 23% of all skew rolling balls. This paper adopts the floating-pressure method (FPM) to eliminate macro voids in rolled steel balls, and mainly focuses on the investigation of the influencing factor void closure in skew-rolled balls. The research contents are listed as follows: Firstly, the mechanical model of FPM eliminating void in rolled steel balls is established, and the theoretical relationship between influencing factors of void closure is obtained. Then, the metal flow behaviors, the stress distribution and the effect of process parameters on void closure are revealed by numerical analysis. Subsequently, based on the uniform design method, the prediction equation of the required temperature and air pressure for compacting various inferior rolled balls with different diameter by FPM is deduced. Finally, the FPM experiment is carried out to verify the results of numerical analysis. The research results provide theoretical guidance for eliminating macro voids in skew-rolled steel balls.

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