scholarly journals Complex Precipitates of TiN-MCx in GCr15 Bearing Steel

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 641
Author(s):  
Qianren Tian ◽  
Guocheng Wang ◽  
Xinghu Yuan ◽  
Qi Wang ◽  
Seetharaman Sridhar
Keyword(s):  
Volume Fraction ◽  
Early Stage ◽  
Nucleation Site ◽  
Bearing Steel ◽  
Precipitation Behavior ◽  
Heterogeneous Nucleation Site ◽  
Bearing Steels ◽  
Advancing Front ◽  
Gcr15 Bearing Steel ◽  
Second Phases

Nitride and carbide are the second phases which play an important role in the performance of bearing steel, and their precipitation behavior is complicated. In this study, TiN-MCxprecipitations in GCr15 bearing steels were obtained by non-aqueous electrolysis, and their precipitation mechanisms were studied. TiN is the effective heterogeneous nucleation site for Fe7C3 and Fe3C; therefore, MCxcan precipitate on the surface of TiN easily. The chemistry component of MCx consists of M3C and M7C3 (M = Fe, Cr, Mn) and Cr3C2. TiN-MCx with high TiN volume fraction, TiN forms in early stage of solidification, and MCx precipitates on TiN surface after TiN engulfed by the solidification advancing front. TiN-MCx with low TiN volume fraction, TiN and MCx form in late stage of solidification, TiN can not grow sufficiently and is covered by numerous precipitated MCxparticles.

scholarly journals Complex Precipitates of TiN-MCx in GCr15 Bearing Steel

2019 ◽  
Author(s):  
Qianren Tian ◽  
Guocheng Wang ◽  
Xinghu Yuan ◽  
Qi Wang ◽  
Seetharaman Sridhar
Keyword(s):  
Volume Fraction ◽  
Early Stage ◽  
Nucleation Site ◽  
Bearing Steel ◽  
Precipitation Behavior ◽  
Heterogeneous Nucleation Site ◽  
Bearing Steels ◽  
Advancing Front ◽  
Gcr15 Bearing Steel ◽  
Second Phases

Nitride and carbide are the second phases which play an important role in the performance of bearing steel, and their precipitation behavior is complicated. In this study, TiN-MCx precipitations in GCr15 bearing steels were obtained by non-aqueous electrolysis, and their precipitation mechanisms were studied. TiN is the effective heterogeneous nucleation site for Fe7C3 and Fe3C, therefore, MCx can precipitate on the surface of TiN easily, its chemistry component consists of M3C and M7C3 (M = Fe, Cr, Mn) and Cr3C2. TiN-MCx with high TiN volume fraction, TiN forms in early stage of solidification, and MCx precipitates on TiN surface after TiN engulfed by the solidification advancing front. TiN-MCx with low TiN volume fraction, TiN and MCx form in late stage of solidification, TiN can not grow sufficiently and is covered by a large number of precipitated MCx particles.

The Study on the Precipitation and Mechanical Properties of Steel with Copper

2010 ◽  
Vol 654-656 ◽  
pp. 66-69 ◽  
Author(s):  
Chuang Li ◽  
Xue Min Wang ◽  
Xin Lai He ◽  
Cheng Jia Shang ◽  
Yu He
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Volume Fraction ◽  
Optical Microscope ◽  
Second Phase ◽  
Phase Precipitation ◽  
Precipitation Behavior ◽  
Quenching Temperature ◽  
Bearing Steels ◽  
Transition Electron

The properties and precipitation behavior of Cu-bearing steels have been investigated. The optical microscope and transition electron microscope were employed to study the influence of interrupted cooling and quenching temperature on the precipitation behavior. Also, the properties of samples with different quench processes were tested. The results show that when the steel is interruptedly cooled and quenched from 650-700°C, with the quenching temperature increasing the volume fraction of martensite becomes larger and the hardness becomes higher. When the microstructure is ferrite the second-phase precipitates occurs and they are proved copper-rich particles. However there are no obvious precipitates in martensite. The copper-rich second phase forms by the way of inter-phase precipitation.

Modeling and Simulation of Dynamic Recrystallization of GCr15 Steel Using Cellular Automaton Method

2013 ◽  
Vol 750 ◽  
pp. 156-159 ◽  
Author(s):  
Xiao Hu Deng ◽  
Zhou De Qu ◽  
Li Wen Zhang ◽  
Dong Ying Ju
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Cellular Automaton ◽  
Volume Fraction ◽  
Accurate Determination ◽  
Structural Evolution ◽  
Bearing Steel ◽  
Gcr15 Steel ◽  
Gcr15 Bearing Steel ◽  
Ca Model

A modified two-dimensional (2-D) cellular automaton (CA) model was constructed to simulate dynamic recrystallization (DRX) process of GCr15 steel. Particle stimulated nucleation (PSN) was incorporated into the CA model to determine the influence of dispersed particles on the nucleation of DRX. In addition, the model included the effects of particles on increasing the dislocation density and pinning the grain boundaries for accurate determination of micro-structural evolution during DRX. The model was applied to simulate the DRX process of GCr15 bearing steel. DRX grain size and volume fraction were simulated using the CA model. The simulated results indicated that the simulated stable grain size of particle-containing model is closer to measured value than particle-free model. It was observed that DRX kinetics depends on both thermo-mechanical parameters and initial grain sizes. The calculated results were compared with the experimental findings in GCr15 bearing steel, the predictions show very good agreement with the experimental results.

Orientational Analysis on Static Recrystallization at Tension Twins in AZ31 Magnesium Alloy

2011 ◽  
Vol 299-300 ◽  
pp. 778-784
Author(s):  
Xiao Li ◽  
Ping Yang ◽  
Li Meng
Keyword(s):  
Magnesium Alloy ◽  
Static Recrystallization ◽  
Volume Fraction ◽  
Early Stage ◽  
Nucleation Site ◽  
Az31 Magnesium Alloy ◽  
Basal Texture ◽  
Promotive Effect ◽  
Ebsd Technique ◽  
Evolution Of Microstructure

The deformation depends on twinning in Mg alloy, and twins will be the dominant recrystallization nucleation site. Tension twinning proceeds much more easily than compression twinning since its volume fraction is much higher than that of compression twins, which may have a promotive effect on the recrystallization to a certain degree. Based on the previous research on the static recrystallization at compression twins, the evolution of microstructure and texture in AZ31 magnesium alloy during its static recystallization at tension twins was further investigated; and the orientational characteristics of new grains formed at tension twins in the early stage of static recrystallization were analyzed by EBSD technique. The results showed that the strong basal texture was retained and weakened with no new texture component being detected during annealing. New grains were observed to nucleate preferentially at the intersections of tension twin variants or the intersection between tension twins and compression twins. Their orientations are relatively random and are strongly scattered from those of original tension twins or compression twins. A comparison of the recrystallization at tension twins and compression twins was further made.

Precipitation Behavior of Cd in Al-5wt.%Cu Based Alloy during Solidification

2012 ◽  
Vol 430-432 ◽  
pp. 964-967
Author(s):  
Min Li ◽  
Lan Rong Cai ◽  
Zhou De Qu
Keyword(s):  
Crystal Structure ◽  
Chemical Element ◽  
Nucleation Site ◽  
Hexagonal Structure ◽  
Precipitation Behavior ◽  
Heterogeneous Nucleation Site ◽  
Lattice Matching ◽  
Transmission Electron ◽  
Al2cu Phase ◽  
Scanning Electron

The precipitation behavior of Cd in an Al-5wt.%Cu based alloy during solidification were investigated, using scanning electron microscopy (SEM) and transmission electron microscope (TEM) observations. It has been found that a novel phase (Al4Cu) is observed except α-Al, θ-Al2Cu, T-Al12CuMn2 phases of Al-5wt.%Cu based alloy during solidification. This phase, with chemical element similar to Al2Cu, was present as closed hexagonal structure, which distributed dispersedly at the edge of grain boundary and adjacent to Al2Cu phase. Moreover, it has the same crystal structure with Cd and satisfies the lattice matching principle, which makes it suitable for the heterogeneous nucleation site for precipitation of Cd.

scholarly journals Quantitative Analysis of Inclusion Engineering on the Fatigue Property Improvement of Bearing Steel

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 476 ◽  
Author(s):  
Chao Gu ◽  
Min Wang ◽  
Yanping Bao ◽  
Fuming Wang ◽  
Junhe Lian
Keyword(s):  
Fatigue Life ◽  
Quantitative Analysis ◽  
Critical Size ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Fatigue Property ◽  
Bearing Steel ◽  
Fatigue Properties ◽  
Bearing Steels ◽  
Inclusion Distribution

The fatigue property is significantly affected by the inner inclusions in steel. Due to the inhomogeneity of inclusion distribution in the micro-scale, it is not straightforward to quantify the effect of inclusions on fatigue behavior. Various investigations have been performed to correlate the inclusion characteristics, such as inclusion fraction, size, and composition, with fatigue life. However, these studies are generally based on vast types of steels and even for a similar steel grade, the alloy concept and microstructure information can still be of non-negligible difference. For a quantitative analysis of the fatigue life improvement with respect to the inclusion engineering, a systematic and carefully designed study is still needed to explore the engineering dimensions of inclusions. Therefore, in this study, three types of bearing steels with inclusions of the same types, but different sizes and amounts, were produced with 50 kg hot state experiments. The following forging and heat treatment procedures were kept consistent to ensure that the only controlled variable is inclusion. The fatigue properties were compared and the inclusions that triggered the fatigue cracks were analyzed to deduce the critical sizes of inclusions in terms of fatigue failure. The results show that the critical sizes of different inclusion types vary in bearing steels. The critical size of the spinel is 8.5 μm and the critical size of the calcium aluminate is 13.5 μm under the fatigue stress of 1200 MPa. In addition, with the increase of the cleanliness of bearing steels, the improvement of fatigue properties will reach saturation. Under this condition, further increasing of the cleanliness of the bearing steel will not contribute to the improvement of fatigue property for the investigated alloy and process design.

TiN/ZrO2 multilayers synthesized on GCr15 bearing steel using plasma immersion ion implantation and deposition

2007 ◽  
Vol 201 (15) ◽  
pp. 6615-6618 ◽  
Author(s):  
Tao Sun ◽  
Langping Wang ◽  
Yonghao Yu ◽  
Yuhang Wang ◽  
Xiaofeng Wang ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Bearing Steel ◽  
Gcr15 Bearing Steel ◽  
Plasma Immersion Ion Implantation
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