scholarly journals Effect of Acid Slag Treatment on the Inclusions in GCr15 Bearing Steel

2019 ◽  
Vol 38 (2019) ◽  
pp. 760-766
Author(s):  
Yang Liu ◽  
Jing Li ◽  
Jinpeng Ge ◽  
Dingli Zheng
Keyword(s):  
Spatial Distribution ◽  
Melting Point ◽  
Oxygen Content ◽  
Bearing Steel ◽  
Refining Slag ◽  
Slag Treatment ◽  
Gcr15 Bearing Steel ◽  
Inclusions In Steel

AbstractBy laboratory slag/steel reaction equilibrim experiments, the viriation of oxygen content, inclusion compositions and inclusion sizes were studied. The effect of acid slag treatment on the transition mechanisms of D-type inclusions and the precipitation of TiN inclusions in GCr15 bearing steel were explored. The obtained results showed that the dominant inclusions in steel were plastic and smaller Al2O3-SiO2-MnO. The melting point were lower than 1400°C treated by the acid refining slag of 35.1%CaO-15%Al2O3-43.9%SiO2-6%MgO and there was no TiN found. The evolution of MgO·Al2O3 inclusions is: MgO·Al2O3→ MgO·Al2O3·SiO2·MnO→ Al2O3·SiO2·MnO. Mg and Al from MgO·Al2O3 inclusions were displaced by [Si] and [Mn] in steel liquid , and formation of plastic Al2O3-SiO2-MnO inclusions finally, whose compositions distribution were uniform. Mg and Si, Mn were complementary in inclusions as to the spatial distribution.

Use of Recycled Calcium Slag for Clean Steel Refining

2009 ◽  
Vol 620-622 ◽  
pp. 635-638 ◽  
Author(s):  
Dong Ping Zhan ◽  
Hui Shu Zhang ◽  
Wei Gong ◽  
Zhou Hua Jiang ◽  
Ji Cheng He
Keyword(s):  
Pipeline Steel ◽  
Titanium Content ◽  
Bearing Steel ◽  
Refining Slag ◽  
Total Oxygen ◽  
Clean Steel ◽  
Gcr15 Bearing Steel ◽  
Steel Refining ◽  
Calcium Metal ◽  
Plant Trials

Calcium slag (CS) is a by-product generated during smelting to extract calcium metal from the ore by aluminothermic reduction method. The melting point, melting speed, viscosities, surface tensions and the refining effects of CS and normal premelted refining slag (NPRS) were measured in the laboratory. Then the plant trials were done in a 150 tons Ladle Furnace (LF) in a steelmaking plant during the refining of clean steel. The results show that the properties of CS are similar to those of NPRS, and CS is a good refining agent not only in laboratory experiment but also in industrial production. By using CS, the average final sulfur content in X70 pipeline steel reaches 25×10-6; the total oxygen content in GCr15 bearing steel is 5×10-6~8×10-6; the titanium content in GCr15 bearing steel is less than 20×10-6 and lower than the steels refined by using NPRS.

Application of Al-Mg Alloy in Bearing Steel

2009 ◽  
Vol 620-622 ◽  
pp. 387-390 ◽  
Author(s):  
Wei Gong ◽  
Zhou Hua Jiang ◽  
Dong Ping Zhan
Keyword(s):  
Oxygen Content ◽  
Spherical Shape ◽  
Inclusion Size ◽  
Bearing Steel ◽  
Mg Alloy ◽  
Total Oxygen ◽  
Total Oxygen Content ◽  
Alumina Inclusion ◽  
Inclusion Modification ◽  
Inclusions In Steel

There is less study about the effect of magnesium on characteristics of bearing. In the paper, the bearing steel was modified by three types of Al-Mg alloys. Firstly, the total oxygen content value was measured, and then the inclusion size, shape and chemical composition were analyzed by optical microscopy, SEM and EDX. The results show that, after treated by Al-Mg alloy, the total oxygen content descends remarkably and the alumina inclusion with big size and different shapes transform into spinel with small size and spherical shape. The optimal effect of inclusion modification is acquired after treated by NO. 3 Al-Mg alloy containing 16.55 wt% Mg, most of the inclusions in steel are spinel and magnesia, and the size of 96.23 wt% inclusions is less than 3μm.

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

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.

Effect of Refining Slag on the Inclusions of Hard Wire Steel during Melting Process

2011 ◽  
Vol 217-218 ◽  
pp. 1174-1179
Author(s):  
Yang Li ◽  
Zhou Hua Jiang ◽  
Shi You Yin ◽  
Ying Zhuang ◽  
Ming Li
Keyword(s):  
Ternary Phase Diagram ◽  
Melting Process ◽  
Melting Zone ◽  
Refining Slag ◽  
Total Oxygen ◽  
Deformation Ability ◽  
Inclusion Shape ◽  
Wire Steel ◽  
Al2o3 Inclusion ◽  
Inclusions In Steel

The effect of the refining slag composition on the total oxygen content and inclusions in steel was investigated in 100 t UHP Electric Furnace – LF – Billet CC process. The test steel was 77B hard wire steel and Si-Mn alloy was used as the deoxidizer. Three types slag were used in the industrial tests, which including CaO-CaF2, CaO-CaF2 adding CaC and CaO-Al2O3 refining slag. The results shown that the lowest total oxygen contents of rolled bar can be gained using the CaO-CaF2 refining slag adding CaC, which is 0.0036%, while the total oxygen contents of rolled bar using CaO-Al2O3 refining slag is higher a little than the heats using CaO-CaF2 refining slag. The CaO-SiO2 and CaO-Al2O3-SiO2 compound inclusions with the size of about 5 μm are the main inclusions in the heats refining by the CaO-CaF2 refining slag in the rolled bar, but the pure, indeformable Al2O3 inclusion can also be found with the size of about 10 μm. The CaO-Al2O3-SiO2 and Al2O3-SiO2-MnO compound inclusions are the main inclusions in the heats refining by the CaO-CaF2-CaC refining slag, but most of the inclusion shape is irregular with bigger size of about 10 μm. Similar with the heat using CaO-CaF2 refining slag, the pure Al2O3 inclusion with edge angle can be found in the rolled bar. The inclusions in the rolled bar treated by CaO-Al2O3 refining slag are CaO-Al2O3-SiO2 compound inclusions, most of which are nearly globular shape with the relative small size of about 5 μm. All of the inclusions in rolled bar lie on the low melting zone in the CaO-Al2O3-SiO2 ternary phase diagram in the heats using CaO-Al2O3 refining slag. The similar condition appeared on the most of the inclusions in the heats using CaO-CaF2 and CaO-CaF2 refining slag adding CaC, while part of which are lied on the high melting zone. Therefore, considering of the plastic deformation ability, the CaO-Al2O3 refining slag is the best slag for the melting process of hard wire steel.

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