Industrial experiment study on inclusion evolution in 95CrMo Steel

2019 ◽  
Vol 116 (5) ◽  
pp. 518 ◽  
Author(s):  
Linzhu Wang ◽  
Junqi Li ◽  
Shufeng Yang ◽  
Chaoyi Chen ◽  
Huixin Jin ◽  
...  
Keyword(s):  
Molten Steel ◽  
Single Phase ◽  
Oxide Inclusion ◽  
Complex Oxides ◽  
Inclusion Size ◽  
Refining Process ◽  
Cooling Process ◽  
Sharp Angle ◽  
Industrial Experiment ◽  
Industrial Experiments

In order to clarify the evolution mechanism of inclusions in 95CrMo, the industrial experiments were conducted. The composition, morphology and size of inclusions during refining and solidifying processes were analyzed by SEM-EDS detection and thermodynamic calculations. The inclusion evolution during refining process in molten 95CrMo steel can be concluded as: Al2O3 → Al2O3-MgO-CaO/CaS → Al2O3-MgO-SiO2-CaO-CaS, which is affected by slag-metal reaction and corrosion of refractory. The change of inclusion size during refining was analyzed based on their collision and floatation behavior. The composition of inclusions in billets indicate that there were mainly five types of inclusions, including spinel with sharp angle, spherical oxide inclusion composed of Al2O3, MgO, SiO2 and CaO, oxide-sulfide inclusion with single phase, inclusion with duplex phase, and MnS inclusion. The type of inclusions affects their size. The thermodynamic results indicate that most complex oxides formed in molten steel and no spinel generated during cooling process. CaS formed in the molten steel after tundish metallurgy and there were still some CaS precipitated in solid steel. MnS precipitated after steel solidification. The calculated results based on FACTSAGE 7.1 are in agreement with experimental results on the whole.

scholarly journals Inclusion Characteristics in 95CrMo Steels with Different Calcium and Sulfur Contents

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 619 ◽  
Author(s):  
Xiang Li ◽  
Xiao Long ◽  
Linzhu Wang ◽  
Shouhao Tong ◽  
Xiutao Wang ◽  
...  
Keyword(s):  
Outer Layer ◽  
Three Dimensional ◽  
Average Diameter ◽  
Inclusion Size ◽  
Number Density ◽  
Cooling Process ◽  
Oxide Inclusions ◽  
Industrial Experiments ◽  
Size Number

In order to study the effect of Ca and sulfur contents on the characteristics of inclusions, industrial experiments using 95CrMo steel were conducted. SEM-EDS detections and stereological analysis were used to probe the characteristics of inclusions, including their compositions, morphologies, size, number density, and distribution. The results indicate that there were mainly three types of inclusions in 95CrMo steel billets with 6–18 ppm Ca and 30–100 ppm S: inclusions with single-phased morphology mainly composed of oxides; isolated MnS/CaS-only inclusions; inclusions with multi-phased morphology. The three-dimensional inclusion size distribution suggests that there were more Type-1 inclusions with a small size in low S containing steels. The average diameter of all types of inclusions increased with increasing Ca or S content in 95CrMo steel, indicating that the formation of MnS and CaS coarsened their size. The density distribution of inclusions indicates that the more inclusions there are, the more easily they aggregate and collide. Moreover, it is presumably concluded that the formation of sulfide in the outer layer of oxide inclusions weaken the attraction between oxide inclusions. The equilibrated transformation and formation of inclusions during the cooling process of 95CrMo steel was discussed based on thermodynamic calculation. The equilibrated transformation trajectory of inclusions in 95CrMo steel during the cooling process was Ca2SiO4 + MgO → Ca3MgSi2O8 → Spinel + CaS, which was corresponding to the detected results. The precipitation regular of sulfide was obtained. The formation mechanism for three types of inclusions was discussed.

Investigation on the Novel Technology of the Fine Inclusion Removal due to the Dispersed In Situ Phase Induced by the Composite Ball Explosive Reaction

2011 ◽  
Vol 287-290 ◽  
pp. 1991-1996
Author(s):  
Peng Fei ◽  
Xiao Feng Wang ◽  
Yang Lin
Keyword(s):  
Molten Steel ◽  
Oxide Inclusion ◽  
Inclusion Size ◽  
Cast Slab ◽  
Inclusion Removal ◽  
Iron And Steel ◽  
Fine Inclusion ◽  
Novel Technology ◽  
Removal Technology

The production of high purity steel is a major task for the iron and steel enterprises in the 21stcentury. To improve the quality of steel products and produce the cleanness steel, the key technique is to control inclusions in the molten steel. In the present investigation, a novel fine inclusion removal technology due to the dispersed in-situ phase induced by the composite ball explosion reaction was put forward. A composite ball with this function has been designed and the industrial experimental investigation was also carried out. The results indicate that feeding composite ball in RH ladle is a novel technology and the inclusion in the molten steel can be removed effectively. Compared with conventional inclusion removal technology, the number of the oxide inclusion can be decreased to a lower level and the inclusion size becomes much finer. Using this novel technology, the total oxygen in the as-cast slab can approach to 6ppm. This novel technology can be achieved without special facility and be realized in most steelmaking plant.

Novel Concept of Cleansing the Liquid Steel by the Fine In-Situ Phase due to the Composite Ball Explosion Reaction in RH Ladle

2011 ◽  
Vol 239-242 ◽  
pp. 2895-2904
Author(s):  
Zhen Li ◽  
Xiao Feng Wang ◽  
Yang Lin ◽  
Peng Fei
Keyword(s):  
Molten Steel ◽  
Oxide Inclusion ◽  
Inclusion Size ◽  
Cast Slab ◽  
Inclusion Removal ◽  
Iron And Steel ◽  
Novel Technology ◽  
Removal Technology ◽  
Novel Concept

The production of high purity steel is a major task for the iron and steel enterprises in the 21stcentury. To improve the quality of steel products and produce the cleanness steel, the key technique is to control inclusions in the molten steel. In the present investigation, a novel fine inclusion removal technology due to the dispersed in-situ phase induced by the composite ball explosion reaction was put forward. A composite ball with this function has been designed and the industrial experimental investigation was also carried out. The results indicate that feeding composite ball in RH ladle is a novel technology and the inclusion in the molten steel can be removed effectively. Compared with conventional inclusion removal technology, the number of the oxide inclusion can be decreased to a lower level and the inclusion size becomes much finer. Using this novel technology, the total oxygen in the as-cast slab can approach to 6ppm. This novel technology can be achieved without special facility and be realized in most steelmaking plant.

Temperature Prediction Model for Molten Steel in RH Refining Process

2013 ◽  
Vol 712-715 ◽  
pp. 22-25 ◽  
Author(s):  
Tia Xia ◽  
Zhu He
Keyword(s):  
Mathematical Model ◽  
Prediction Model ◽  
Molten Steel ◽  
Initial Temperature ◽  
Refining Process ◽  
Temperature Prediction ◽  
Steel Temperature ◽  
Molten Steel Temperature

A mathematical model for the RH refining process was developed and validated by the measured molten steel temperature in situ. It is showed that the model predicted temperature matched the measured value well and the average errors within ±5°C were 86.9%. The model results also showed that for every increase of 100°C of the initial temperature of the chamber inwall , the average molten steel temperature increased by about 8°C. For every blowing extra 50m3 oxygen, the steel temperature increased by about 7°C.

scholarly journals New metal-oxide composite materials as efficient catalysts of the partial oxidation of methane

2019 ◽  
Vol 484 (3) ◽  
pp. 299-302
Author(s):  
A. G. Dedov ◽  
O. A. Slyakhtin ◽  
A. S. Loktev ◽  
G. N. Mazo ◽  
S. A. Malyshev ◽  
...  
Keyword(s):  
Partial Oxidation ◽  
Single Phase ◽  
Complex Oxides ◽  
Partial Oxidation Of Methane ◽  
Metallic Nickel ◽  
Oxidation Of Methane ◽  
Nickel Cobalt ◽  
Phase Complex ◽  
First Time ◽  
Properties Of Composites

Single-phase complex oxides Nd2-yCayCoxNi1-xO4 have been synthesized for the first time. Composites prepared by the reduction of these compounds with hydrogen and containing Nd2O3, CaO, and cobalt and nickels metals have been used for the first time as catalysts of the partial oxidation of methane. The maximal methane conversions (97%) and syngas yields (96%) at 900 °С have been detected in the presence of the composite obtained from Nd1,5Ca0,5NiO4. At T < 850 °C, the nickel–cobalt composite synthesized from Nd1,3Ca0,7Co0,4Ni0,6O4 turned out to be more selective in the formation of syngas. Decreasing the partial oxidation temperature from 900 °С to 750 °С leads to the oxidation of metallic nickel and cobalt to oxides and to partial resynthesis of complex oxides with perovskite and K2NiF4 structures. The observed differences in temperature dependence of the catalytic properties of composites with various Ni/Co ratios can be associated with the participation of complex oxides in catalysis of the partial oxidation of methane at low temperatures.

Effect of [Al]s, [Mg], [Ca] in Molten Steel on Inclusion Content for High Speed Wheel Steel during LF-VD Process

2014 ◽  
Vol 898 ◽  
pp. 60-63
Author(s):  
Yu Tang
Keyword(s):  
Fatigue Life ◽  
Molten Steel ◽  
High Speed ◽  
Refining Process ◽  
Fatigue Performance ◽  
Wheel Steel ◽  
Inclusion Content ◽  
High Basicity ◽  
Secondary Refining ◽  
Improve Fatigue

In order to improve fatigue life of wheel steel, LF-VD secondary-refining process is done with Al-deoxidation and slag of high basicity, high Al2O3 content and low oxidizing property. Inclusion content would be influenced by [Al]s, [Mg], [Ca] in molten steel. It is found that Al2O3 inclusions, which are the products of Al-deoxidation, would react with [Mg], [Ca] in molten steel to transform into CaO-MgO-Al2O3 complex inclusions, which is the key for the enhancement of fatigue performance for wheel steel.

Synthesis of the Gadolinium-Yttrium-Aluminum Garnet Activated with Cerium by Spraying High Aqueous Salt Solutions

2016 ◽  
Vol 721 ◽  
pp. 267-271 ◽  
Author(s):  
Aleksei Makeenko ◽  
Tatiana Larionova ◽  
Olga Klimova ◽  
Vitalii Galkin ◽  
Roman Starykh ◽  
...  
Keyword(s):  
Single Phase ◽  
Yttrium Aluminum Garnet ◽  
Complex Oxides ◽  
Drying Method ◽  
Garnet Structure ◽  
Salt Solutions ◽  
X Ray ◽  
Wide Range ◽  
Aqueous Salt Solutions ◽  
Yttrium Aluminum

The possibility of applying the spray drying method for the production of complex oxides powders with garnet structure is shown in paper. The processes occurring while heating of synthesized oxide-salt product, that lead to the formation of a material with a garnet structure were investigated by DTA, TGA, X-ray analysis. The possibility of producing single-phase structure of the garnet system (YxGd(3-x))3Al5O12 in wide range of compositions is demonstrated.

Effect of Slag Composition on [Mg], [Ca] Content in Molten Steel for High Speed Wheel Steel

2013 ◽  
Vol 746 ◽  
pp. 501-504
Author(s):  
Tang Yu
Keyword(s):  
Molten Steel ◽  
Slag Composition ◽  
High Speed ◽  
Refining Process ◽  
Wheel Steel ◽  
Complex Inclusion ◽  
High Basicity ◽  
Secondary Refining ◽  
Positive Factor ◽  
Improve Fatigue

In order to improve fatigue life of wheel steel, secondary-refining process is done with Al-deoxidation and slag of high basicity, high Al2O3 content and low oxidizing property. [M, [C content in molten steel would be influenced by slag composition. It is found that high basicity, high Al2O3 content and low oxidizing property is positive factor for proper [M, [C content in molten steel which is the key of inclusion transformation from Al2O3 to CaO-MgO-Al2O3 complex inclusion, contributing to the enhancement of fatigue performance for wheel steel.

Research on Technology of Smelting Low-Sulphur Steel

2012 ◽  
Vol 581-582 ◽  
pp. 899-903
Author(s):  
Long Kui Jiang
Keyword(s):  
Molten Steel ◽  
Refining Process ◽  
Sulphur Content ◽  
Converter Steelmaking ◽  
Hot Metal ◽  
Steel Smelting ◽  
Steel Refining

Based on feature of low-sulphur steel smelting in PanGang, in terms of optimizing desulfurization technology, reducing resulfurization in converter steelmaking, optimizing desulfurization in LF molten steel refining process and developing RH molten steel refining desulfurization technology. The sulphur content of hot metal can be controlled no more than 0.003%, and that of terminal molten steel can also be controlled no more than 0.005%, which makes the production of low-sulphur steel come true, and the technology route of such steel smelting be established.

Sign in / Sign up

Export Citation Format

Share Document