scholarly journals Generation Mechanism of MgO and Al2O3 Inclusions in 51CrV4 Spring Steel Based on the Ion–Molecule Coexistence Theory

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 830 ◽  
Author(s):  
Jialiu Lei ◽  
Hangyu Zhu ◽  
Dongnan Zhao ◽  
Zhengliang Xue
Keyword(s):  
Spring Steel ◽  
Generation Mechanism ◽  
Mass Action ◽  
Fatigue Properties ◽  
Nozzle Clogging ◽  
Steel Billet ◽  
Al Content ◽  
Coexistence Theory ◽  
Mass Action Concentration ◽  
Mg Content

The presence of MgO·Al2O3 inclusions in 51CrV4 spring steel is detrimental to the alloy’s castability and fatigue properties. To effectively suppress these inclusions during production, accretions were collected from the immersion nozzle, and the MgO·Al2O3 inclusions in the steel billet were investigated. The generation mechanism of the inclusions was evaluated based on the ion–molecule coexistence theory, and the mass action–concentration model of CaO–SiO2–Al2O3–MgO–FeO–MnO slag was developed. Industrial experiments showed that nozzle clogging was primarily caused by MgAl2O4 spinel inclusions, and the MgO·Al2O3 spinel inclusions in the steel billet were investigated by non-aqueous electrolysis. The model calculation results indicate that the Mg content increased with an increasing basicity, CaO/Al2O3 ratio, and Al content during the ladle furnace (LF) process. In contrast, the Mg content decreased with increasing CO pressure under Ruhstahl-Hausen vacuum degassing process (RH) conditions.

A Thermodynamic Model for Evaluation of Mass Action Concentrations of La2O3-Al2O3-CaF2-CaO-MgO Slags for Electroslag Remelting Based on the Ion and Molecule Coexistence Theory

2013 ◽  
Vol 32 (6) ◽  
pp. 541-550 ◽  
Author(s):  
Chengchuan Wu ◽  
Guoguang Cheng ◽  
Jun Tian
Keyword(s):  
Phase Diagrams ◽  
Thermodynamic Model ◽  
Mass Fraction ◽  
Electroslag Remelting ◽  
Mass Action ◽  
Coexistence Theory ◽  
Maximum Value ◽  
Mass Action Concentration ◽  
Increasing Temperature ◽  
Good Agreement

AbstractAccording to the ion and molecule coexistence theory (IMCT) for molten slags and corresponding phase diagrams, a thermodynamic model for the evaluation of mass action concentrations (designated by Ni for structure unit i) for La2O3-Al2O3, La2O3-Al2O3-CaF2, La2O3-Al2O3-CaF2-CaO, La2O3-Al2O3-CaF2-MgO and La2O3-Al2O3-CaF2-CaO-MgO slag systems for electroslag remelting (ESR) has been formulated. The influencing factors for the mass action concentration of La2O3, such as mass fraction of Al2O3, CaF2, CaO and MgO and temperature, were investigated. The results show that when the mole fraction of La2O3 is at 0.495, the mass action concentration of La2O3 · Al2O3 achieves its maximum value 0.946 in the La2O3-Al2O3 binary slag. In a composition area of La2O3: 10wt% ∼ 45wt%, Al2O3: 0wt% ∼ 50wt% and CaF2: 20wt% ∼ 70wt% of the La2O3-Al2O3-CaF2 ternary slag at 1873 K, the results show that the calculated values of NLa2O3 are in good agreement with the reported measured values of aLa2O3. The iso-curves of NLa2O3 is also drawn from the calculated results, which reveals that the mass action concentration of La2O3 decreases with the increasing of the Al2O3 and CaF2 content, and Al2O3 is stronger than CaF2 in decreasing the mass action concentration of La2O3. However, in La2O3-Al2O3-CaF2-CaO, La2O3-Al2O3-CaF2-MgO and La2O3-Al2O3-CaF2-CaO-MgO slag systems, the mass action concentration of La2O3 increases with the increasing of the MgO and CaO content, and CaO is stronger than MgO in increasing the mass action concentration of La2O3. In addition, the mass action concentration of La2O3 increases with the increasing temperature at the composition of 30wt%La2O3, 10wt%Al2O3, 40wt%CaF2, 10wt%MgO and 10wt%CaO.

A Thermodynamic Model for Evaluation of Mass Action Concentrations of Ce2O3-contained Slag Systems Based on the Ion and Molecule Coexistence Theory

2013 ◽  
Vol 32 (3) ◽  
pp. 207-214 ◽  
Author(s):  
Chengchuan Wu ◽  
Guoguang Cheng ◽  
Hu Long ◽  
Xiaohong Yang
Keyword(s):  
Phase Diagrams ◽  
Thermodynamic Model ◽  
Mass Fraction ◽  
Aluminum Content ◽  
Mass Action ◽  
Coexistence Theory ◽  
Cerium Content ◽  
Maximum Value ◽  
Mass Action Concentration ◽  
Good Agreement

AbstractAccording to the ion and molecule coexistence theory (IMCT) for molten slags and corresponding phase diagrams, a thermodynamic model for the evaluation of mass action concentrations (designated by Ni for structure unit i) for Ce2O3-Al2O3, CaO-Al2O3-Ce2O3 and CaO-Al2O3-SiO2-Ce2O3 slag systems has been formulated. The results show that when the mole fraction of Ce2O3 is at 0.49 in the binary slag, the mass action concentration of Ce2O3·Al2O3 achieves its maximum value 0.90. In a composition area of CaO/Al2O3 (mass fraction ratio) from 0.7 to 1.5 and Ce2O3 content (mass fraction) from 0 to 45% of the ternary slag at 1773 K, the results show that trends of calculated NAl2O3 are in good agreement with reported measured trends of aAl2O3. The iso-curves of NCe2O3 and NCaO are also drawn from the calculated results. A thermodynamic model of the equilibrium between 55.83%CaO-23%Al2O3-11.17%SiO2-10%Ce2O3 quaternary slag and molten steel containing aluminum has been further discussed. Results indicate that certain content of Ce would be dissolved in steel, which increases with the increasing of temperature and aluminum content, and when the aluminum content is 0.02%, the corresponding cerium content is in the range of 1.87 to 13.30 ppm at 1873 K. In summary, using Ce2O3 to replace Al2O3 can effectively reduce NAl2O3, certain content of Ce can dissolved in steel.

Calculation Model of Mass Action Concentration for CaO-B2O3-SiO2 Slag System

2013 ◽  
Vol 634-638 ◽  
pp. 3114-3117 ◽  
Author(s):  
Hong Ming Wang ◽  
Xiang Zhu ◽  
Gui Rong Li
Keyword(s):  
Slag System ◽  
Calculation Model ◽  
Slag Basicity ◽  
Mass Action ◽  
Coexistence Theory ◽  
B2o3 Content ◽  
Maximum Value ◽  
Slag Structure ◽  
Mass Action Concentration

According to the coexistence theory of melted slag structure, a calculation model of mass action concentrations for CaO-B2O3-SiO2 slag system has been established, by which the mass action concentrations of all structure units in CaO-B2O3-SiO2 systems are calculated. The results indicate that the activities of CaO and 2CaO•SiO2 can be decreased effectively by B2O3. Furthermore, when the slag basicity is higher than 2.0, the activity of 2CaO•SiO2 increases firstly and then decreases with the increasing of B2O3 content. The activity of CaO increases with the increasing of slag basicity. When the basicity is less than 2.2, the activity of 2CaO•SiO2 increases with the increase of slag basicity. Moreover, when the basicity is 2.2, the activity of 2CaO•SiO2 reaches the maximum value. In another word, the activity of 2CaO•SiO2 decreases with the increase of slag basicity on the condition that the slag basicity exceeds 2.2. B2O3 exists in the slag in the form of CaO•B2O3, 2CaO•B2O3 and 3CaO•B2O3.

INLAND DURASPRING

Alloy Digest ◽  
1998 ◽  
Vol 47 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Tensile Properties ◽  
High Stress ◽  
High Strength ◽  
Spring Steel ◽  
Fatigue Properties ◽  
Light Truck ◽  
Suspension Systems ◽  
Spring Steels

Abstract Inland DuraSpring is a high-strength microalloyed spring steel for use in high stress coil springs for automobile and light truck suspension systems. This bar product offers significant improvements in tensile strength, fatigue properties, and fracture toughness compared to conventional spring steels. This datasheet provides information on composition, hardness, and tensile properties as well asfracture toughness and fatigue. Filing Code: SA-496. Producer or source: Ispat Inland Inc.

Inclusions, lining materials and nozzle clogging during middle carbon steel billet continuous casting process

2008 ◽  
Vol 105 (2) ◽  
pp. 72-79 ◽  
Author(s):  
Shihong Liu ◽  
Xinhua Wang ◽  
Xiangjun Zuo ◽  
Yufeng Wang ◽  
Lifeng Zhang ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Continuous Casting ◽  
Casting Process ◽  
Continuous Casting Process ◽  
Nozzle Clogging ◽  
Steel Billet ◽  
Billet Continuous Casting

Microstructure Characteristic of AZ31/7005 Joints by GTAW with Filler Wire of Mg-Al Alloy

2014 ◽  
Vol 1004-1005 ◽  
pp. 168-171
Author(s):  
Hong Yan Du ◽  
Yaj Jang Li ◽  
Juan Wang
Keyword(s):  
Solid Solution ◽  
Intermetallic Compounds ◽  
Fusion Zone ◽  
Weld Zone ◽  
Dissimilar Materials ◽  
Eutectic Structure ◽  
Al Alloy ◽  
Test Results ◽  
Al Content ◽  
Mg Content

Mg/Al dissimilar materials were welded successfully by GTAW with SAlMg-1 and SAlMg-2 welding wire of Mg-Al system. The nice weld shape and free defects of joints are obtained. The test results indicated that continuous lamellar intermetallic compounds is not found The structure of Mg side in the fusion zone is composed of α-Mg solid solution+ β-Al12Mg17eutectic structure and precipitates β-A112lMg17on the grain boundary. The structure in the weld zone is mainly α-Mg solid solution + β-A112lMg17solid solutions. Mg and Al content are stable in the fusion zone of Mg side. However, in the weld zone of Mg side the Mg content is decreased gradually, and the Al content is increased that reaches a stable level in the weld zone of Al side. As a result, when Mg content in the wire can hold a proper level, the intermetallic compounds will be controlled effectively, and the performance of AZ31/7005 welding joint can be improved.

scholarly journals Tensile and fatigue properties of laser-welded ultra-high-strength stainless spring steel lap joints

2019 ◽  
Vol 36 ◽  
pp. 131-137 ◽  
Author(s):  
Mikko Hietala ◽  
Antti Järvenpää ◽  
Markku Keskitalo ◽  
Matias Jaskari ◽  
Kari Mäntyjärvi
Keyword(s):  
High Strength ◽  
Lap Joints ◽  
Spring Steel ◽  
Fatigue Properties

Microstructural influence on fatigue properties of a high-strength spring steel

1998 ◽  
Vol 241 (1-2) ◽  
pp. 30-37 ◽  
Author(s):  
C.S Lee ◽  
K.A Lee ◽  
D.M Li ◽  
S.J Yoo ◽  
W.J Nam
Keyword(s):  
High Strength ◽  
Spring Steel ◽  
Fatigue Properties
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