scholarly journals Investigation into the dephosphorization of ferromanganese alloys for the production of advanced high-strength steel

2021 ◽  
Vol 121 (9) ◽  
pp. 1-9
Author(s):  
M.P. Maphutha ◽  
J.D. Steenkamp ◽  
P.C. Pistorius
Keyword(s):  
Partition Coefficient ◽  
Steel Industry ◽  
High Strength Steel ◽  
Induction Furnace ◽  
High Strength Steels ◽  
High Strength ◽  
Laboratory Scale ◽  
Motor Vehicles ◽  
Advanced High Strength Steel ◽  
Advanced High Strength Steels

Advanced high-strength steels (AHSS) are sophisticated materials being developed by the steel industry to mitigate challenges related to the performance of motor vehicles. To meet the requirements of AHSS, the ferromanganese alloys (FeMn) utilized in the production of the steel are required to contain acceptable levels of unwanted impurities, i.e. P, S, N, H, and C. The focus of the current study was to investigate dephosphorization of ferromanganese to produce a low-P alloy that could be effectively utilized in the production of AHSS. The study involved conducting laboratory-scale testwork to study the efficiency of CaO-based slag systems to dephosphorize FeMn alloys. The addition of Na2O, CaF2, and BaO to MnO-CaO-SiO2 slag was considered. The test work was carried out in a 25 kW induction furnace at temperatures of 1350°C, 1400°C, and 1450°C. The P partition coefficient (Lp) remained small at <1, which is an indication that dephosphorization had not been achieved. The baseline slag, comprising 40%CaO-40%SiO2-20%MnO, reported higher Lpvalues. Addition of Na2O and CaF2 did not show any further benefit. Substituting half of the CaO by BaO, resulted in similar Lpvalues to those of the baseline slag under conditions of 1350°C and 1450°C at 30 minutes. In summary, based on the Lpvalues obtained, the conditions investigated with the CaO-based slags appeared to have been unfavourable for dephosphorization of FeMn alloys, as most of this impurity element remained in the alloy.

An Innovative Shearing Process for AHSS Edge Stretchability Improvements

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Hua-Chu Shih ◽  
Ming F. Shi
Keyword(s):  
High Strength Steel ◽  
High Strength Steels ◽  
High Strength ◽  
Straight Edge ◽  
Forming Process ◽  
Expansion Test ◽  
Advanced High Strength Steels ◽  
Sheared Edge ◽  
Shear Edge

A beveled shear hole piercing process has recently been developed for advanced high strength steel (AHSS). The preliminary results have shown the new process is able to improve the quality of the sheared edge and the edge stretchability of AHSS. The goal of the current study is to optimize the beveled shearing process and identify the optimal shearing conditions for AHSS. Four different advanced high strength steels, including DP600, DP780, TRIP780, and DP980 with various thicknesses together with a conventional high strength steel, HSLA50, are selected in this study. The hole expansion test is used to evaluate the effect of shear edge conditions on the edge stretchability. The results show that an optimal selection of the die clearance and the shearing angle results in a less damaged edge, which significantly delays edge fracture in the forming process and increases the edge stretchability for AHSS. To further validate the advantages of the beveled shearing process in improving the shear edge quality of AHSS, a straight edge shearing device with the capability of adjusting the shearing variables (rake angles and die clearance) with respect to different sheet thicknesses was also developed and built. The edge stretchability of the straight edge sheared specimen was then evaluated using the sheared edge tension test. A similar trend to the beveled shear hole piercing process of AHSS is observed, and a significant improvement in the edge stretchability is also obtained with optimal shearing conditions.

Study of a Novel Ultra-High Strength Steel with Adequate Ductility and Toughness by Quenching-Partitioning-Tempering Process

2010 ◽  
Vol 654-656 ◽  
pp. 37-40 ◽  
Author(s):  
Ying Wang ◽  
Shu Zhou ◽  
Zheng Hong Guo ◽  
Yong Hua Rong
Keyword(s):  
Electron Microscopy ◽  
High Strength Steel ◽  
High Strength Steels ◽  
High Strength ◽  
X Ray Diffraction ◽  
Advanced High Strength Steels ◽  
New Family ◽  
Transmission Electron ◽  
Ultra High Strength Steel ◽  
Base Steel

According to the design principle of microstructures for high strength steel and a new quenching-partitioning-tempering (Q-P-T) process recently proposed by Hsu, a microalloying Fe-Mn-Si base steel by the Q-P-T process has been designed. The results indicate that the Q-P-T steel exhibits ultra-high tensile strength combining with good ductility and toughness, and it is a new family of advanced high-strength steels. The microstructures of samples by different Q-P-T processes were characterized by means of optical microscopy, scanning electron microscopy, X-ray diffraction and transmission electron microscopy, and the relation between microstructures and mechanical properties was analyzed

Effect of Cr and Thermomechanical Processing on the Microstructure and Mechanical Properties of Advanced High-Strength Steel

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Abdel-Wahab El-Morsy ◽  
Ahmed I. Z. Farahat
Keyword(s):  
Thermomechanical Processing ◽  
High Strength Steels ◽  
High Strength ◽  
Air Cooling ◽  
Third Generation ◽  
Advanced High Strength Steel ◽  
Thermomechanical Process ◽  
Advanced High Strength Steels ◽  
Treatment Processes ◽  
Cooling Air

In this work, two advanced high-strength steels (AHSS) have been developed by designing alloy systems with suitable alloying elements, Mn, Si, Al, and Cr, and postforming heat treatment processes. Thermomechanical process of ∼90% forging reductions has been applied on the designed alloys at a temperature of 1100 °C, followed by austenitizing above AC3. Four cooling rates, air-cooling, air-cooling with tempering, oil quenching with tempering, and water quenching with tempering, have been applied on the forged samples. The results revealed that the estimated tensile properties of the ferrite/bainite microstructures of alloy A, without Cr, is situated between the bands of the first and the current third generation AHSS, whereas the estimated properties corresponding to the ferrite/fine bainite with 8% retained austenite of alloy B, with Cr, is overlapped with the properties exhibited by the current third generation of AHSSs. The thermomechanical process conducted on the alloy containing Cr has developed steel with tensile strength up to 1790 MPa.

Continuous Casting of Advanced Steels of Near-Peritectic Composition

2010 ◽  
Vol 654-656 ◽  
pp. 17-22 ◽  
Author(s):  
Rian J. Dippenaar
Keyword(s):  
Continuous Casting ◽  
Phase Transformations ◽  
Automotive Industry ◽  
Peritectic Reaction ◽  
Composition Range ◽  
High Strength Steels ◽  
High Strength ◽  
Current Understanding ◽  
Motor Vehicles ◽  
Advanced High Strength Steels

The automotive industry is increasingly utilizing advanced high-strength steels, primarily to reduce the mass of motor vehicles. However, many of these steels fall within the peritectic composition range, which are notoriously difficult to cast by continuous casting techniques. Against this background, a brief review is given of our current understanding of the peritectic reaction as such and the subsequent peritectic phase transformations.

Numerical modeling of stress-strain relationships for advanced high strength steels

2021 ◽  
Vol 182 ◽  
pp. 106687
Author(s):  
Yu Xia ◽  
Chu Ding ◽  
Zhanjie Li ◽  
Benjamin W. Schafer ◽  
Hannah B. Blum
Keyword(s):  
Numerical Modeling ◽  
High Strength Steels ◽  
High Strength ◽  
Stress Strain ◽  
Advanced High Strength Steels
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