scholarly journals Quenching and Partitioning of Multiphase Aluminum-Added Steels

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 373 ◽  
Author(s):  
Tuomo Nyyssönen ◽  
Olli Oja ◽  
Petri Jussila ◽  
Ari Saastamoinen ◽  
Mahesh Somani ◽  
...  
Keyword(s):  
Tensile Testing ◽  
Retained Austenite ◽  
Intercritical Annealing ◽  
Annealing Condition ◽  
Quenching And Partitioning ◽  
Multiphase Structure ◽  
Austenite Fraction ◽  
Quench Temperature

The quenching and partitioning response following intercritical annealing was investigated for three lean TRIP-type high-Al steel compositions. Depending on the intercritical austenite fraction following annealing, the steels assumed either a ferrite/martensite/retained austenite microstructure or a multiphase structure with ferritic, bainitic and martensitic constituents along with retained austenite. The amount of retained austenite was found to correlate with the initial quench temperature and, depending on the intercritical annealing condition prior to initial quenching, with the uniform and ultimate elongations measured in tensile testing.

Hydrogen Embrittlement Resistance of High Strength 9260 Bar Steel Heat Treated by Quenching and Partitioning

2021 ◽  
Author(s):  
E. Hoyt ◽  
E. De Moor ◽  
K.O. Findley
Keyword(s):  
Hydrogen Embrittlement ◽  
Carbon Content ◽  
Hydrogen Concentration ◽  
Retained Austenite ◽  
Volume Fraction ◽  
High Strength ◽  
Quenching And Partitioning ◽  
Quench Temperature ◽  
Embrittlement Resistance ◽  
Hydrogen Embrittlement Resistance

Abstract The influence of microstructure on hydrogen embrittlement of high strength steels for fastener applications is explored in this study. Space limiting applications in areas such as the automotive or agricultural industries provide a need for higher strength fasteners. Albeit, hydrogen embrittlement susceptibility typically increases with strength. Using a 9260 steel alloy, the influence of retained austenite volume fraction in a martensitic matrix was evaluated with microstructures generated via quenching and partitioning. X-ray diffraction and scanning electron microscopy were used to assess the influence of retained austenite in the matrix with different quenching parameters. The quench temperatures varied from 160 °C up to 220 °C, and a constant partitioning temperature of 290 °C was employed for all quench and partitioned conditions. The target hardness for all testing conditions was 52-54 HRC. Slow strain rate tensile testing was conducted with cathodic hydrogen pre-charging that introduced a hydrogen concentration of 1.0-1.5 ppm to evaluate hydrogen embrittlement susceptibility of these various microstructures. The retained austenite volume fraction and carbon content varied with the initial quench temperature. Additionally, the lowest initial quench temperature employed, which had the highest austenite carbon content, had the greatest hydrogen embrittlement resistance for a hydrogen concentration level of 1.0-1.5 ppm.

Microstructure and Mechanical Properties of a Low-Carbon Steel Treated by One-Step Quenching and Partitioning Process

2014 ◽  
Vol 1082 ◽  
pp. 202-207 ◽  
Author(s):  
Shu Yan ◽  
Xiang Hua Liu
Keyword(s):  
Mechanical Properties ◽  
Carbon Steel ◽  
Microstructural Evolution ◽  
Retained Austenite ◽  
Uniform Elongation ◽  
Low Carbon Steel ◽  
Total Elongation ◽  
Low Carbon ◽  
Quenching And Partitioning ◽  
Partitioning Time

A low carbon steel was treated by quenching and partitioning (Q&P) process, and a detailed characterization of the microstructural evolution and testing of mechanical properties were carried out. The resulted mechanical properties indicate that with the partitioning time increasing, the tensile strength decreases rapidly first and then remains stable, and the total elongation increases first then decreases. The investigated steel subjected to Q&P process exhibits excellent products of strength and elongation (17.8-20.6 GPa•%). The microstructural evolution of martensite matrix during the partitioning step was observed, and the morphology and content of retained austenite were characterized. The working hardening behavior of the samples was analyzed, and the retained austenite with higher carbon content contributes to the uniform elongation more effectively.

scholarly journals Carbon Redistribution and Microstructural Evolution Study during Two-Stage Quenching and Partitioning Process of High-Strength Steels by Modeling

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2302 ◽  
Author(s):  
Yilin Wang ◽  
Huicheng Geng ◽  
Bin Zhu ◽  
Zijian Wang ◽  
Yisheng Zhang
Keyword(s):  
Retained Austenite ◽  
Volume Fraction ◽  
High Strength Steels ◽  
High Strength ◽  
Simulation Method ◽  
Low Carbon ◽  
Two Stage ◽  
Quenching And Partitioning ◽  
Carbon Redistribution ◽  
Carbon Martensite

The application of the quenching and partitioning (Q-P) process on advanced high-strength steels improves part ductility significantly with little decrease in strength. Moreover, the mechanical properties of high-strength steels can be further enhanced by the stepping-quenching-partitioning (S-Q-P) process. In this study, a two-stage quenching and partitioning (two-stage Q-P) process originating from the S-Q-P process of an advanced high-strength steel 30CrMnSi2Nb was analyzed by the simulation method, which consisted of two quenching processes and two partitioning processes. The carbon redistribution, interface migration, and phase transition during the two-stage Q-P process were investigated with different temperatures and partitioning times. The final microstructure of the material formed after the two-stage Q-P process was studied, as well as the volume fraction of the retained austenite. The simulation results indicate that a special microstructure can be obtained by appropriate parameters of the two-stage Q-P process. A mixed microstructure, characterized by alternating distribution of low carbon martensite laths, small-sized low-carbon martensite plates, retained austenite and high-carbon martensite plates, can be obtained. In addition, a peak value of the volume fraction of the stable retained austenite after the final quenching is obtained with proper partitioning time.

scholarly journals Effect of Quenching and Partitioning Temperatures in the Q-P Process on the Properties of AHSS with Various Amounts of Manganese and Silicon

2012 ◽  
Vol 706-709 ◽  
pp. 2734-2739 ◽  
Author(s):  
Hana Jirková ◽  
Ludmila Kučerová ◽  
Bohuslav Mašek
Keyword(s):  
Tensile Strength ◽  
Retained Austenite ◽  
Isothermal Holding ◽  
Bainitic Ferrite ◽  
High Strength Steels ◽  
High Strength ◽  
Experimental Program ◽  
Quenching Temperature ◽  
Quenching And Partitioning ◽  
Advanced High Strength Steels

The use of the combined influence of retained austenite and bainitic ferrite to improve strength and ductility has been known for many years from the treatment of multiphase steels. Recently, the very fine films of retained austenite along the martensitic laths have also become the centre of attention. This treatment is called the Q-P process (quenching and partitioning). In this experimental program the quenching temperature and the isothermal holding temperature for diffusion carbon distribution for three advanced high strength steels with carbon content of 0.43 % was examined. The alloying strategies have a different content of manganese and silicon, which leads to various martensite start and finish temperatures. The model treatment was carried out using a thermomechanical simulator. Tested regimes resulted in a tensile strength of over 2000MPa with a ductility of above 14 %. The increase of the partitioning temperature influenced the intensity of martensite tempering and caused the decrease of tensile strength by 400MPa down to 1600MPa and at the same time more than 10 % growth of ductility occurred, increasing it to more than 20%.

Application of Quenching-Partitioning-Tempering Process in Hot Rolled Plate Fabrication

2010 ◽  
Vol 654-656 ◽  
pp. 82-85 ◽  
Author(s):  
Shu Zhou ◽  
Ying Wang ◽  
Nai Lu Chen ◽  
Yong Hua Rong ◽  
Jian Feng Gu
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
Significant Fraction ◽  
Rolled Plate ◽  
Quenching And Partitioning ◽  
Good Ductility ◽  
Hot Rolled ◽  
Rolled Plates

The quenching-partitioning-tempering (Q-P-T) process, based on the quenching and partitioning (Q&P) treatment, has been proposed for producing high strength steels containing significant fraction of film-like retained austenite and controlled amount of fine martensite laths. In this study, a set of Q-P-T processes for C-Mn-Si-Ni-Nb hot rolled plates are designed and realized. The steels with Q-P-T processes present a combination of high strength and relatively good ductility. The origin of such mechanical properties is revealed by microstructure characterization.

Influence of Mn and Ni on Austenite Stabilization during a High Temperature Q&P Treatment

2021 ◽  
Vol 1016 ◽  
pp. 379-384
Author(s):  
Eider Del Molino ◽  
Teresa Gutierrez ◽  
Mónica Serna-Ruiz ◽  
Maribel Arribas ◽  
Artem Arlazarov
Keyword(s):  
Phase Transformation ◽  
Electron Microscope ◽  
High Temperature ◽  
Retained Austenite ◽  
Nickel Content ◽  
X Ray Diffraction ◽  
Quenching And Partitioning ◽  
X Ray ◽  
Scanning Electron ◽  
P Cycle

The aim of this work was to study the influence of quenching and partitioning temperatures combined with various levels of Mn and Ni contents on the austenite stabilization along the quenching and partitioning (Q&P) cycle. Three steels with 2 wt.%, 4 wt.% and 6 wt.% manganese and one steel with 2 wt.% nickel content were investigated. Phase transformation temperatures and critical cooling rates were obtained experimentally using dilatometer for each alloy. Q&P cycles with different quenching and partitioning temperatures were also done in dilatometer, thus, allowing monitoring of the expansion/contraction during the whole Q&P cycle. Microstructure characterization was performed by means of a Scanning Electron Microscope and X-Ray Diffraction to measure retained austenite content. It was found that, strongly depending on the Q&P conditions, austenite stabilization or decomposition occurs during partitioning and final cooling. In case of high partitioning temperature cycles, austenite reverse transformation was observed. Certain cycles resulted in a very effective austenite stabilization and interesting microstructure.

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