scholarly journals Effect of alloying and microstructure on formability of advanced high-strength steels processed via quenching and partitioning

2021 ◽  
pp. 142217
Author(s):  
P. Xia ◽  
F. Vercruysse ◽  
C. Celada-Casero ◽  
P. Verleysen ◽  
R.H. Petrov ◽  
...  
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Quenching And Partitioning ◽  
Advanced High Strength Steels ◽  
Effect Of Alloying

scholarly journals The Effect of Alloying on Mechanical Properties of Advanced High Strength Steels

2014 ◽  
Vol 59 (3) ◽  
pp. 1189-1192 ◽  
Author(s):  
L. Kučerová ◽  
H. Jirková ◽  
B. Mašek
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Cooling Rate ◽  
High Strength Steels ◽  
High Strength ◽  
Microstructure Development ◽  
Quenching And Partitioning ◽  
Advanced High Strength Steels ◽  
Quenching And Partitioning Process ◽  
Effect Of Alloying

Abstract Quenching and partitioning process with incorporated incremental deformation was optimized for six high strength steels with various contents of carbon (0.4-0.6%), manganese (0.6-1.2), silicon (2-2.6%) and chromium (0.8-1.3%). The optimization was gradually done for each steel with respect to the final microstructures and properties. The effect of cooling rate, quenching and partitioning temperature on microstructure development was further investigated. Interesting combinations of mechanical properties were obtained, with tensile strength in the region of 1600-2400 MPa and ductility of 6-20%.

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%.

Microstructural Evolution of Medium Carbon Steels during the Quenching and Partitioning Process

2010 ◽  
Vol 654-656 ◽  
pp. 86-89 ◽  
Author(s):  
Hong Yan Li ◽  
Xue Jun Jin
Keyword(s):  
Lath Martensite ◽  
High Strength Steels ◽  
High Strength ◽  
Lower Bainite ◽  
Carbon Steels ◽  
Medium Carbon ◽  
Quenching And Partitioning ◽  
Multiphase Microstructure ◽  
Advanced High Strength Steels ◽  
Medium Carbon Steels

The “Quenching and Partitioning” (Q&P) process is a novel heat treatment designed for processing new generation advanced high strength steels (AHSS) with substantial ductility. In this study, evolution of complex microstructure for medium carbon steels during the Q&P process has been discussed in detail. Such steels have shown a complex multiphase microstructure consisted of fresh lath-martensite, fresh plate-martensite, transition carbide and/or cementite, isothermal martensite/lower bainite, and second twin-martensite after the one-step Q&P process (with the identical quenching and partitioning temperature). The morphology for the microstructure at room temperature after the two-step Q&P process (with different quenching and partitioning temperatures) demonstrated a little different. The formation of different microstructure for these two processes and their correlation with the mechanical properties are discussed.

Quenching and Partitioning of Ni-Added High Strength Steels

2007 ◽  
Vol 539-543 ◽  
pp. 4476-4481 ◽  
Author(s):  
F.C. Rizzo ◽  
A.R. Martins ◽  
John G. Speer ◽  
David K. Matlock ◽  
A. Clarke ◽  
...  
Keyword(s):  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
Processing Parameters ◽  
Carbide Formation ◽  
X Ray Diffraction ◽  
Quenching And Partitioning ◽  
Steel Microstructure ◽  
Advanced High Strength Steels ◽  
Treatment Procedures

High strength steels containing significant fractions of retained austenite have been developed in recent years, and are the subject of growing commercial interest when associated with the TRIP phenomenon during deformation. A new process concept “quenching and partitioning” (Q&P) has been proposed by CSM/USA, and the results show the potential to create a new kind of steel microstructure with controlled amounts of retained austenite, enriched by carbon partitioning. Four steels containing C, Si, Mn, Ni, Cr and Mo, were designed with variation in the Ni and C content, aiming to decrease Bs temperature and to suppress carbide formation during the partitioning treatment. Several heat-treatment procedures were performed in specimens previously machined for tensile testing, while x-ray diffraction was used to determine the fraction of retained austenite. The tensile test results showed that except for the high C high Ni alloy, most of the processing conditions resulted in strengths superior to those of advanced high strength steels (AHSS), although it is importantly recognized that higher alloy additions were used in this study, in comparison with conventional AHSS grades.. A variety of strength and ductility combinations were observed, confirming the potential of the Q&P process and illustrating the strong influence of the final microstructure on the mechanical properties. Experimental results for samples partitioned at 400 °C indicate that higher ultimate tensile strength is associated with higher fraction of retained austenite for multiple heat treatments of each alloy investigated. The amount of retained austenite obtained was generally lower than that predicted by the model. Further studies are in progress to understand the influence of alloying and processing parameters (time/temperature) on the partitioning of carbon and precipitation of transition carbides.

scholarly journals Temperature Dependence of the Static and Dynamic Behaviour in a Quenching and Partitioning Processed Low-Si Steel

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 509 ◽  
Author(s):  
Florian Vercruysse ◽  
Carola Celada-Casero ◽  
Bernd M. Linke ◽  
Patricia Verleysen ◽  
Roumen H. Petrov
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Trip Effect ◽  
Quenching And Partitioning ◽  
Advanced High Strength Steels ◽  
Wide Range

Because of their excellent combination of strength and ductility, quenching and partitioning (Q & P) steels have a great chance of being added to the third generation of advanced high strength steels. The large ductility of Q & P steels arises from the presence of 10% to 15% of retained austenite which postpones necking due to the transformation induced plasticity (TRIP) effect. Moreover, Q & P steels show promising forming properties with favourable Lankford coefficients, while their planar anisotropy is low due to a weak texture. The stability of the metastable austenite is the key to obtain tailored properties for these steels. To become part of the newest generation of advanced high strength steels, Q & P steels have to preserve their mechanical properties at dynamic strain rates and over a wide range of temperatures. Therefore, in the present study, a low-Si Q & P steel was tested at temperatures from −40 °C to 80 °C and strain rates from 0.001 s−1 to 500 s−1. Results show that the mechanical properties are well-preserved at the lowest temperatures. Indeed, at −40 °C and room temperature, no significant loss of the deformation capacity is observed even at dynamic strain rates. This is attributed to the presence of a large fraction of austenite that is so (thermally) stable that it does not transform in the absence of deformation. In addition, the high stability of the austenite decreases the elongation at high test temperatures (80 °C). The additional adiabatic heating in the dynamic tests causes the largest reduction of the uniform strain for the samples tested at 80 °C. Quantification of the retained austenite fraction in the samples after testing confirmed that, at the highest temperature and strain rate, the TRIP effect is suppressed.

scholarly journals The Effect of Mn and Si on the Properties of Advanced High Strength Steels Processed by Quenching and Partitioning

2010 ◽  
Vol 654-656 ◽  
pp. 94-97 ◽  
Author(s):  
Bohuslav Mašek ◽  
Hana Jirková ◽  
Daniela Hauserova ◽  
Ludmila Kučerová ◽  
Danuše Klauberová
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
Volume Fraction ◽  
High Strength Steels ◽  
High Strength ◽  
Microstructural Development ◽  
X Ray Diffraction ◽  
Quenching And Partitioning ◽  
Advanced High Strength Steels ◽  
High Ultimate Strength

The concepts new types of materials are, for economic reasons, focused mainly on low alloyed steels with a good combination of strength and ductility. Suitable heat and thermo-mechanical treatments play an important role for the utilization of these materials. Different alloying strategies are used to influence phase transformations. The quenching and partitioning process (Q-P Process) is one of the heat treatment methods which can result in a high ultimate strength as well as a good ductility. However, these good properties can be obtained only if a sufficient amount of retained austenite is stabilized. The influence of different contents of manganese, silicon and chromium on microstructural development and mechanical properties were experimentally tested. Alloying elements were used to stabilize the retained austenite in the final microstructure and also to strengthen the solid solution. Ultimate strengths of over 2000MPa with ductility over 10% were reached after the optimization of the Q-P Process. The microstructures were analyzed using several microscopic methods; mechanical properties were determined by a tensile test and the volume fraction of the retained austenite was established by X-ray diffraction phase analysis.

scholarly journals Advanced High-Strength Steels by Quenching and Partitioning

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1419
Author(s):  
Ilchat Sabirov ◽  
María J. Santofimia ◽  
Roumen H. Petrov
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Chemical Compositions ◽  
Quenching And Partitioning ◽  
Advanced High Strength Steels ◽  
Heating And Cooling

Quenched and partitioned (Q&P) steels are recently developed materials with carefully selected chemical compositions and multiphase microstructures resulting from precisely controlled heating and cooling processes [...]

The Multiphase Micro- and Nanostructures of 0.2 and 0.4 C Direct-Quenched and Partitioned Steels

2021 ◽  
Vol 1016 ◽  
pp. 1097-1102
Author(s):  
Sakari Pallaspuro ◽  
Ilkka Miettunen ◽  
S. Assa Aravindh ◽  
Sumit Ghosh ◽  
Wei Cao ◽  
...  
Keyword(s):  
Density Functional ◽  
High Strength Steels ◽  
High Strength ◽  
Density Functional Theory Calculations ◽  
Processing Route ◽  
Slow Cooling ◽  
Quenching And Partitioning ◽  
Main Research ◽  
Direct Quenching ◽  
Advanced High Strength Steels

Quenching and partitioning produces advanced high-strength steels that utilise transformation-induced plasticity for improved strength and deformability. Microstructures of these steels consist mainly of tempered martensite and carbon-enriched retained austenite. A novel processing route of direct-quenching and partitioning (DQP) facilitates carbon partitioning from supersaturated martensite to untransformed austenite directly from the quench-stop temperature in a decelerated cooling that simulates slow cooling of a coiled strip. A major advantage of DQP steels is that they keep both the costs and emissions down by inexpensive alloying and energy-efficient processing. In this study, we investigate the microstructures of 0.2C and 0.4C laboratory hot-rolled DQP steels with comparison to a direct-quenched variant with high-resolution transmission electron microscopy as the main research technique. We show that the structures of DQP steels have frequent nanotwinned regions and can contain three different crystal structures with characteristic length scales ranging from few nm to ~200 nm. This is in remarkable contrast to the traditional lath-martensitic microstructure of the as-quenched material. Density functional theory calculations provide further insight into these findings with the calculated results of energetics, and show that carbon helps in stabilising the newly found omega phase. These results give further insight to the aspects that must be considered when assessing their effect on essential mechanical properties like strain hardening and toughness.

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