Modified quenching temperature selection method for partial austenitization quenching and partitioning steel

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%.

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Effect of Quenching and Partitioning Processing on Microstructure and Mechanical Properties of a Low Alloyed Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.941.52 ◽

2018 ◽

Vol 941 ◽

pp. 52-57

Author(s):

Bernd Pfleger ◽

Marina Gruber ◽

Gerald Ressel ◽

Peter Gruber ◽

Matthew Galler ◽

...

Keyword(s):

Mechanical Properties ◽

High Strength ◽

Phase Evolution ◽

Tensile Tests ◽

Austenite Phase ◽

Phase Fraction ◽

Quenching Temperature ◽

Quenching And Partitioning ◽

Low Alloyed Steel ◽

A Minor

The concept of quenching and partitioning (Q&P) is a tool to generate steels with high strength and high ductility resulting from a relatively high amount of martensite and austenite. As the parameters of the Q&P treatment influence the strength and ductility properties, the goal of this work was to analyze the effects of varying quenching and partitioning temperatures on the phase evolution, on the retained austenite phase fraction and on the mechanical properties. The phase evolution during heat treatment was analyzed by dilatometer and the microstructure after processing was characterized by light microscopy in combination with color etching according to Klemm. The austenite phase fraction and its carbon content were determined by X-Ray diffraction and the mechanical properties were evaluated by tensile tests. It is shown that the quenching temperature has a minor impact on the phase fraction of austenite as well as its stabilization by carbon and thus, also the mechanical properties. Furthermore, austenite transformation during the partitioning treatment is illustrated.

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Modified Methodology for the Quench Temperature Selection in Quenching and Partitioning (Q&P) Processing of Steels

Metallurgical and Materials Transactions A ◽

10.1007/s11661-016-3579-3 ◽

2016 ◽

Vol 47 (8) ◽

pp. 3797-3802 ◽

Cited By ~ 9

Author(s):

Eun Jung Seo ◽

Lawrence Cho ◽

Bruno C. De Cooman

Keyword(s):

Temperature Selection ◽

Quenching And Partitioning ◽

Quench Temperature

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Effects of Quenching and Partitioning Process on Mechanical Properties of a Hot-Stamping Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.788.340 ◽

2014 ◽

Vol 788 ◽

pp. 340-345 ◽

Cited By ~ 5

Author(s):

Ming Cheng ◽

Hong Wu Song ◽

Xin Li ◽

Shi Hong Zhang ◽

Ming Cheng ◽

...

Keyword(s):

Mechanical Properties ◽

Treatment Process ◽

Volume Fraction ◽

Hot Stamping ◽

Quenching Temperature ◽

Quenching And Partitioning ◽

22Mnb5 Steel ◽

Partitioning Time ◽

Hot Stamping Steel ◽

Quenching And Partitioning Process

As a novel heat treatment process, Q&P (quenching and partitioning) process can be applied to enhance the ductility of steels. In this paper, the effects of different parameters of Q&P process (such as quenching temperature, partitioning temperature and partitioning time) on mechanical properties and microstructure of 22MnB5 steel was investigated. Analysis demonstrated that austenite can be stabilized via Q&P process and the volume fraction of retained austenite increases with the partitioning temperature and the partitioning time. The mechanical properties of the steel can be controlled to acquire the steel with excellent strength-ductility balance by Q&P process.

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A Study of the Optimum Quenching Temperature of Steels with Various Hot Rolling Microstructures after Cold Rolling, Quenching and Partitioning Treatment

Metals ◽

10.3390/met8080579 ◽

2018 ◽

Vol 8 (8) ◽

pp. 579 ◽

Cited By ~ 3

Author(s):

Bin Chen ◽

Juhua Liang ◽

Tao Kang ◽

Ronghua Cao ◽

Cheng Li ◽

...

Keyword(s):

Electron Backscatter Diffraction ◽

High Strength ◽

Quenching Temperature ◽

Austenite Grain Size ◽

Quenching And Partitioning ◽

Transmission Electron ◽

Cold Rolled ◽

Lower Temperature ◽

Means Of Transmission ◽

Hot Rolled

Quenching and partitioning (Q&P) processes were applied to a cold-rolled high strength steel (0.19C-1.26Si-2.82Mn-0.92Ni, wt %). The effects of the prior hot-rolled microstructure on the optimum quenching temperature of the studied steels were systematically investigated. The microstructure was analyzed by means of transmission electron microscope (TEM), electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). Compared with the ferrite pearlite mixture matrix, the lower martensite start (Ms) temperature and smaller prior austenite grain size in the cold-rolled martensite matrix are the main reasons for the optimum quenching temperature shifting to a lower temperature in the Q&P steels. We found that an empirical formula that only considers the influence of the alloy composition in the calculation of the Ms temperature will cause a certain interference to the pre-determined optimum quenching temperature of the Q&P steel.

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A New Hot Stamping Process with Quenching and Partitioning Treatment

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1095.673 ◽

2015 ◽

Vol 1095 ◽

pp. 673-676 ◽

Cited By ~ 1

Author(s):

Pei Xing Liu ◽

Xiang Yun Yu ◽

Kai Wang ◽

Bin Zhu ◽

Jian Li ◽

...

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Retained Austenite ◽

Hot Stamping ◽

Quenching Temperature ◽

Quenching And Partitioning ◽

Servo Press ◽

Stamping Process ◽

Partitioning Time

A new hot stamping process with quenching and partitioning treatment is proposed in the paper. Compared to direct hot stamping process, the microstructures with some retained austenite not only including martensite are formed according to the constrained carbon equilibrium (CCE) model. During the new hot stamping process, tools with high temperature are used to control the quenching temperature (QT) between Ms and Mf, and the partitioning treatment of the part is also implemented in the tools by prolonging holding times. In this paper, different holding times (partitioning times) controlled by servo press, are used to research the influence of partitioning time on mechanical properties.

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Microstructure Analysis and Mechanical Properties of Low Alloy High Strength Quenched and Partitioned Steel

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.258.574 ◽

2016 ◽

Vol 258 ◽

pp. 574-578 ◽

Cited By ~ 2

Author(s):

Farnoosh Forouzan ◽

Suresh Gunasekaran ◽

Ali Hedayati ◽

Esa Vuorinen ◽

Frank Mücklich

Keyword(s):

Mechanical Properties ◽

Retained Austenite ◽

Lath Martensite ◽

High Strength ◽

Microstructure Analysis ◽

Quenching Temperature ◽

Precipitate Formation ◽

Quenching And Partitioning ◽

Fine Grained ◽

Impact Tests

Gleeble study of the quenching and partitioning (Q&P) process has been performed on Domex 960 steel (Fe, 0.08 %C, 1.79 %Mn, 0.23 %Si, 0.184 %Ti, and 0.038 %Al). The effect of different Q&P conditions on microstructure and mechanical properties were investigated. The aim of the process is to produce a fine grained microstructure for better ductility and controlled amounts of different micro-constituents to increase the strength and toughness simultaneously. Three different quenching temperatures, three partitioning temperatures and three partitioning times have been selected to process the 27 specimens by Gleeble® 1500. The specimens were characterized by means of OM, SEM, XRD, hardness and impact tests. It was found that, fine lath martensite with retained austenite is achievable without high amount of Si or Al in the composition although lack of these elements may cause the formation of carbides and decrease the available amount of carbon for partitioning into the austenite. The hardness increases as the quenching temperature is decreased, however, at highest partitioning temperature (640◦C) the hardness increases sharply due to extensive precipitate formation.

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