The "quenching and partitioning" process: background and recent progress

Speer, John G.; Rizzo, F.; Matlock, David K.; Edmonds, David

doi:10.1590/s1516-14392005000400010

Cited by 294 publications

(127 citation statements)

References 11 publications

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“…This cycle of heat treatment is an alternative route for obtaining multi-phase steel, where the volumetric fraction of retained austenite is controlled by the phenomenon of carbon partition from the martensite until the austenite is stabilized 1 . The concept of quenching and partition involves partial transformation of the austenite to martensite, through a quenching at temperatures between Ms (martensite start temperature) and Mf (martensite final temperature), followed by a thermal partitioning treatment, which allows the carbon to diffuse from the supersaturated martensite to the non-transformed austenite.…”

Section: Introductionmentioning

confidence: 99%

“…The stabilization of austenite using the carbon from martensite only will be possible with the existence of non-transformed austenite after quenching and if the carbide precipitation is suppressed or retarded by the presence of silicon or aluminum alloy additions 1 . If these conditions are fulfilled, it is possible to obtain austenite enriched with carbon, which will be stable at room temperature.…”

Section: Introductionmentioning

confidence: 99%

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Quenching and partitioning heat treatment in ductile cast irons

Silva¹,

Goldenstein

Guesser

et al. 2014

Mat. Res.

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A commercial ductile iron alloy was submitted to a quenching and partitioning heat treatment. Samples were austenitized at 900 °C for two hours, quenched at 160 °C and kept at this temperature for 2 minutes and finally were re-heated at temperatures between 300 and 450 °C during time intervals between 2 and 180 minutes. The microstructural evaluation was performed with SEM and X-ray diffraction and the mechanical properties were measured using tensile strength and Charpy tests. In general, the quenching and partitioning treatment is viable to achieving expressive fractions of retained austenite in ductile cast irons. Generally, higher partitioning temperatures produce a higher fraction of retained austenite after shorter times. This behavior can be explained by the increase on diffusion rate of carbon at higher temperatures. For all tested conditions it was possible to see a well-defined process window and the combination of mechanical properties is very similar to the austempered ductile irons.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quenching and partitioning heat treatment in ductile cast irons

Silva¹,

Goldenstein

Guesser

et al. 2014

Mat. Res.

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“…This produces a mixture of martensite and retained austenite. 2,3 The workpiece is then heated to, and held at, the partitioning temperature (PT). 4 With regard to the austenite stabilization, carbon must not precipitate in the form of carbides at the PT.…”

Section: Qandp Processingmentioning

confidence: 99%

Production of shaped semi-products from AHS steels by internal pressure

Vorel¹,

Jirková²,

Mašek³

et al. 2015

Mater. Tehnol.

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The constant evolution of industry brings demands for components of ever-higher quality, complex shapes and excellent mechanical properties, with reduced operating costs and with improved reliability in service. Such demands can be met by processing high-strength, low-alloyed steels using novel heat-treatment methods. One of such methods is the quenching and partitioning (Q&P) process, which can lead to high strengths of about 2000 MPa at elongation levels of more than 10 %. The Q&P process can be combined with unconventional procedures for making complex-shaped parts to manufacture components with excellent mechanical properties and an intricate shape. This paper describes the sequence of internal high-pressure forming, hot stamping and the Q&P process used for making a functional product with good mechanical properties and a complex shape. The purpose of the experimental programme was to employ a production chain for processing hollow, thin-walled stock. Using a step-by-step optimization, commercially usable products were obtained. The microstructure of the products consisted primarily of martensite and a small fraction of bainite. Such a microstructure guarantees a high ultimate strength. The strength level throughout the part was not less than 1950 MPa, combined with an excellent elongation of approximately 15 %. Keywords: Q&P process, hot stamping, internal high pressure forming Stalen razvoj industrije zahteva komponente vedno bolj{ih kvalitet, kompleksnih oblik, odli~nih mehanskih lastnosti pri ni`jih proizvodnih stro{kih in z ve~jo zanesljivostjo obratovanja. Take zahteve se lahko dose`ejo z izdelavo visokotrdnostnih malolegiranih jekel z uporabo novih metod toplotne obdelave. Ena od takih metod je postopek kaljenja in delitve (Q&P), ki omogo~a velike trdnosti okrog 2000 MPa pri ve~kot 10-odstotnem raztezku. Postopek Q&P se lahko kombinira z nekonvencionalnimi metodami izdelave delov s kompleksno obliko in za izdelavo komponent z odli~nimi mehanskimi lastnostmi in komplicirano obliko. Predstavljeni~lanek obravnava zaporedne operacije notranjega visokotla~nega preoblikovanja, vro~ega stiskanja in Q&P-postopka za izdelavo funkcionalnih proizvodov z dobrimi mehanskimi lastnostmi in zapleteno obliko. Namen eksperimentalnega dela je bil postaviti proizvodno verigo za izdelavo votlih tankostenskih kosov. Z optimizacijo korak za korakom so bili izdelani komercialno uporabni proizvodi. Mikrostruktura proizvodov je bila sestavljena predvsem iz martenzita in majhnega dele`a bainita. Taka mikrostruktura zagotavlja veliko natezno trdnost. Nivo trdnosti po vsem kosu ni bil manj{i od 1950 MPa v kombinaciji z odli~nim raztezkom okrog 15 %. Klju~ne besede: Q&P-proces, vro~e stiskanje, preoblikovanje z velikim notranjim tlakom

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“…1 were applied to improve toughness of ductile cast iron, high carbon tool steel and spring steel and named ''Up-quenched Austempering'' 32) and ''Quenching and Partitioning''. 33) These technologies aim principally at improving toughness; Si-Mn steel is quenched to a bath at about 250 C after austenitizing, then directly heated to 300-350 C for tempering, and austenite grains are partitioned by bainitic decomposition during the tempering. However, austenite of high Cr steel is stabilized at low temperatures and bainitic decomposition and as a consequence partitioning of austenite hardly occur in most cases.…”

Section: Relation Among Similar Heat Treatmentsmentioning

confidence: 99%

Effect of Martensitizing Temperature on Creep Strength of Modified 9Cr Steel

et al. 2011

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A modified 9Cr-1Mo steel was cooled to a temperature between the M s point and room temperature from the normalizing temperature and then directly heated to the tempering temperature. It was found that the time to rupture at 650 and 700 C of the steel heat-treated by the new heat treatment increased 2-3 times longer than that of the steel conventionally normalized and tempered. The microstructure of the improved steel was tempered martensite and the size of martensite blocks was larger than for the conventional heat treatment. The hardness of the improved steel was fully recovered after tempering. This strengthening is not caused by fresh martensite, but caused by the refining of M 23 C 6 and V(C,N) particles in addition to the increase in the martesite block size, where M denotes metallic elements.

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The "quenching and partitioning" process: background and recent progress

Cited by 294 publications

References 11 publications

Quenching and partitioning heat treatment in ductile cast irons

Quenching and partitioning heat treatment in ductile cast irons

Production of shaped semi-products from AHS steels by internal pressure

Effect of Martensitizing Temperature on Creep Strength of Modified 9Cr Steel

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