Effect of deformation prior to transformation on the mechanical properties of steel 4340

Kula, Eric B.; Dhosi, Joseph M.

doi:10.1007/bf00812987

Cited by 5 publications

(9 citation statements)

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“…To achieve this, the steel has to be quenched from the austenitisation temperature ( T Aus ) to the deformation temperature ( T D ) fast enough to avoid the formation of pearlite. T D has to be above the martensite‐start temperature ( M S ) and within the so‐called “bainite bay,” in which the metastability of the austenite is time‐dependent . To avoid premature transformation, T D has to be high enough that plastic flow of the austenite is energetically more favorable than the deformation‐induced transformation to martensite .…”

Section: Introductionmentioning

confidence: 99%

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Hardness and Microstructure of a Newly Developed Stainless Steel after Ausforming

Seifert

Botzet

Theisen

2017

steel research int.

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In this work, ausforming is applied to a newly developed stainless steel. This process consists of austenitisation, quenching to a deformation temperature above room temperature, deformation of the metastable austenitic microstructure without the formation of martensite, and subsequent quenching in liquid nitrogen. The investigated steel is explicitly developed to be processed by ausforming and manufactured as a laboratory size test melt. The aim is to achieve a steel having a high hardness as well as a high corrosion resistance. Instead of conventional quenching and tempering, conventional processing is followed by ausforming. A parameter study incorporating the austenitisation temperature and time, deformation temperature, deformation speed, and degree of deformation is performed to achieve maximum hardness. Furthermore, the influence of soft annealing prior to ausforming is also investigated. The hardness of ausformed specimens is measured and correlated to the parameters used for processing. The microstructure of selected specimens is also investigated. Surprisingly, small amounts of martensite are found after ausforming, although a hardness of about 600 HV10 is achieved. In fact, a highly deformed austenitic microstructure is found predominantly.

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Section: Introductionmentioning

confidence: 99%

“…Most studies concentrate on ausforming low‐ and medium‐alloyed steels, simultaneously aiming at high hardness and high ductility . There is only little literature concerning ausforming of corrosion‐resistant ferrites, martensites, or hot‐work tool steels that is also mainly focussing on high hardness and ductility.…”

Section: Introductionmentioning

confidence: 99%

Hardness and Microstructure of a Newly Developed Stainless Steel after Ausforming

Seifert

Botzet

Theisen

2017

steel research int.

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“…[3] During quenching from 900 ЊC to the deformation temperature, the carbide nose of the IT diagram must be avoided, otherwise undesirable carbide formation may result prior to deformation. The benefits of ausforming in enhancing mechanical properties have been reported for plain high-carbon steel, [4] 4340 steel, [5,6] and high-alloy steels containing greater than 3 pct nickel or chromium. The low ausforming temperature is selected to minimize distortion and preserve the refined microstructures produced by deformation.…”

Section: Introductionmentioning

confidence: 99%

“…Fig. Close proximity of the ausforming temperature to the M s temperature was typically avoided in the initial pioneering studies [4][5][6][7][8] for fear of reducing fracture toughness in high-strength ausformed steels. From Lange et.…”

Section: Introductionmentioning

confidence: 99%

Deformation of metastable austenite and resulting properties during the ausform-finishing of 1 pct carburized AlSl 9310 steel gears

Souza

Amateau

1999

Metall Mater Trans A

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The process of ausform-finishing in gears involves the deformation of metastable austenite. A critical step in optimizing the deformation process is to determine the link between material deformation behavior and final material properties, such as hardness and microstructure. To this end, uniaxial compression testing was carried out on 1 pct carburized AISI 9310 steel specimens in the lowtemperature ausforming regime (85 ЊC to 230 ЊC). The work-hardening response of metastable austenite and its relation to the hardness and microstructure was determined from these experiments. High work-hardening rates (work-hardening exponent n ϭ 0.4 to 0.7) were caused by deformationinduced transformation of metastable austenite to either martensite or bainite or both. It is postulated that, at the ausforming temperatures in the neighborhood of 230 ЊC, bainite formed at the highest achievable strains of 50 pct while oriented martensite (loading induced) was detectable at lower strains of 20 pct. The hardness of the resulting ausformed microstructure increased with degree of straining and with reduction in temperature of ausforming. An X-ray determination of the retained austenite content showed that austenite tends to stabilize even after minimal ausforming. A transmission electron microscopy study on ausformed specimens showed the presence of microtwinning and high-dislocation densities. The effect of processing parameters on fatigue response under rolling contact conditions is discussed given current understanding and available fatigue data.

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“…Type and composition of steels investigatedThe AISI 4340 material was selected because of its hardenability and wide industrial use. It also allows comparisons between this work and that of others using different deforma tion modes and strain rates(53).…”

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confidence: 99%

Structure and properties of steels thermo-mechanically processed by impact extrusion

Mayer

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Effect of deformation prior to transformation on the mechanical properties of steel 4340

Cited by 5 publications

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Hardness and Microstructure of a Newly Developed Stainless Steel after Ausforming

Hardness and Microstructure of a Newly Developed Stainless Steel after Ausforming

Deformation of metastable austenite and resulting properties during the ausform-finishing of 1 pct carburized AlSl 9310 steel gears

Structure and properties of steels thermo-mechanically processed by impact extrusion

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