Microstructures and yield strength of nitrogen alloyed super duplex steels

Horvath, W.; Tabernig, B.; Werner, Ewald; Uggowitzer, Peter J.

doi:10.1016/s1359-6454(96)00263-7

Cited by 32 publications

(14 citation statements)

References 10 publications

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“…For the material with duplex constituents/phases, the average hardness can be calculated using the classical rule of mixture (ROM) [33,34]:

H_{V} = f_{x} H_{V x} + f_{y} H_{V y}

where

f_{x}

and

f_{y}

are the local x- and y-constituent volume fractions in the tested regions; and

H_{V x}

and

H_{V y}

are the hardness for bulk X and Y crystals. Consequently, the yield stress of the studied steel can be estimated as follows:

σ_{Y} = f_{α} \frac{{H_{V}}^{α}}{3} + f_{γ} \frac{{H_{V}}^{γ}}{3} = 900 M P a

…”

Section: Discussionmentioning

confidence: 99%

Effects of Intercritical Annealing Temperature on Mechanical Properties of Fe-7.9Mn-0.14Si-0.05Al-0.07C Steel

et al. 2014

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A medium Mn steel has been designed to achieve an excellent combination of strength and ductility based on the TRIP (Transformation Induced Plasticity) concept for automotive applications. Following six passes of hot rolling at 850 °C, the Fe-7.9Mn-0.14Si-0.05Al-0.07C (wt.%) steel was warm-rolled at 630 °C for seven passes and subsequently air cooled to room temperature. The sample was subsequently intercritically annealed at various temperatures for 30 min to promote the reverse transformation of martensite into austenite. The obtained results show that the highest volume fraction of austenite is 39% for the sample annealed at 600 °C. This specimen exhibits a yield stress of 910 MPa and a high ultimate tensile stress of 1600 MPa, with an elongation-to-failure of 0.29 at a strain rate of 1 × 10−3/s. The enhanced work-hardening ability of the investigated steel is closely related to martensitic transformation and the interaction of dislocations. Especially, the alternate arrangement of acicular ferrite (soft phase) and ultrafine austenite lamellae (50–200 nm, strong and ductile phase) is the key factor contributing to the excellent combination of strength and ductility. On the other hand, the as-warm-rolled sample also exhibits the excellent combination of strength and ductility, with elongation-to-failure much higher than those annealed at temperatures above 630 °C.

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“…For the material with duplex constituents/phases, the average hardness can be calculated using the classical rule of mixture (ROM) [33,34]:

H_{V} = f_{x} H_{V x} + f_{y} H_{V y}

where

f_{x}

and

f_{y}

are the local x- and y-constituent volume fractions in the tested regions; and

H_{V x}

and

H_{V y}

are the hardness for bulk X and Y crystals. Consequently, the yield stress of the studied steel can be estimated as follows:

σ_{Y} = f_{α} \frac{{H_{V}}^{α}}{3} + f_{γ} \frac{{H_{V}}^{γ}}{3} = 900 M P a

…”

Section: Discussionmentioning

confidence: 99%

Effects of Intercritical Annealing Temperature on Mechanical Properties of Fe-7.9Mn-0.14Si-0.05Al-0.07C Steel

et al. 2014

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“…Contiguity is a measure of phase connectivity, [5,6] which is an important factor for both strength and stiffness. [7] Starting with a virtual specimen, a bundle of rays is passed through the specimen. Along each ray, statistics are collected related to whether a different phase is encountered when the ray leaves one crystal and enters another.…”

Section: Digital Probesmentioning

confidence: 99%

An accelerated methodology for the evaluation of critical properties in polyphase alloys

Dawson

Miller

Han

2005

Metall Mater Trans A

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A system for more rapidly determining the strength and stiffness of polyphase alloys is presented that is based on a digital representation of the material structure. Working in concert with the representation are a number of digital tools and probes that are analogues of testing equipment and instrumentation of traditional laboratory methods. These are combined with nontraditional mechanical testing methods to complete the system. An example of an Fe-Cu system is used to illustrate the methodology.

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“…The choice of the RVE dimensions is based on the convergence studies of the geometrical properties of microstructures similar to the present one, [73]. Periodic boundary conditions are applied to the faces of the RVE, [8,53]. If just generalised plane strain conditions are assumed, i.e.…”

Section: Micromechanical Finite Element Rve Models With Duplex Topolomentioning

confidence: 99%

On material immanent ratchetting of two-phase materials under cyclic purely thermal loading

Silberschmidt¹,

Rammerstorfer

Werner³

et al. 1999

Archive of Applied Mechanics (Ingenieur Archiv)

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The paper analyses speci®c features of the response of two-phase materials with different thermomechanical properties of the phases to purely thermal cycling. It is shown that even without mechanical loading both shakedown and ratchetting regimes are possible. A short review is given of the phenomena and various models of shakedown and ratchetting under cyclic thermomechanical loading. Three structural models for the description of a special two-phase material, namely the duplex stainless steel, under purely thermal loading are discussed: a simple two-bar model, a composite cylinder model and micromechanical ®nite element models with duplex topologies. These models account for different features of the deformation process during thermal cycling and are used as basis for the analysis of thermal ratchetting. Results of numerical simulations are presented for various material conditions and modelling schemes.Conditions for material immanent ratchetting are derived and veri®ed by numerical experiments. It is shown that a temperature-dependence of the yield stresses of the two phases, which exhibits an intersection of the corresponding curves within the temperature interval of the cyclic thermal load, enforces this sort of ratchetting, lacking intersection of the yield stresstemperature curves indicates, on the other hand, a lesser or lacking tendency for material immanent ratchetting. Comparisons with results of laboratory experiment are also presented, and the tendencies derived from the micromechanical models are veri®ed.

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Microstructures and yield strength of nitrogen alloyed super duplex steels

Cited by 32 publications

References 10 publications

Effects of Intercritical Annealing Temperature on Mechanical Properties of Fe-7.9Mn-0.14Si-0.05Al-0.07C Steel

Effects of Intercritical Annealing Temperature on Mechanical Properties of Fe-7.9Mn-0.14Si-0.05Al-0.07C Steel

An accelerated methodology for the evaluation of critical properties in polyphase alloys

On material immanent ratchetting of two-phase materials under cyclic purely thermal loading

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