Martensitic transformation and plastic flow in metastable 2.5 wt.% nickel austenitic stainless steel sheets
TL;DR: In this paper, the tensile properties, martensite forming tendency and formation under biaxial loading of a low Ni (2.5 wt.% Ni) metastable stainless steel were investigated.
About: This article is published in Materials Letters.The article was published on 1999-03-05. It has received 11 citations till now. The article focuses on the topics: Austenitic stainless steel & Martensite.
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TL;DR: In this paper, a combination of cold rolling and annealing was performed on austenitic stainless steels 301, 304 and 304L for a reduction of 75% in strength.
30 citations
01 Jan 2011
TL;DR: In this article, the authors reported that 75% of the users were dissatisfied with the performance of the Thermomechanical Thermodynamics (TTH) and Thermodynamic Thermography (TH) tools.
Abstract: 作为冷滚动并且退火的联合处理的 Thermomechanical 在奥氏体的不锈钢上被执行 301， 304 并且 304L。二冷滚动步直到 75% 的减小的每一个与在 800 点的中间的退火被相结合
27 citations
TL;DR: In this paper, the formability of AISI 202 and 304 stainless steel was compared using Erichsen cupping tests and room temperature uniaxial tensile tests performed at various angles to the rolling direction.
Abstract: The formability of AISI 202 austenitic stainless steel was compared with that of type AISI 304 stainless steel. Type 202 is a low-nickel austenitic stainless steel alloyed with manganese and nitrogen. In this study, the formability of the two grades was examined using Erichsen cupping tests and room temperature uniaxial tensile tests performed at various angles to the rolling direction. AISI 202 appears to work-harden at a slightly higher rate than AISI 304, even though the austenite in type 202 is more stable than that in 304 with respect to the formation of deformation-induced α′ martensite. Although both grades are predicted to be susceptible to earing during deep drawing, AISI 202 displays a higher work-hardening exponent, higher average normal anisotropy, and a higher limiting drawing ratio than AISI 304. Similar cup heights were measured during Erichsen cupping tests, confirming that the two grades have very similar deep drawing properties. The results of this investigation therefore suggest that AISI 202 is a suitable alternative for AISI 304 in applications requiring good deep drawing properties.
26 citations
TL;DR: In this paper, a mechanical press equipped with D2 inserts was used to trim advanced high strength steel (AHSS) sheets with a clearance of 0.14mm (10%), and the mechanisms of AISI D2 steel trim die wear and their effects on plastic deformation and fracture behaviour of the sheared edge of DP980 steel sheet were examined.
16 citations
05 Oct 2012
TL;DR: In this paper, the authors present a list of symbols and abbeviations for the first time, including symbols, symbols, and abbabbevings. But the list is incomplete.
Abstract: ....................................................................................................................................... I PREFACE......................................................................................................................................... III AUTHOR’S CONTRIBUTION ...................................................................................................... IV LIST OF SYMBOLS AND ABBREVIATIONS............................................................................ VI
14 citations
Cites background or result from "Martensitic transformation and plas..."
...This view is further supported by the positive strain rate sensitivity of the yield strength observed at all test conditions and by the strain rate jump tests reported in the literature [84, 97, 102]....
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...This experimental evidence [84, 97, 102] suggests that the instantaneous strain rate sensitivity remains positive despite the large negative strain rate sensitivity of strain hardening rate....
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...10(3) s), but to the author’s knowledge, only a few reports [84, 97, 102] have been published on the instantaneous strain rate sensitivity of austenitic stainless steels undergoing strain-induced γ→α’ phase transformation....
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References
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TL;DR: In this article, the martensitic reaction is treated as a strain transformation with shear and dilatational displacements, respectively parallel and normal to the habit plane, and the resulting effect on the temperature is calculated from the mechanical work done on or by the transforming region as the resolved shear, and normal components of the applied stress are carried through the corresponding transformation strains.
975 citations
TL;DR: In this paper, the von Mises effective strain criterion was used to measure the progress of the γ→α transformation in 304 stainless steel sheet loaded in uniaxial and biaxially tension at both low (10-3 per second and high (103 per second) strain rates.
Abstract: The γ→α transformation in 304 stainless steel can be induced by plastic deformation at room temperature. The kinetics of strain-induced transformations have been modeled recently by Olson and Cohen. We used magnetic techniques to monitor the progress of the γ→α transformation in 304 stainless steel sheet loaded in uniaxial and biaxial tension at both low (10-3 per second) and high (103 per second) strain rates. We found that using the von Mises effective strain criterion gives a reasonable correlation of transformation kinetics under general strain states. The principal effect of increased strain rate was observed at strains greater than 0.25. The temperature increase resulting from adiabatic heating was sufficient to suppress the γ→α transformation substantially at high rates. The consequences of the γ→α transformation on mechanical behavior were noted in uniaxial and biaxial tension. Uniaxial tension tests were conducted at temperatures ranging from 50 to -80°C. We found that both the strain hardening and transformation rates increased with decreasing temperature. However, the martensite transformation saturates at ≈85 pct volume fraction α. This can occur at strains less than 0.3 for conditions where the transformation is rapid. Once saturation occurs, the work hardening rate decreases rapidly and premature local plastic instability results. In biaxial tension, the same tendency toward plastic instability associated with high transformation rates provides a rationale for the low biaxial ductility of 304 stainless steel.
529 citations
TL;DR: In this paper, the effect of hydrogen and stress on the stability of the austenite phase in stainless steels was investigated using X-ray diffraction and magnetic techniques, and the behavior of two “stable” type AISI310 steels and an “unstable, but still ferromagnetic, type of steel was studied during charging and during the outgassing period following charging.
Abstract: The effect of hydrogen and stress (strain) on the stability of the austenite phase in stainless steels was investigated. Hydrogen was introduced by severe cathodic charging and by elevated temperature equilibration with high pressure H2 gas. Using X-ray diffraction and magnetic techniques, the behavior of two “stable” type AISI310 steels and an “unstable” type AISI304 steel was studied during charging and during the outgassing period following charging. Transformation from the fcc γ phase to an expanded fcc phase, γ*, and to the hcp e phase occurred during cathodic charging. Reversion of the γ* and e phases to the original γ structure and formation of the bcc α structure were examined, and the kinetics of these processes was studied. The γ* phase was shown to be ferromagnetic with a subambient Curie temperature. The γ⇆e phase transition was studied after hydrogen charging in high pressure gas, as was the formation of a during outgassing. These results are interpreted as effects of hydrogen and stress (strain) on the stability of the various phases. A proposed psuedo-binary phase diagram for the metal-hydrogen system was proposed to account for the formation of the γ* phase. The relation of these phase changes to hydrogen embrittlement and stress corrosion cracking of stainless steel is discussed.
211 citations
TL;DR: In this article, the deformation behavior of Type 304 stainless steel sheet was evaluated by constant temperature tensile testing in the temperature range of −80 °C to 160 °C, and the contributions of strain rate sensitivity and strain hardening to independent maxima with temperature of uniform and post-uniform strains were discussed.
Abstract: The strain and strain rate dependence of the deformation behavior of Type 304 stainless steel sheet was evaluated by constant temperature tensile testing in the temperature range of −80 °C to 160 °C. The strain rate sensitivity, strain hardening rate, and ductility reflected the compctition of two strengthening mechanisms: strain-induced transformation of austenite to martensite and dislocation substructure formation. At low temperatures, the strain rate sensitivity and strain hardening rate correlated with the strain-induced transformation rate. A maximum in total ductility occurred between 0 °C and 25 °C, and the contributions of strain rate sensitivity and strain hardening to independent maxima with temperature of the uniform and post-uniform strains are discussed.
190 citations