Characterization of true stress-true strain curves obtained by hot deformation of different types of steels

1993 ◽  
Vol 29 (7) ◽  
pp. 919-924 ◽  
Author(s):  
G.E.San Martín ◽  
J.E Ruzzante
Keyword(s):  
Hot Deformation ◽  
True Strain ◽  
True Stress ◽  
Different Types

scholarly journals Hot Deformation Process Analysis and Modelling of X153CrMoV12 Steel

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1125 ◽  
Author(s):  
Michal Krbaťa ◽  
Maroš Eckert ◽  
Daniel Križan ◽  
Igor Barényi ◽  
Ivana Mikušová
Keyword(s):  
Hot Deformation ◽  
Process Analysis ◽  
True Strain ◽  
Peak Stress ◽  
High Strength ◽  
True Stress ◽  
Point Of View ◽  
Plastic Behavior ◽  
Hollomon Parameter ◽  
Wide Range

Analysis of the high temperature plastic behavior of high-strength steel X153CrMoV12 was developed in the temperature range of 800–1200 °C and the deformation rate in the range of 0.001–10 s−1 to the maximum value of the true strain 0.9%. Microstructural changes were observed using light optical microscopy (LOM) as well as atomic force microscopy (AFM). The effect of hot deformation temperature on true stress, peak stress and true strain was evaluated from the respective flow curves. Based on these results, steel transformation was discussed from the dynamic recovery and recrystallization point of view. Furthermore, a present model, taking into account the Zener–Hollomon parameter, was developed to predict the true stress and strain over a wide range of temperatures and strain rates. Using constitutive equations, material parameters and activation energy were derived, which can be subsequently applied to other models related to hot deformation behavior of selected tool steels. The experimental data were compassed to the ones obtained by the predictive model with the correlation coefficient R = 0.98267. These results demonstrate an appropriate applicability of the model for experimental materials in hot deformation applications.

scholarly journals Constitutive Equation and Hot Processing Map of a Nitrogen-Bearing Martensitic Stainless Steel

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1502
Author(s):  
Xiao Li ◽  
Lifeng Hou ◽  
Yinghui Wei ◽  
Zhengyan Wei
Keyword(s):  
Stainless Steel ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Processing Map ◽  
Martensitic Stainless Steel ◽  
True Strain ◽  
True Stress ◽  
Hot Working ◽  
Compression Tests

The hot deformation behavior of a nitrogen-bearing martensitic stainless steel was researched by the isothermal compression test in the temperature range of 950–1150 °C and strain rate range of 0.01–10 s−1 with a Gleeble-3800 thermal-mechanical simulating tester. A strain compensated sine-hyperbolic Arrhenius-type constitutive equation was developed to describe the relationship between true stress and deformation parameters such as temperature, strain rate and true strain. The hot deformation activation energy is calculated to be from 407 to 487 KJ mol−1. It is validated by the standard statistical parameters that the established constitutive equation can accurately predict the true stress. The processing maps at different true strains were constructed based on the dynamic material model (DMM) and the true stress data obtained from the hot compression tests. Two unstable regions which should be avoided during hot working were observed from the processing map. In addition, the optimum hot working parameters are located in the domain of 1000–1150 °C/0.1–1 s−1 with the peak power dissipation efficiency of 39.9%, in which complete dynamic recrystallization (DRX) occurs.

Simulated Research on Hot Forming Mechanism of Sour Service Drill Pipe Steel

2011 ◽  
Vol 704-705 ◽  
pp. 266-272
Author(s):  
Mei Juan Hu ◽  
Peng Wang ◽  
Li Hong Han ◽  
Xin Li Han
Keyword(s):  
Constitutive Equation ◽  
Hot Deformation ◽  
Pipe Steel ◽  
True Strain ◽  
Drill Pipe ◽  
Peak Stress ◽  
True Stress ◽  
Experimental Results ◽  
Strain Rates ◽  
Sour Service

The dynamic mechanical behaviors of as-cast sour service drill pipe steel under development during hot deformation were studied in this paper by using Gleeble-3500 thermal mechanical simulator. The compressions were carried out at the temperature of 900°C, 1000°C, 1100°C, 1200°C and strain rates of 10s-1, 1s-1and 0.1s-1. The compress degree was about 70%, and then the maximum true strain for each specimen was 1.2. The experimental results show that the peak stress was related to the compression temperatures and the strain rates. Through respectively analyzing and studying the true stress-true strain curves, the hot deformation constitutive equation and the deformation activation energy were obtained by regression analysis. The evolution of microstructures at various strain rates and temperatures was discussed. Experimental results can provide scientific basis for analyzing the hot deformation processes and controlling quality. Keywords: sour service drill pipe, hot compression, true stress-true strain, constitutive equation, microstructure

Expression of a Generic Full-Range True Stress-True Strain Model for Pipeline Steels Using the Product-Log (Omega) Function

2017 ◽  
Author(s):  
Onyekachi Ndubuaku ◽  
Michael Martens ◽  
J. J. Roger Cheng ◽  
Samer Adeeb
Keyword(s):  
True Strain ◽  
Full Range ◽  
True Stress ◽  
Stress Strain ◽  
Pipeline Steels ◽  
Strain Behavior ◽  
Proposed Model ◽  
Strain Relationship ◽  
Strain Model

Steel pipelines are subjected to a variety of complex, and sometimes difficult to predict, loading schemes during the fabrication, installation and operation phases of their lifecycles. Consequently, the mechanical behavior of steel pipelines is not only influenced by the steel grade but also by the loading history of the pipe segments. Due to the resultant intricacies of the nonlinear load-deformation behavior of pipelines, adequate numerical analysis techniques are usually required for simulation of pipelines under different loading schemes. The validity of such numerical simulations is largely influenced by the accuracy of the true stress-true strain characterization of the pipeline steels. However, existing stress-strain mathematical expressions, developed for the characterization of metallic materials over the full-range of the stress-strain relationship, have been observed to either loose predictive accuracy beyond a limited strain range or, for the more accurate full-range models, are cumbersome due to their requirement of a large number of constituent parameters. This paper presents a relatively accurate and simple true stress-true strain model which is capable of accurately predicting the stress-strain behavior of pipeline steels over the full range of strains. The proposed stress-strain model is characteristically unlike existing stress-strain models as it is essentially defined by a Product-Log function using two proposed parameters, and is capable of capturing a reasonable approximation of the yield plateau in the stress-strain curve. To validate the proposed model, curve-fitting techniques are employed for comparison to experimental data of the stress-strain behavior of different pipeline steel grades (X52 – X100). Excellent agreements are observed between the proposed model and the different pipeline steels over the full-range of the true stress-true strain relationship. Furthermore, the applicability of the proposed model is validated by means of a proposed parametric procedure for predicting the ultimate compressive strength of shell elements.

Characterization of Hot Deformation Behavior of TC18 Titanium Alloy

2015 ◽  
Vol 815 ◽  
pp. 263-267
Author(s):  
Qing Chuan Yang ◽  
Ke Hui Qiu ◽  
Ren Gui Jiang ◽  
De Ming Huang ◽  
Hua Lin He
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Deformation Mechanism ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
True Strain ◽  
Peak Stress ◽  
Compression Tests ◽  
Relationship Model

In this work, hot compression tests on columniform TC18 titanium alloy specimens were performed with a Gleeble® 3500 thermal and mechanical simulator in the temperature range of 820-875 °C and at constant strain rates of 0.01, 0.1 and 1 s−1. Relationship model of true stress versus true strain as well as peak stress versus deformation temperature were established, and microstructural micrographs of TC18 titanium alloy were analyzed. The results showed that the flow stress decreased as the deformation temperature increased or the strain rate decreased. Besides, the deformation resistance at temperature above Tβ (β transus temperature) was obviously lower than that at below Tβ. In addition, flow stresses kept almost constant when it deformed in β region where hot deformation mechanism is DRV, but significant flow softening occurred in α+β region, where deformation mechanism is mainly dominated by DRX. And in α+β region, DRX is prone to occur at a low strain rate, and it is difficult for DRX to occur at high strain rate.

Dynamic Recrystallization of 18Ni(1700MPa) Maraging Steel During Hot Deformation

2012 ◽  
Vol 602-604 ◽  
pp. 441-447 ◽  
Author(s):  
Fei Zhao ◽  
Yong Hai Ren ◽  
Yan Yan
Keyword(s):  
Dynamic Recrystallization ◽  
Maraging Steel ◽  
Hot Deformation ◽  
Critical Stress ◽  
Critical Strain ◽  
True Strain ◽  
Peak Stress ◽  
True Stress ◽  
Strain Rates ◽  
High Deformation

Dynamic recrystallization(DRX) behaviors of 18Ni maraging steel during hot deformation have been investigated by single-pass thermo-mechanical simulative experiment at temperatures of 1173K-1323K and strain rates of 0.001s-1-1s-1. The results show that the true stress-true strain curves type of this alloy is DRX. The DRX in 18Ni maraging steel is easy to occur at low strain rates and high deformation temperatures. Using regression analysis, the activation energy(Q) for DRX of 18Ni maraging steel was calculated to be 413544.96J/mol. The constitutive equation of peak stress for DRX was also obtained. The mathematical models of critical stress and critical strain were finally established.

Electron microscopic characterization of diamond thin films and substrates for diamond heteroepitaxial growth

1989 ◽  
Vol 47 ◽  
pp. 592-593
Author(s):  
J.B. Posthill ◽  
R.P. Burns ◽  
R.A. Rudder ◽  
Y.H. Lee ◽  
R.J. Markunas ◽  
...  
Keyword(s):  
Thin Films ◽  
Wide Band ◽  
Deposition Process ◽  
Heteroepitaxial Growth ◽  
Electron Microscopic ◽  
Wide Band Gap ◽  
Lattice Matching ◽  
Different Types ◽  
Diamond Thin Films

Because of diamond’s wide band gap, high thermal conductivity, high breakdown voltage and high radiation resistance, there is a growing interest in developing diamond-based devices for several new and demanding electronic applications. In developing this technology, there are several new challenges to be overcome. Much of our effort has been directed at developing a diamond deposition process that will permit controlled, epitaxial growth. Also, because of cost and size considerations, it is mandatory that a non-native substrate be developed for heteroepitaxial nucleation and growth of diamond thin films. To this end, we are currently investigating the use of Ni single crystals on which different types of epitaxial metals are grown by molecular beam epitaxy (MBE) for lattice matching to diamond as well as surface chemistry modification. This contribution reports briefly on our microscopic observations that are integral to these endeavors.

Characterization of Different Types of Biomass Wastes Using Thermogravimetric and ICP-MS Analyses

2020 ◽  
Vol 70 (12) ◽  
pp. 4594-4600
Keyword(s):  
Thermogravimetric Analysis ◽  
Food Industry ◽  
Wood Waste ◽  
Biomass Ash ◽  
Minor Elements ◽  
Ms Analysis ◽  
Icp Ms ◽  
Different Types

The purpose of this study was to characterize some types of biomass wastes resulted from different activities such as: agriculture, forestry and food industry using thermogravimetric and ICP-MS analyses. Also, it was optimized an ICP-MS method for the determination of As, Cd and Pb from biomass ash samples. The ICP-MS analysis revealed that the highest concentration of metals (As, Cd, Pb) was recorded in the wood waste ash sample, also the thermogravimetric analysis indicated that the highest amount of ash was obtained for the same sample (26.82%). The biomass wastes mentioned in this study are alternative recyclable materials, reusable as pellets and briquettes. Keywords: ash, biomass, ICP-MS, minor elements, TG

Characterization of different types of broiler bedding including dehydrated grass and their influence on production

2021 ◽  
Vol 92 (1) ◽  
Author(s):  
Bruna B. Przybulinski ◽  
Rodrigo G. Garcia ◽  
Maria Fernanda de C. Burbarelli ◽  
Claudia M. Komiyama ◽  
Deivid Kelly Barbosa ◽  
...  
Keyword(s):  
Different Types

scholarly journals Mutator-Suppressible Alleles of rough sheath1 and liguleless3 in Maize Reveal Multiple Mechanisms for Suppression

Genetics ◽  
2000 ◽  
Vol 154 (1) ◽  
pp. 437-446 ◽  
Author(s):  
Lisa Girard ◽  
Michael Freeling
Keyword(s):  
Untranslated Region ◽  
Mutant Allele ◽  
Negative Regulation ◽  
Wild Type ◽  
Knox Gene ◽  
Transcript Accumulation ◽  
Mu Suppression ◽  
Different Types ◽  
Rna Blot Analysis

Abstract Insertions of Mutator transposons into maize genes can generate suppressible alleles. Mu suppression is when, in the absence of Mu activity, the phenotype of a mutant allele reverts to that of its progenitor. Here we present the characterization of five dominant Mu-suppressible alleles of the knox (knotted1-like homeobox) genes liguleless3 and rough sheath1, which exhibit neomorphic phenotypes in the leaves. RNA blot analysis suggests that Mu suppression affects only the neomorphic aspect of the allele, not the wild-type aspect. Additionally, Mu suppression appears to be exerting its effects at the level of transcription or transcript accumulation. We show that truncated transcripts are produced by three alleles, implying a mechanism for Mu suppression of 5′ untranslated region insertion alleles distinct from that which has been described previously. Additionally, it is found that Mu suppression can be caused by at least three different types of Mutator elements. Evidence presented here suggests that whether an allele is suppressible or not may depend upon the site of insertion. We cite previous work on the knox gene kn1, and discuss our results in the context of interactions between Mu-encoded products and the inherently negative regulation of neomorphic liguleless3 and rough sheath1 transcription.

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