scholarly journals Effect of Nitrogen Content on Hot Deformation Behavior and Grain Growth in Nuclear Grade 316LN Stainless Steel

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ming-wei Guo ◽  
Zhen-hua Wang ◽  
Ze-an Zhou ◽  
Shu-hua Sun ◽  
Wan-tang Fu
Keyword(s):  
Stainless Steel ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Grain Growth ◽  
Strain Rate Sensitivity ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Rate Sensitivity ◽  
Processing Maps ◽  
Hot Deformation Behavior

316LN stainless steel with 0.08%N (08N) and 0.17%N (17N) was compressed at 1073–1473 K and 0.001–10 s−1. The hot deformation behavior was investigated using stress-strain curve analysis, processing maps, and so forth. The microstructure was analyzed through electron backscatter diffraction analysis. Under most conditions, the deformation resistance of 17N was higher than that of 08N. This difference became more pronounced at lower temperatures. The strain rate sensitivity increased with increasing temperature for types of steel. In addition, the higher the N content, the higher the strain rate sensitivity. Hot deformation activation energy increased from 487 kJ/mol to 549 kJ/mol as N concentration was increased from 0.08% to 0.17%. The critical strain for initiation of dynamic recrystallization was lowered with increasing N content. In the processing maps, both power dissipation ratio and unstable region increased with increasing N concentration. In terms of microstructure evolution, N promoted dynamic recrystallization kinetic and decreased dynamic recrystallization grain size. The grain growth rate was lower in 17N than in 08N during heat treatment. Finally, it was found that N favored twin boundary formation.

Hot Deformation Behavior and Processing Maps of Cr-Ni-Mn-N Austenitic Stainless Steel

2011 ◽  
Vol 704-705 ◽  
pp. 210-215
Author(s):  
Er Bao ◽  
Ming Jia Wang ◽  
Zi Xi Wang ◽  
Huan He
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
Power Dissipation ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Processing Maps ◽  
Peak Efficiency ◽  
Hot Deformation Behavior ◽  
Complete Recrystallization ◽  
Gleeble 3500

The hot deformation behavior of a Cr-Ni-Mn-N series stainless steel was studied at temperatures from 850°C to 1175°C with the strain rate ranging from 0.01 s−1 to 10 s−1 using a Gleeble-3500 simulator. The constitutive equation and processing maps were compiled based on a hot compression test to strain of 0.9. The deformation microstructures were observed systematically by optical microscopy. Results show that the efficiency of power dissipation gradually increases with rising temperature and decreasing strain rate. The maps at strains of 0.5 and 0.9 show two distinct domains with one having the peak efficiency of about 28–35% at 1150°C–1175°C and 1–10 s−1 and the other having the peak efficiency of about 33–45% at 1050°C–1150°C and 0.01–0.5 s−1, while complete recrystallization is evident.

Experimental and Numerical Investigations on Hot Deformation Behavior and Processing Maps for ASS 304 and ASS 316

2018 ◽  
Vol 37 (9-10) ◽  
pp. 873-888 ◽  
Author(s):  
Nitin Kotkunde ◽  
Hansoge Nitin Krishnamurthy ◽  
Swadesh Kumar Singh ◽  
Gangadhar Jella
Keyword(s):  
Experimental Data ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Constitutive Models ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Processing Maps ◽  
Hot Deformation Behavior ◽  
Statistical Measures

AbstractA thorough understanding of hot deformation behavior plays a vital role in determining process parameters of hot working processes. Firstly, uniaxial tensile tests have been performed in the temperature ranges of 150 °C–600 °C and strain rate ranges of 0.0001–0.01s−1 for analyzing the deformation behavior of ASS 304 and ASS 316. The phenomenological-based constitutive models namely modified Fields–Backofen (m-FB) and Khan–Huang–Liang (KHL) have been developed. The prediction capability of these models has been verified with experimental data using various statistical measures. Analysis of statistical measures revealed KHL model has good agreement with experimental flow stress data. Through the flow stresses behavior, the processing maps are established and analyzed according to the dynamic materials model (DMM). In the processing map, the variation of the efficiency of the power dissipation is plotted as a function of temperature and strain rate. The processing maps results have been validated with experimental data.

scholarly journals Hot Deformation Behavior Considering Strain Effects and Recrystallization Mechanism of an Al-Zn-Mg-Cu Alloy

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1743 ◽  
Author(s):  
Lei Luo ◽  
Zhiyi Liu ◽  
Song Bai ◽  
Juangang Zhao ◽  
Diping Zeng ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Processing Parameters ◽  
Strain Rate Range ◽  
Hot Compression ◽  
Processing Maps ◽  
Hot Deformation Behavior ◽  
Recrystallization Mechanism ◽  
Cu Alloy

The hot deformation behavior of an Al-Zn-Mg-Cu alloy was investigated by hot compression test at deformation temperatures varying from 320 to 440 °C with strain rates ranging from 0.01 to 10 s−1. The results show that the Mg(Zn, Cu)2 particles as a result of the sufficient static precipitation prior to hot compression have an influence on flow softening. A constitutive model compensated with strain was developed from the experimental results, and it proved to be accurate for predicting the hot deformation behavior. Processing maps at various strains were established. The microstructural evolution demonstrates that the dominant dynamic softening mechanism stems from dynamic recovery (DRV) and partial dynamic recrystallization (DRX). The recrystallization mechanism is continuous dynamic recrystallization (CDRX). The microstructure observations are in good agreement with the results of processing maps. On account of the processing map and microstructural observation, the optimal hot processing parameters at a strain of 0.6 are at deformation temperature range of 390–440 °C and strain rate range of 0.010–0.316 s−1 with a peak efficiency of 0.390.

scholarly journals Hot Deformation Behavior and Processing Maps of Fe-30Mn-0.11C Steel

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1940 ◽  
Author(s):  
Jianmei Kang ◽  
Yuhui Wang ◽  
Zhimeng Wang ◽  
Yiming Zhao ◽  
Yan Peng ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
True Strain ◽  
Peak Stress ◽  
Strain Rates ◽  
Processing Maps ◽  
Compression Tests ◽  
Hot Deformation Behavior ◽  
High Deformation

Hot deformation behavior of Fe-30Mn-0.11C steel was investigated. Hot compression tests were carried out at various temperatures ranging from 800 °C to 1200 °C and at different strain rates of 0.01 s−1 to 10 s−1. The constitutive equation based on peak stress was established. Hot processing maps at different strains and recrystallization diagrams were also established and analyzed. The results show that dynamic recrystallization easily occur at high deformation temperatures and low strain rates. Safe and unstable zones are determined at the true strain of 0.6 and 0.7, and the hot deformation process parameters of partial dynamic recrystallization of the tested steel are also obtained.

Characterization of Hot Deformation Behavior of Zr-4 Alloy in Material Application Area

2012 ◽  
Vol 578 ◽  
pp. 202-205
Author(s):  
Guo Qing Lin
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Flow Behavior ◽  
Strain Rate Range ◽  
Processing Maps ◽  
Peak Efficiency ◽  
Hot Deformation Behavior ◽  
Rate Range ◽  
Temperature Range

The hot deformation behavior of Zr-4 alloy was studied in the temperature range 650-900°C and strain rate range 0.005-50s-1 using processing maps. The processing maps revealed three domains: the first occurs in the temperature range 780-820°C and strain rate range 0.005-0.05s-1, and has a peak efficiency of 45% at 790°C and 0.005s-1; the mechanism is the dynamic recrystallization. The second occurs in the temperature range greater than 900°C and strain rate range 0.05-0.8s-1, and has a peak efficiency of 40% at 900°C and 0.5s-1, which are the domains of dynamic recovery. In addition, the instability zones of flow behavior can also be recognized by the maps in the temperature range 650-780°C and strain rate range 0.01-0.1s-1, which should be strictly avoided in the processing of the material. Zr-4 alloy is the material for pressure tube applications in nuclear reactors and has better strength and a lower rate of hydrogen uptake compared to other materials under similar service conditions.

Artificial Neural Network to Predict the Hot Deformation Behavior of Super 13Cr Martensitic Stainless Steel

2011 ◽  
Vol 695 ◽  
pp. 361-364 ◽  
Author(s):  
Ying Han ◽  
Guan Jun Qiao ◽  
Dong Na Yan ◽  
De Ning Zou
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Stainless Steel ◽  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Martensitic Stainless Steel ◽  
Ann Model ◽  
Hot Deformation Behavior

The hot deformation behavior of super 13Cr martensitic stainless steel was investigated using artificial neural network (ANN). Hot compression tests were carried out at the temperature range of 950°C to 1200°C and strain rate range of 0.1–50s–1at an interval of an order of magnitude. Based on the limited experimental data, the ANN model for the constitutive relationship existed between flow stress and strain, strain rate and deformation temperature was developed by back-propagation (BP) neural network method. A three layer structured network with one hidden layer and ten hidden neurons was trained and the normalization method was employed in training for avoiding over fitting. Modeling results show that the developed ANN model can efficiently predict the flow stress of the steel and reflect the hot deformation behavior in the whole deforming process.

Investigation on Hot Deformation Behavior of 430 Ferritic Stainless Steel

2013 ◽  
Vol 721 ◽  
pp. 82-85
Author(s):  
Jian Bin Zhang ◽  
Dong Mei Yu ◽  
Shao Rui Niu ◽  
Gen Shun Ji
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
Ferritic Stainless Steel ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Flow Behavior ◽  
Peak Stress ◽  
Hot Deformation Behavior ◽  
Hollomon Parameter ◽  
Deformation Equation

The hot deformation behavior and microstructure evolution of 430 ferritic stainless steel (430 FSS) were investigated within the temperature range of 950°C~1150°C at the strain rate of 0.01 s-1, 0.1 s-1, and 1.0 s-1using a thermo-mechanical simulator. The effects of temperature and strain rate on the flow behavior and microstructures of 430 ferritic stainless steel at reduction ratio 50 % were analyzed. Results indicated that the apparent stress exponent and the apparent activation energy of the steel were about 1.08 and 344 kJ/mol, respectively. The hot deformation equation of 430 was considered as. There was a relationship between the softening mechanism and Zener-Hollomon parameter (abbreviated Z). With the Z value increasing from 4.30×1010to 5.00×1014, the hot deformation peak stress correspondingly increased from 10.74 MPa to 76.02MPa.

scholarly journals Characterization of Hot Deformation Behavior and Dislocation Structure Evolution of an Advanced Nickel-Based Superalloy

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 920 ◽  
Author(s):  
Zhihao Yao ◽  
Hongying Wang ◽  
Jianxin Dong ◽  
Jinglin Wang ◽  
He Jiang ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Flow Instability ◽  
Processing Condition ◽  
Constitutive Relationship ◽  
Structure Evolution ◽  
Hot Deformation Behavior

The hot deformation behavior of an advanced nickel-based Haynes282 superalloy was systematically investigated employing isothermal compression tests in the sub-solvus and super-solvus temperature with various strain rates. The influence of deformation temperature and strain rate on the microstructure was studied by transmission electron microscope. The results reveal that the interaction between work hardening and dynamic softening did not reach equilibrium under lower deformation temperature and higher strain rate. The active energy of alloy is around 537.12 kJ/mol and its hot deformation constitutive relationship equation was expressed. According to the processing map and microstructure observations, two unsafe flow instability domains should be avoided. The optimum hot processing condition for homogeneous and fine dynamic recrystallization grains are obtained. TEM micrograph observations indicated that deformation temperature and strain rate affected recrystallization by affecting the evolution of dislocation substructures within the alloy. The nucleation and growth of DRX grains can be promoted by the relatively high deformation temperature and low strain rate. The main mechanism of dynamic recrystallization nucleation preferred to discontinuous dynamic recrystallization and the typical feature of discontinuous dynamic recrystallization showed grain boundary migration nucleation. The findings improve the understanding of hot deformation behavior and dislocation substructures evolution of the superalloy, which benefits the accurate control of microstructures of nickel-based superalloys, and tailors the properties of final components used in the land-based gas turbine.

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