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

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.

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ming-wei Guo ◽  
Zhen-hua Wang ◽  
Ze-an Zhou ◽  
Shu-hua Sun ◽  
Wan-tang Fu

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.


2012 ◽  
Vol 578 ◽  
pp. 202-205
Author(s):  
Guo Qing Lin

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.


2018 ◽  
Vol 37 (9-10) ◽  
pp. 873-888 ◽  
Author(s):  
Nitin Kotkunde ◽  
Hansoge Nitin Krishnamurthy ◽  
Swadesh Kumar Singh ◽  
Gangadhar Jella

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.


2021 ◽  
Vol 1035 ◽  
pp. 328-333
Author(s):  
Li Wei Zhu ◽  
Zhi Shou Zhu ◽  
Xin Nan Wang

The hot deformation behavior of Ti-Al-Nb-Zr-Mo-Cr titanium alloy has been investigated using a Gleeble-1500D thermal simulation test machine in the temperature range of 855°C~1015°C,at constant strain rate from 0.01 s-1 to 10s-1 and with height reduction of 45%. The flow curves characteristic under different deformation parameters show significant difference. According to the stress-strain curves of the alloy and its stress characteristics, the Arrhenius constitutive equation was obtained. The average activation energy is about 541 kJ/mol in the α+β field, and about 243 kJ/mol in the β field, respectively. Based on the dynamic materials model, the processing map is generated, which shows that the peak efficiency domain appears at the temperature of 874°C~900°C and the strain rate of 0.001 s-1~0.06s-1 with a peak efficiency of 0.58 at about 887°C/0.001s-1.


2011 ◽  
Vol 695 ◽  
pp. 361-364 ◽  
Author(s):  
Ying Han ◽  
Guan Jun Qiao ◽  
Dong Na Yan ◽  
De Ning Zou

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.


2013 ◽  
Vol 721 ◽  
pp. 82-85
Author(s):  
Jian Bin Zhang ◽  
Dong Mei Yu ◽  
Shao Rui Niu ◽  
Gen Shun Ji

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.


2016 ◽  
Vol 849 ◽  
pp. 309-316 ◽  
Author(s):  
Li Wei Zhu ◽  
Xin Nan Wang ◽  
Yue Fei ◽  
Jing Li ◽  
Zhi Shou Zhu

The hot deformation behavior of Ti-4.5Al-3V-2Mo-2Fe (SP-700) titanium alloy in the temperature range of 650°C~950°C and constant strain rate of 0.01, 0.1, 1 and 10s-1 has been investigated by hot compressive testing on the Gleeble-1500D thermal simulation test machine. The experimental results indicated that the hot deformation behavior of SP-700 alloy was sensitive to the deformation temperature and strain rate. The peak flow stress decreased with the increase of temperature and the decrease of strain rate. The flow curves characteristic under different deformation parameters show significant different. Analysis of the flow stress dependence on strain rate and temperature gives a stress exponent of n as 4.8235 and a deformation activation energy of Q as 410kJ/mol. Based on the dynamic materials model, the processing map is generated, which shows that the most peak efficiency domain appears at the temperature of 725°C~775°C and the strain rate of 0.001 s-1~0.003s-1 with a peak efficiency of 45% at about 750°C/0.01s-1.


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